Synthesis of halichondrins

A method of preparing a compound of Formula (H3-2-I):

• or a salt thereof, the method comprising cyclizing a compound of Formula (H3-2-II):
• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP4, RP5, and RP6 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (H3-2-II):

• or a salt thereof, comprising coupling a compound of Formula (L-2-6):
• or a salt thereof, with a compound of Formula (R-2-I):
• or a salt thereof, to yield a compound of Formula (H3-2-II), or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• X1 is halogen or a leaving group;
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP4, RP5, and RP6 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (R-2-I):

• or a salt thereof, the method comprising reacting a compound of Formula (R-4-11B):
• or a salt thereof, in the presence of a nucleophile, thereby substituting the group —ORP7 with the group —X1;
• wherein:
• X1 is halogen or a leaving group;
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP5 is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RP7 is optionally substituted sulfonyl, optionally substituted sulfinyl, optionally substituted phosphoryl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RP5 and RP7 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (L-2-6):

• or a salt thereof, the method comprising reacting a compound of Formula (L-5-7B):
• or a salt thereof, in the presence of a thiolating agent;
• wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

The method of preparing a compound of Formula (E-1):

• or a salt thereof, comprising coupling a compound of the formula (E-L):
• or a salt thereof, with a compound of the formula (E-R):
• or a salt thereof, to yield a compound of the formula (E-1):
• or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• X1 is halogen or a leaving group;
• and
• RP4, RP5, and RP6 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (E-R):

• or a salt thereof, the method comprising reacting a compound of Formula (E-R-1):
• or a salt thereof, in the presence of a nucleophile, thereby substituting the group —ORP7 with the group —X1;
• wherein:
• X1 is halogen or a leaving group;
• RP5 is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RP7 is optionally substituted sulfonyl, optionally substituted sulfinyl, optionally substituted phosphoryl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RP5 and RP7 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (E-L):

• or a salt thereof, the method comprising a step of reacting a compound of Formula (E-L-1):
• or a salt thereof, in the presence of a thiolating agent;
• wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A method for preparing a compound of Formula (C):

• or a salt thereof, the method comprising reacting a compound of Formula (A):
• or a salt thereof, with a compound of Formula (B):
• or a salt thereof, in the presence of nickel and zirconium;
• wherein:
• RA is optionally substituted alkyl;
• RB is optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted carbocyclyl, optionally substituted heteroaryl, or optionally substituted heterocyclyl;
• optionally wherein RA and RB are joined together via a linker, wherein the linker is selected from the group consisting of optionally substituted alkylene, optionally substituted heteroalkylene, optionally substituted alkenylene, optionally substituted heteroalkenylene, optionally substituted alkynylene, optionally substituted heteroalkynylene, optionally substituted arylene, optionally substituted heteroarylene, optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted acylene, and combinations thereof;
• X1 is halogen or a leaving group;
• and
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl.

A method of preparing a compound of Formula (H-2-I):

• or a salt thereof, the method comprising a step of cyclizing a compound of Formula (H-2-II):
• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP1, RP2, RP3, RP4, and RP5 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (HH-2-I):

• or a salt thereof, the method comprising a step of cyclizing a compound of Formula (HH-2-II):
• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP1, RP3, RP4, and RP5 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (NH-2-I):

• or a salt thereof, the method comprising a step of cyclizing a compound of Formula (NH-2-II):
• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP3, RP4, and RP5 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• R7 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A method of preparing a compound of Formula (L-2-14):

• or a salt thereof, the method comprising a step of reacting a compound of Formula (L-5-17):
• or a salt thereof, in the presence of a thiolating agent;
• wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP2, RP3, and RP4 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A method of preparing a compound of Formula (L-2-16):

• or a salt thereof, the method comprising a step of reacting a compound of Formula (L-5-26):
• or a salt thereof, in the presence of a thiolating agent;
• wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP3, and RP4 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A method of preparing a compound of Formula (L-2-15):

• or a salt thereof, the method comprising a step of reacting a compound of Formula (L-5-32):
• or a salt thereof, in the presence of a thiolating agent;
• wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R7 and R8 are independently hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl.

A compound of Formula (E-R):

• or a salt thereof, wherein:
• X1 is halogen or a leaving group;
• and
• RP5 is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (E-R-1):

• or a salt thereof, wherein:
• RP5 is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RP7 is optionally substituted sulfonyl, optionally substituted sulfinyl, optionally substituted phosphoryl, optionally substituted acyl, or an oxygen protecting group;
• and
• optionally wherein RP5 and RP7 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (E-R-7):

• or a salt thereof, wherein:
• each instance of RP5 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (E-R-6):

• or a salt thereof, wherein:
• X3 is halogen or a leaving group;
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (E-R-8):

• or a salt thereof, wherein:
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (E-R-11):

• or a salt thereof, wherein:
• each instance of RP5, RP8, and RP9 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• optionally wherein two RP9 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring.

A compound of Formula (E-R-15):

• or a salt thereof, wherein:
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (E-R-16):

• or a salt thereof, wherein:
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of the Formula (E-L):

• or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (E-L-1):

• or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (E-L-2):

• or a salt thereof, wherein:
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (E-L-6):

• or a salt thereof, wherein:
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (H3-N3):

• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, optionally substituted alkyl, or two R6 groups are taken together to form:
• RP4, RP5, and RP6 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (H3-L):

• or a salt thereof, wherein:
• RL is optionally substituted sulfonyl, optionally substituted sulfinyl, optionally substituted phosphoryl, or optionally substituted acyl;
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP4, RP5, and RP6 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (H3-2-I):

• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• each instance of RP6 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (H3-2-II):

• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP4, RP5, and RP6 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (R-2-I):

• or a salt thereof, wherein:
• X1 is halogen or a leaving group;
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP5 is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (L-2-6):

• or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• RP4 and RP6 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (R-4-11B):

• or a salt thereof, wherein:
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP5 and RP7 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RP7 is optionally substituted sulfonyl, optionally substituted sulfinyl, optionally substituted phosphoryl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RP5 and RP7 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (R-4-11A):

• or a salt thereof, wherein:
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• each instance of RP5 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (R-4-10):

• or a salt thereof, wherein:
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (R-4-8):

• or a salt thereof, wherein:
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• and
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring.

A compound of Formula (R-4-9):

• or a salt thereof, wherein:
• X3 and X2 are each independently halogen or a leaving group;
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (R-4-10B):

• or a salt thereof, wherein:
• X3 is halogen or a leaving group;
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, optionally substituted alkyl, or two R6 groups are taken together to form:
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

Provided herein are compounds of Formula (R-4-7):

• or a salt thereof, wherein:
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (R-4-5B):

• or a salt thereof, wherein:
• R3 is hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP5 and RP8 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (R-4-7A):

• or a salt thereof;
• wherein:
• R3 and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of RP5, RP8, and RP9 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and optionally wherein two RP9 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (R-4-5A):

• or a salt thereof, wherein:
• R3 is hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP5 and RP8 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (R-4-4):

• or salts thereof, wherein:
• R3 is hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP5, RP8, and RP10 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (R-4-2):

• or salt thereof, wherein:
• R3 is hydrogen, halogen, or optionally substituted alkyl;
• and
• each instance of RP5 and RP10 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring.

A compound of Formula (R-4-1):

• or salts thereof, wherein:
• R3 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP5 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP5 groups are joined together with the intervening atoms to form an optionally substituted heterocyclyl ring.

A compound of Formula (L-5-7B):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-7A):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-6A):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (L-5-4):

• or a salt thereof, wherein:
• R1 is independently hydrogen, halogen, or optionally substituted alkyl;
• and
• each RP6 is independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (H-2-II):

• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP1, RP2, RP3, RP4, and RP5 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (L-2-14):

• or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are each independently hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP2, RP3, and RP4 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (HH-2-II):

• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP1, RP3, RP4, and RP5 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (L-2-16):

• or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP3 and RP4 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (NH-2-II):

• or a salt thereof, wherein:
• R1, R2, R3, and R5 are each independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of R4 is independently hydrogen, halogen, or optionally substituted alkyl, or two R4 groups are taken together to form:
• each instance of R6 is independently hydrogen, halogen, or optionally substituted alkyl, or two R6 groups are taken together to form:
• RP3, RP4, and RP5 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• R7 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group;
• RX is hydrogen or —ORXa, wherein RXa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• RY is hydrogen or —ORYa, wherein RYa is hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein RXa and RYa are joined together with their intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (L-2-15):

• or a salt thereof, wherein:
• RS is optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl;
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP3 and RP4 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• R7 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-17):

• or a salt thereof, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP2, RP3, and RP4 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-16B):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP2, RP3, and RP4 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-16A):

• or a salt thereof, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP2, RP3, RP4, and RP10 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-15):

• or a salt thereof, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP2, RP3, RP4, and RP10 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-14):

• or a salt thereof, in the presence of an acid, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP2, RP4, and RP10 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

Provided herein are compounds of Formula (L-5-12):

• and salts thereof, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP2, and RP10 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-11):

• or a salt thereof, wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP2, and RP10 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-26):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP3, and RP4 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, or optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-25C):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP3, and RP4 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-25A):

• or a salt thereof, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP3, and RP4 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-24):

• or a salt thereof, wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1 and RP3 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-23B):

• or a salt thereof, wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP3, and RP10 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-23C):

• or a salt thereof;
• wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP3, and RP10 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-23A):

• or a salt thereof;
• wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP3, and RP10 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-22):

• or a salt thereof;
• wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP3, and RP10 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-22A):

• or a salt thereof;
• wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP3, and RP10 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-21B):

• or a salt thereof;
• wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP6, and RP10 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-21A):

• or a salt thereof;
• wherein:
• R1 is hydrogen, halogen, or optionally substituted alkyl;
• and
• RP6 and RP10 are each independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-32):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R7 and R8 are independently hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-31):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP4, and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-32A):

• or a salt thereof;
• wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• RP1, RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl;
• and
• R8 is hydrogen, optionally substituted alkyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted heteroaryl, optionally substituted acyl, or an oxygen protecting group.

A compound of Formula (L-5-28):

• or a salt thereof, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• RP1, RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group;
• optionally wherein two RP6 are joined with the intervening atoms to form optionally substituted heterocyclyl.

A compound of Formula (L-5-27):

• or a salt thereof, wherein:
• R1 and R2 are independently hydrogen, halogen, or optionally substituted alkyl;
• and
• each instance of RP4 and RP6 are independently hydrogen, optionally substituted alkyl, optionally substituted acyl, or an oxygen protecting group.