Chiral auxiliaries and uses thereof

An enantiomerically enriched compound of the general formula (I):

• or a salt thereof, wherein:
• R1 and R2, where present, may be the same or different and are selected from the group consisting of H, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted arylalkyl, optionally substituted heterocyclylalkyl, optionally substituted heteroarylalkyl, optionally substituted alkenyl, and optionally substituted alkynyl;
• or
• R1 and R2 taken together form a spirocyclic group;
• R3 and R4, where present, may be the same or different and are selected from the group consisting of H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted heteroarylalkyl, optionally substituted benzyl, optionally substituted silyl, optionally substituted acyl, optionally substituted alkoxy and NR5R6;
• wherein at least one of R1, R2, R3 and R4 is not H;
• R5 and R6 may be the same or different and are selected from the group consisting of H, optionally substituted aryl, optionally substituted alkyl and SO2R7;
• R7 is H, alkyl or aryl;
• X is NHR8, OR8 or SR8;
• and
• R8 is H, optionally substituted acyl, optionally substituted alkenylacyl, optionally substituted alkyl or a protecting group.

An enantiomerically enriched compound of the general formula (I):

• or a salt thereof, wherein:
• R1 and R2 may be the same or different and are selected from the group consisting of H, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted arylalkyl, optionally substituted heterocyclylalkyl, optionally substituted heteroarylalkyl, optionally substituted alkenyl, and optionally substituted alkynyl;
• or
• R3 and R4 may be the same or different and are selected from the group consisting of H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted heteroarylalkyl, optionally substituted benzyl, optionally substituted silyl, optionally substituted acyl, optionally substituted alkoxy and NR5R6;
• wherein at least one of R1, R2, R3 and R4 is not H;
• R5 and R6 may be the same or different and are selected from the group consisting of H, optionally substituted aryl, optionally substituted alkyl and SO2R7;
• R7 is H, alkyl or aryl;
• X is NHR8, OR8 or SR8;
• and
• R8 is H, optionally substituted acyl, optionally substituted alkenylacyl, optionally substituted alkyl or a protecting group.

An enantiomerically enriched compound of formula (I′):

• or a salt thereof, wherein:
• R1 and R2 may be the same or different and are selected from the group consisting of H, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted arylalkyl, optionally substituted heterocyclylalkyl, optionally substituted heteroarylalkyl, optionally substituted alkenyl, and optionally substituted alkynyl;
• R3 and R4 may be the same or different and are selected from the group consisting of H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted heteroarylalkyl, optionally substituted benzyl, optionally substituted silyl, optionally substituted acyl, optionally substituted alkoxy and NR5R6;
• wherein at least one of R1, R2, R3 and R4 is not H;
• R5 and R6 may be the same or different and are selected from the group consisting of H, optionally substituted aryl, optionally substituted alkyl and SO2R7;
• R7 is H, alkyl or aryl;
• X is NHR8, OR8 or SR8;
• and
• R8 is H, optionally substituted acyl, optionally substituted alkenylacyl, optionally substituted alkyl or a protecting group.

An enantiomerically enriched compound of formula (I″):

• or a salt thereof, wherein:
• R1 and R2 may be the same or different and are selected from the group consisting of H, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted arylalkyl, optionally substituted heterocyclylalkyl, optionally substituted heteroarylalkyl, optionally substituted alkenyl, and optionally substituted alkynyl;
• X is OR8;
• R8 is H, optionally substituted acyl, optionally substituted alkenylacyl, optionally substituted alkyl or a protecting group.