Substituted pyrrolidine and related compounds

A compound of formula X:

• wherein
• P is an amino-protecting group;
• each R1 and R2 is independently selected from C1-4 alkyl, C2-4 alkenyl, C2-4 alkynyl, C3-6 cycloalkyl, cyano, halo, —ORa, —SRa, —S(O)Ra, —S(O)2Ra and —NRbRc;
• or two adjacent R1 groups or two adjacent R2 groups are joined to form C3-6 alkylene, —(C2-4 alkylene)-O— or —O—(C1-4 alkylene)-O—;
• each R3 is independently selected from C1-4 alkyl and fluoro;
• each R4 is independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl, C6-10 aryl, C2-9 heteroaryl, C3-6 heterocyclic, —CH2—R6 and —CH2CH2—R7;
• or both R4 groups are joined together with the nitrogen atom to which they are attached to form C3-6 heterocyclic;
• R5 is selected from C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl, and —CH2—R8;
• wherein each alkyl, alkenyl, alkynyl and cycloalkyl group is optionally substituted with —OH or 1 to 3 fluoro substituents;
• each R6 is independently selected from C3-6 cycloalkyl, C6-10 aryl, C2-9 heteroaryl and C3-6 heterocyclic;
• each R7 is independently selected from C3-6 cycloalkyl, C6-10 aryl, C2-9 heteroaryl, C3-6 heterocyclic, —OH, —O(C1-6 alkyl), —O(C3-6 cycloalkyl), —O(C6-10 aryl), —O(C2-9 heteroaryl), —S(C1-6 alkyl), —S(O)(C1-6 alkyl), —S(O)2(C1-6 alkyl), —S(C3-6 cycloalkyl), —S(O)(C3-6 cycloalkyl), —S(O)2(C3-6 cycloalkyl), —S(C6-10 aryl), —S(O)(C6-10 aryl), —S(O)2(C6-10 aryl), —S(C2-9 heteroaryl), —S(O)(C2-9 heteroaryl) and —S(O)2(C2-9 heteroaryl);
• each R8 is independently selected from C3-6 cycloalkyl, C6-10 aryl, C2-9 heteroaryl and C3-6 heterocyclic;
• each Ra is independently selected from hydrogen, C1-4 alkyl, C2-4 alkenyl, C2-4 alkynyl and C3-6 cycloalkyl;
• each Rb and Rc is independently selected from hydrogen, C1-4 alkyl, C2-4 alkenyl, C2-4 alkynyl and C3-6 cycloalkyl;
• or Rb and Rc are joined together with the nitrogen atom to which they are attached to form C3-6 heterocyclic;
• a is an integer from 0 to 3;
• b is an integer from 0 to 3;
• c is an integer from 0 to 4;
• d is 1 or 2;
• and
• e is 8 or 9;
• wherein each alkyl, alkylene, alkenyl, alkynyl and cycloalkyl group in R1, R2, R3, R4, R7, Ra, Rb and Rc is optionally substituted with 1 to 5 fluoro substituents;
• each aryl, cycloalkyl, heteroaryl and heterocyclic group in R1, R2, R4, R5, R6, R7, R8, Ra, Rb and Rc is optionally substituted with 1 to 3 substituents independently selected from C1-4 alkyl, C2-4 alkenyl, C2-4 alkynyl, cyano, halo, —O(C1-4 alkyl), —S(C1-4 alkyl), —S(O)(C1-4 alkyl), —S(O)2(C1-4 alkyl), —NH2, —NH(C1-4 alkyl) and —N(C1-4 alkyl)2, wherein each alkyl, alkenyl and alkynyl group is optionally substituted with 1 to 5 fluoro substituents;
• and each —CH2— group in —(CH2)e— is optionally substituted with 1 or 2 substituents independently selected from C1-2 alkyl, —OH and fluoro;
• or a salt or solvate or stereoisomer thereof.