Methods for stereoselective reduction

A method of making a mixture of compounds of formulae II and III:

• or a pharmaceutically acceptable salt thereof, wherein:
• n is 0 or 1;
• R30 is H, alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heterocycloalkyl, aralkyl, heteroaryl, heteroaralkyl, haloalkyl, —OR31, —C(O)R31, —CO2R31, —SO2R31, —C(O)N(R31)(R31), —[C(R)2]q—R31, —[(W)—N(R)C(O)]qR31, —[(W)—C(O)]qR31, —[(W)—C(O)O]qR31, —[(W)—OC(O)]qR3, —[(W)—SO2]qR31, —[(W)N(R31)SO2]qR31, —[(W)—C( O)N(R31)]qR31, —[(W)—O]qR31, —[(W)—N(R)]qR31, —W—(NR31)3+X− or —[(W)—S]qR31;
• W, at each occurrence, independently is an alkylene group;
• q, at each occurrence, independently is 1, 2, 3, 4, 5, or 6;
• X− is a halide;
• R31, at each occurrence, independently is H, alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heterocycloalkyl, aralkyl, heteroaryl, heteroaralkyl or —[C(R)2]p—R32;
• or any two occurrences of R31 taken together with the atom to which they are bound form an optionally substituted 4-8 membered ring that contains 0-3 heteroatoms selected from N, O and S;
• p is 0-6;
• each R32 is independently
• hydroxyl, —N(R)COR, —N(R)C(O)OR, —N(R)SO2(R), —C(O)N(R)2, —OC(O)N(R)(R), —SO2N(R)(R), —N(R)(R), —COOR, —C(O)N(OH)(R), —OS(O)2OR, —S(O)2OR, —OP(O)(OR)(OR), —NP(O)(OR)(OR), or —P(O)(OR)(OR);
• and
• each R is independently H, alkyl, alkenyl, alkynyl, aryl, cycloalkyl or aralkyl;
• the method comprising treating a solution or suspension of compound of formula IV:
• or a pharmaceutically acceptable salt thereof, in a solvent with hydrogen gas in the presence of a catalyst and a substituted pyridine.