Preparation and properties of chiral 4-pyrrolidinopyridine (PPY) analogues with dual functional side chains

Chiral 4-pyrrolidinopyridine analogues 8–13 with two distinct functional side chains at C(2) and C(4) of the pyrrolidine ring were prepared from 4-hydroxy-l-proline. We examined desymmetrization of meso-1,3-cyclohexanediol through enantioselective acylation using these catalysts and found that introduction of a C(4)-side chain was effective for improving both the chemo- and enantioselectivity of acylation.