Stereoselective synthesis of the optical isomers of a new muscarinic receptor antagonist,quinuclidin-3-yl 2-(cyclopent-1-enyl)-2-hydroxy-2-phenylacetate

Abstract

The enantiopure isomers of a new muscarinic receptor antagonist, quinuclidin-3-yl 2- (cyclopent-1-enyl)-2-hydroxy-2-phenylacetate were synthesised by a practical stereoselective synthetic method, using pivaldehyde as steric hindrance agent from the chiral starting material, (S) or (R)-mandelic acid. The isomers were obtained with 72–78 % yields in 98–99 % e.e.