Highly enantioselective hydrogenation of α-Alkyl-β-arylpropenoic acids over cinchonidine-modified palladium catalyst

Abstract

Enantioselective hydrogenation of (E)- α-alkyl-β-arylpropenoic acids was studied over the cinchonidine-modified Pd/C under the conditions optimized for (E)-α,β-diarylpropenoic acids. Enantiomeric excess (ee) of the product was increased by adjusting the α-alkyl group as a properly bulky isopropyl. The ee was as high as 80% when the β-group is phenyl, and reached 86% with p-anisyl group. Stereoselection of those substrates is similar to that of (E)-α,β-diarylpropenoic acids.