Deracemization of α-substituted arylacetic acids

Article abstract of DOI:10.1016/0957-4166(96)00129-2

Reaction of rac-α-substituted arylacetyl chlorides with (R)- and (S)-3-hydroxy-4,4-dimethyl-1-phenyl-2-pyrrolidinone under standard esterification conditions, gave esters (3R,αR)- and (3S,αS)-3, respectively, with a diastereoselectivity which diminishes on increasing the steric effect of the α-substituent. Controlled acidic hydrolysis of esters 3 afforded the corresponding acids 4 with minimal racemization. Boron tribromide demethylation of (R)- and (S)-4d gave without racemization the hydroxyacids (R)- and (S)-4e, known precursors of (R)- and (S)-iodoalphionic acid.