Base effects on the stereoselectivity of the reaction of (2R,3R)-2,3-Diacetoxy- and (2R,3R)-2,3-Dibenzoyloxy-succinic anhydrides with racemic alcohols

Abstract

A study has been made of the effect on the stereoselectivity of the reaction of racemic alcohols with (2R,3R)-2,3-diacetoxy- and (2R,3R)-2,3-dibenzoyloxy-succinic anhydrides, by using various pyridine derivatives as the basic catalyst.

Considerable enhancement in stereoselectivity is observed with increasing steric bulk around the basic centre, as for example in substituting 2-methylpyridine for pyridine. However, if the pK_a of the base used differs significantly from that of pyridine, a decrease in stereoselectivity results.