Desymmetrization of prochiral anhydrides with Evans' oxazolidinones: an efficient route to homochiral glutaric and adipic acid derivatives

The prochiral recognition between enantiotopic carbonyl groups in the react ion of 3-substituted glutaric and 3,4-disubstituted adipic anhydrides with anions of Evans' oxazolidinones has been investigated. Each of the a-symmet ric anhydrides provided a diastereoisomeric mixture of half-acids which wer e separated either by fractional crystallization or by column chromatograph y of their esters. The diastereoselectivity of the desymmetrization reactio n is dependent on the substituents present in the anhydrides.