A Chiral, Oxidatively Cleavable Auxiliary in Conjugate Additions of Lithium Amides. Preparation of Enantiomerically Pure β-Amino Acid Derivatives

Abstract

Addition of enantiomerically pure 4-methoxyphenethyl-substituted lithium amides to α,β-unsaturated esters leads to β-amino acid derivatives 4-7 with selectivities > 95: 5. The auxiliary can be cleaved by oxidation with cerium(IV) ammonium nitrate (CAN) and subsequent hydrolysis of the resulting mixture of imines.