Absolute stereochemistry of the peroxy-acid–imine route to optically active oxaziridines

Abstract

The stereochemistry of oxidation of optically active or racemic N-diphenylmethylene-α-methylbenzylamine with chiral or achiral peroxy-acids to oxaziridines of known absolute configuration over a range of reaction conditions has been studied. The diastereoselectivity depends only on temperature, whereas the enantioselectivity depends on the chirality of the peroxy-acid, the temperature, and the solvent. Oxidation of racemic imine with S-peroxy-acids yields, under kinetic control, two optically active negative diastereoisomers with a predominance of (2S,αR)- and (2R,αS)-products over (2S,αS)- and (2R,αR)-isomers. The results are discussed in conjunction with the problem of one- and two-step mechanisms and with the question of absolute configuration at chiral nitrogen in optically active oxaziridines.