The reaction of nitrones with (R)-(+)-methyl p-tolyl sulfoxide anion; asymmetric synthesis of optically active secondary amines

Abstract

Optically active α-substituted N-hydroxylamines have been prepared by the addition of (R)-(+)-and (S)-(−)-methyl p-tolyl sulfoxide anions to nitrones highly efficiently. This method is applicable to the synthesis of optically active N-hydroxy tetrahydroisoquinoline derivatives 6a–6e, which are important precursors of various isoquinoline alkaloids such as (R)-(+)-salsolidine. (8). Furthermore, the reaction of nitrones bearing chiral sulfinyl group with organometallic reagents provides an efficient method for induction of asymmetric quaternary carbon α to nitrogen of secondary amines.