Asymmetric Synthesis of 4,5,6- and 3,4,5,6-Substituted Azepanes by a Highly Diastereoselective and Enantioselective Lithiation−Conjugate Addition Sequence

Asymmetric syntheses of 4,5,6- and 3,4,5,6-substituted azepanes have been achieved by highly diastereoselective and enantioselective (-)-sparteine-mediated asymmetric lithiation-conjugate additions of N-Boc-N-(p-methoxyphenyl)-2,3-substituted allylamines to a beta-aryl alpha,beta-unsaturated ester followed by hydrolysis, cyclization, and reduction. Access to the enantiomeric adduct is provided by an invertive lithiation-stannylation-lithiation sequence.