Asymmetric Synthesis of 456- and 3456-Substituted Azepanes by a Highly Diastereoselective and Enantioselective Lithiation-Conjugate Addition Sequence

摘要

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 β-aryl α,β-unsaturated esters followed by hydrolysis, cyclization and reduction. Access to the enantiomeric adduct is provided by an invertive lithiation-stannylation-lithiation sequence.