Enantioselective desymmetrization of diphenylphosphinamides via (−)-sparteine-mediated ortho-Lithiation. Synthesis of P-Chiral ligands

Abstract

Asymmetric ortho-lithiation of N-dialkyl-P,P-diphenylphosphinamides using [n-BuLi·(−)-sparteine] is described as an efficient method for the synthesis of P-chiral ortho-functionalized derivatives in high yields and ee’s from 45 to >99%. The method allows access to new enantiomerically pure P-chiral phosphine and diimine ligands.