Chemoselective, Isomerization-Free Synthesis of N-Acylketimines from N?H Imines

Abstract

N-Acylketimines were synthesized through a ruthenium-catalyzed generation of N?H ketimines from secondary azides and subsequent acylation with mixed anhydrides under mild conditions. The synthetic scope was broad to give N-acylimines having various functional groups, including those with aliphatic groups that are prone to tautomerization to the corresponding enamides. In addition, various acyl moieties were accommodated. The synthetic utility of this chemoselective imine generation was illustrated by a highly diastereoselective nucleophilic addition of a Grignard reagent to a cyclic N-acylimine. (Figure presented.). ? 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim