Dual-reagent organophosphine catalyzed asymmetric Mannich reactions of isocyanoacetates with N-Boc-aldimines

A combination of an amino-acid derived chiral phosphine catalyst and methyl acrylate has been employed to catalyze the direct Mannich reaction of alpha-aryl isocyanoacetate and N-Boc-aldimines efficiently. The loading of the catalyst could be as low as 0.5 mol% without compromise on the yield and enantioselectivity and the corresponding chiral adducts were obtained in excellent yields (up to 98%) and good enantioselectivities (up to 95%). (C) 2017 Elsevier Ltd. All rights reserved.