Tuning of diastereoselectivity was realized in the Mannichreaction of glycine derivatives with aromatic and aliphatic N-Ts imines using CuClO4-FcPHOX ligand 4b and 4f having an MeO group at the 4-position and F atom at the 3,5-position of the phenyl ring on the P-atom respectively as catalyst, providing either anti- or syn-alpha,beta-diamino acid derivatives in high yields and in high diastereo- and
Synthesis of α,β-diamino acid derivatives via asymmetric Mannich reactions of glycine imino esters catalyzed by a chiral phosphoramidite·silver complex
作者:Alberto Cayuelas、Loane Serrano、Carmen Nájera、José M. Sansano
DOI:10.1016/j.tetasy.2014.11.009
日期:2014.12
AgOTf phosphoramidite complexes efficiently catalyze the enantioselective Mannich-type reaction between benzophenone-imine glycine methyl ester and N-tosyl aldimines in the absence of a base. The corresponding syn-adducts, which are the direct precursors of alpha,beta-diamino acids, are obtained with moderate to good syn-diastereoselectivities (up to 9:1) and high enantioselectivities (up to 99% ee). (C) 2014 Elsevier Ltd. All rights reserved.