Highly Stereoselective Synthesis of Stereochemically Defined Polyhydroxylated Propargylamines by Alkynylation of N‐Benzylimines Derived from (R)‐Glyceraldehyde

Abstract

AbstractThe addition of the lithium derivative of tert‐butyldimethylsilyl propargyl ether to N‐benzylimines derived from (R)‐2,3‐O‐isopropylideneglyceraldehyde has been achieved with acceptable yields and high diastereoselectivities. The syn/anti diastereoselectivity of the addition reaction can be controlled and reversed by the appropriate use of Lewis acids as imine precomplexing agents. Double stereodifferentiation processes using imines derived from (R)‐2,3‐O‐isopropylideneglyceraldehyde and (R)‐ or (S)‐α‐methylbenzylamine as starting materials occur with total stereocontrol to afford syn and anti vic‐propargylamino alcohol derivatives with orthogonally protected hydroxymethyl groups on both sides of the central core.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)