Convenient in situ synthesis of nonracemic N-protected beta-amino aldehydes from beta-amino acids. Applications in Wittig reactions and heterocycle synthesis

N-Z-gamma-amino alcohols derived from nonracemic beta-amino acids are smoot hly oxidised by manganese dioxide in acetonitrile to afford aldehydes which can be trapped in situ in Wittig reactions with carbonyl-substituted phosp horanes. The application of this methodology to the synthesis of the alkalo ids (S)-(+)-N-BOC-coniine, (S)-(-)-coniceine and a pipecoline precursor is described. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.