A new synthesis of enantiomerically pure syn-(S)-beta-hydroxy-alpha-amino acids via asymmetric aldol reactions of aldehydes with a homochiral Ni(II)-glycine/(S)-BPB Schiff base complex

摘要

syn-(S)-beta -Hydroxy-alpha -amino acids were synthesised stereoselectivity via elaboration of the asymmetric aldol reactions of aldehydes with a chiral Ni(II)-(S)-BPB/glycine Schiff base comp]es in the presence of equimolar NaH in THF. The stereoselectivity of the reaction was studied as a function of rime. the reaction conditions. the nature of the carbonyl compounds and the base used. The synthetic potential of this asymmetric method was demonstrated in the preparation of syn-(S)-beta -hydroxyleucine on a multi-gram scale. (C) 2001 Elsevier Science Ltd. All rights reserved. [References: 24]