Asymmetric synthesis of novel C2-symmetric bimorpholines
摘要:
Novel heterocycles-(2S,2'S)-bimorpholine 1 and (3S,3'S)-bimorpholine 2-were synthesised in >98% e.e. starting from tartaric acid ester. (C) 2002 Elsevier Science Ltd. All rights reserved.
The synthesis of 3,3′-bimorpholine and its N-alkyl derivatives is described. These new diamine derivatives were revealed to be efficient organocatalysts for the asymmetric Michael addition of aldehydes to nitroalkenes with excellent enantioselectivity (up to 90% ee). The potential of these organocatalysts was also demonstrated for the highly enantioselective intramolecularaldolreaction affording