Methods for the synthesis of chiral sulfur heterocycles and their application in the asymmetric Baylis–Hillman reactions
摘要:
Enantiomerically pure (2S,6S)-2,6-diphenyltetrahydro-2H-thiopyran, (2S)-2-phenyltetrahydro thiophene, and (2S)-2-phenyltetrahydro-2H-thiopyran were prepared in 70-72% yields and with 86-99% ee via cyclization of the corresponding dimesylate in an S(N)2 cyclization reaction using sodium sulfide nonahydrate. The results on the application of various chiral sulfides in asymmetric Baylis-Hillman reactions are also described. (C) 2013 Elsevier Ltd. All rights reserved.
Chiral 3-aminopyrrolidines as a rigid diamino scaffold for organocatalysis and organometallic chemistry
作者:Mickael Pouliquen、Jérôme Blanchet、Michaël De Paolis、B. Rema Devi、Jacques Rouden、Marie-Claire Lasne、Jacques Maddaluno
DOI:10.1016/j.tetasy.2010.04.038
日期:2010.6
Over 20 new and easily prepared diamines were screened for the asymmetric Morita-Baylis-Hillman reaction. Chiral non-racemic 3-(N,N-dimethylamino)-1-methylpyrrolidine was found to promote efficiently the reaction of methyl vinyl ketone and substituted benzaldehydes. Enantiomeric excesses up to 73% were reached with electron-deficient benzaldehyde derivatives. After a simple deprotonation, one of these diamines was transformed into a chiral mixed aggregate for the enantioselective synthesis of (R)-1-o-tolylethanol with 76% ee. (C) 2010 Elsevier Ltd. All rights reserved.