Highly enantioselective catalysis of the mukaiyama aldol reaction by BINOL-ti perfluorophenoxide and enoxysilacyclobutane
摘要:
An extremely high level of enantioselectivity is established in the Mukaiyama aldol reaction using perfluorophenol as an effective achiral ligand for binaphthol (BINOL)-derived titanium (IV) catalyst. Enoxysilacyclobutane is more effective as the silyl nucleophile than the usual trimethylsilyl enol ether in the enantioselective catalysis of the Mukaiyama aldol reaction.
Asymmetric carbonyl addition reactions to benzyloxyaldehydes by binaphthol-titanium catalyst: Anti- vs. Syn-diastereofacial preference in anomalous nonchelation complexation
作者:Koichi Mikami、Satoru Matsukawa、Eiji Sawa、Akinori Harada、Nobuaki Koga
DOI:10.1016/s0040-4039(97)00231-1
日期:1997.3
An anomalous nonchelation diastereofacial selectivity is observed in the titanium-catalyzed carbonyl addition reaction to benzyl-protected alkoxyaldehydes. There is a dichotomy in the sense of syn- vs. anti-diastereofacial preference, dictated by the bulkiness of the migratory group: The sterically demanding silyl group gives syn-diastereofacial preference and the less sterically demanding proton lends to anti-diastereofacial preference. (C) 1997 Elsevier Science Ltd.