Enantioselective alkylative double ring-opening of epoxides derived from cyclic allylic ethers: synthesis of enantioenriched unsaturated diolsElectronic supplementary information (ESI) available: the preparation and characterisation of derivatives for ee determinations. See http://www.rsc.org/suppdata/ob/b2/b212404a/
作者:David M. Hodgson、Matthew A. H. Stent、Bogdan Štefane、Francis X. Wilson
DOI:10.1039/b212404a
日期:2003.3.27
enantioselective organolithium-induced alkylative double ring-opening of 3,4-epoxytetrahydrofuran 1 with n-BuLi to give 3-methyleneheptane-1,2-diol 3 in 75% yield and 55% ee in the presence of bisoxazoline 10, and in up to 60% ee in the presence of (-)-sparteine 2. Extending the alkylative double ring-opening reaction to epoxides derived from oxabicyclo[n.2.1]alkenes (n = 2.3) results in the formation
外部手性配体的筛选已导致对映选择性有机锂诱导的3,4-环氧四氢呋喃1与n-BuLi的烷基化双开环反应产生3-亚甲基庚烷-1,2-二醇3,产率为75%,ee为55%。在存在双恶唑啉10的情况下,以及在存在(-)-天冬氨酸2的情况下,在高达60%ee的条件下,将烷基化双开环反应扩展至衍生自oxabicyclo [n.2.1]烯烃(n = 2.3)的环氧化物环烯二醇的形成,当在(-)-天冬氨酸2的存在下进行时,可以提供高达85%ee的产物。