Chirality transfer in Brook rearrangement-mediated S E 2′ solvolytic protonation and its use in estimation of the propensity for racemization of the α-lithiocarbanions of the substituents
作者: Michiko SasakiMisato FujiwaraYuri KotomoriMasatoshi KawahataKentaro YamaguchiKei Takeda
作者单位: 1Graduate School of Medical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-Ku, Hiroshima 734-8553, Japan
2Tokushima Bunri University, 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan
刊名: Tetrahedron, 2013, Vol.69 (29), pp.5823-5828
来源数据库: Elsevier Journal
DOI: 10.1016/j.tet.2013.05.043
关键词: CarbanionChirality transferRearrangementElectrophilic substitution
英文摘要: Abstract(#br)Chirality transfer from an α-silylalcohol to α-carbmoyloxy- and α-siloxyallyl-carbanions was investigated using a Brook rearrangement-mediated S E 2′ protonation in γ-carbamoyloxy- and γ-siloxy-α-silylallyl alcohols. We proposed a hypothesis that the reaction proceeds along one of two pathways that involves (1) a concerted protonation of a silicate intermediate and (2) a concerted lithiation of the intermediate followed by protonation with retention or by protonation after racemization. Comparison of the extent of the chirality transfer provides a new method for semi-quantitative evaluation of the propensity for racemization of lithiocarbanions next to a conjugative electron-withdrawing group.
全文获取路径: Elsevier  (合作)
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影响因子:2.803 (2012)

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