Described herein is a novel concept for SN2 reactions at tertiary carbon centers in epoxides without activation of the leaving group. Quantum chemical calculations show why SN2 reactions at tertiary carbon centers are proceeding in these systems. The reaction allows flexible synthesis of 1,3‐diol building blocks for natural product synthesis with excellent control of the relative and absolute configurations
本文描述了在环氧化物中叔碳中心处的S N 2反应而不活化离去基团的新颖概念。量子化学计算表明为什么在这些系统中三级碳中心的S N 2反应正在进行。该反应可以灵活地合成1,3-二醇结构单元,用于天然产物的合成,并具有相对和绝对构型的出色控制。
Asymmetric Epoxidation of Allylic Alcohols Catalyzed by Vanadium–Binaphthylbishydroxamic Acid Complex
acid (BBHA) complex-catalyzed asymmetricepoxidation of allylicalcohols is described. The optically active binaphthyl-based ligands BBHA 2a and 2b were synthesized from (S)-1,1′-binaphthyl-2,2′-dicarboxylic acid and N-substituted-O-trimethylsilyl (TMS)-protected hydroxylamines via a one-pot, three-step procedure. The epoxidations of 2,3,3-trisubstituted allylicalcohols using the vanadium complex of
An Efficient Procedure for the 1,3-Transposition of Allylic Alcohols Based on Lithium Naphthalenide Induced Reductive Elimination of Epoxy Mesylates
作者:Hsing-Jang Liu、Jia-Liang Zhu、Yen-Ku Wu
DOI:10.1055/s-2008-1032092
日期:——
An efficient protocol for the 1,3-transposition of allylic alcohols has been developed. The method is based on the pretransformation of allylic alcohols into the corresponding epoxy mesylates, followed by the reductive elimination of the resulting epoxy mesylates by using lithium naphthalenide (LN) as a reducing agent.
Development and application of versatile bis-hydroxamic acids for catalytic asymmetric oxidation
作者:Allan U. Barlan、Wei Zhang、Hisashi Yamamoto
DOI:10.1016/j.tet.2007.03.071
日期:2007.7
preliminary results of our new designed C(2)-symmetric bis-hydroxamic acid (BHA) ligands and the application of the new ligands for vanadium-catalyzed asymmetric epoxidation of allylic alcohols as well as homoallylic alcohols. From this success we demonstrate the versatile nature of BHA in the molybdenum catalyzed asymmetric oxidation of unfunctionalized olefins and sulfides.
Function-oriented investigations of a peptide-based catalyst that mediates enantioselective allylic alcohol epoxidation.
作者:Nadia C. Abascal、Phillip A. Lichtor、Michael W. Giuliano、Scott J. Miller
DOI:10.1039/c4sc01440e
日期:——
an investigation of a peptide-based catalyst (6) that is effective for the site- (>100:1:1) and enantioselective epoxidation (86% ee) of farnesol. Studies of the substrate scope exhibited by the catalyst are included, along with an exploration of optimized reaction conditions. Mechanistic studies are reported, including relative rate determinations for the catalyst and propionic acid, a historical perspective