通过用硫酸亚铁-乙酸亚铜试剂分解氢过氧化物烷基1-8,进行远程未活化C原子的分子内官能化,并获得主要在δ位具有双键的不饱和醇。反应进行,其中包含相应的烷氧基自由基9和δ-碳自由基10作为中间体。乙酸铜单电子氧化δ-碳自由基不涉及相应的碳离子;取而代之的是,形成烷基铜中间体11,并通过消除得到烯烃醇。发现该消除过程的同位素效应为k h / k d = 6.1。
The organocuprates derived from reaction of Grignard reagents with CuBr·Me2S react with 5-lithio-2,3-dihydrofuran and 6-lithio-3,4-dihydro-2H-pyran via a 1,2-metallate rearrangement to generate an alkenylmagnesium cuprate.
Asymmetric 5-endo chloroetherification of homoallylic alcohols toward the synthesis of chiral β-chlorotetrahydrofurans
作者:Xianghua Zeng、Chengxia Miao、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1039/c2cc38436a
日期:——
An asymmetric 5-endo chloroetherification of homoallylic alcohols is successfully developed that employs an easily available quaternary ammonium salt derived from cinchonine as a conventional organocatalyst. This approach provides ready access to beta-chlorotetrahydrofurans in high enantioselectivities.
Substrate-Directed Enantioselective Aziridination of Alkenyl Alcohols Controlled by a Chiral Cation
作者:Alexander Fanourakis、Nicholas J. Hodson、Arthur R. Lit、Robert J. Phipps
DOI:10.1021/jacs.3c00693
日期:——
Alkeneaziridination is a highly versatile transformation for the construction of chiral nitrogen-containing compounds. Inspired by the success of analogous substrate-directed epoxidations, we report an enantioselective aziridination of alkenyl alcohols, which enables asymmetric nitrene transfer to alkenes with varied substitution patterns, including those not covered by the current protocols. We believe