作者:Radha Bam、Alexandros S. Pollatos、Austin J. Moser、Julian G. West
DOI:10.1039/d0sc05925k
日期:——
Herein we report a light-driven B12-based catalytic system that leverages this reactivity to convert alkyl electrophiles to olefins under incredibly mild conditions using only earth abundant elements. Further, this process exhibits a high level of regioselectivity, producing terminal olefins in moderate to excellent yield and exceptional selectivity. Finally, we are able to access a hitherto-unknown
脱卤化氢或消除卤化氢等价物仍然是安装生物学上重要的烯烃官能团的最简单方法之一。然而,这种转化通常需要苛刻的强碱性条件、稀有贵金属或两者兼而有之,限制了其在复杂分子合成中的适用性。Nature 在新型维生素 B 12依赖性光感受器 CarH 中寻求一种补充方法,其中钴-碳键的光解导致在温和的生理相关条件下选择性形成烯烃。在这里,我们报告了一个光驱动的 B 12基于催化系统,利用这种反应性在极其温和的条件下仅使用地球丰富的元素将烷基亲电子试剂转化为烯烃。此外,该工艺表现出高水平的区域选择性,以中等至优异的收率和出色的选择性生产末端烯烃。最后,我们能够使用两种钴催化剂串联使用迄今为止未知的转化,远程消除来生产具有优异区域选择性的亚末端烯烃。我们一起展示了维生素 B 12是开发温和烯烃形成反应的强大平台。
A Mild, Palladium-Catalyzed Method for the Dehydrohalogenation of Alkyl Bromides: Synthetic and Mechanistic Studies
作者:Alex C. Bissember、Anna Levina、Gregory C. Fu
DOI:10.1021/ja306323x
日期:2012.8.29
accomplish palladium-catalyzed dehydrohalogenations of alkyl bromides to form terminal olefins. We have applied this method, which proceeds in excellent yield at room temperature in the presence of a variety of functional groups, to a formal total synthesis of (R)-mevalonolactone. Our mechanistic studies have established that the rate-determining step can vary with the structure of the alkyl bromide and