Catalyst-Free Synthesis of 2,3-Dihydrobenzofurans via a Formal [4+1] Annulation of Propargylamines with Sulfur Ylides
作者:Xinwei He、Mengqing Xie、Qiang Tang、Youpeng Zuo、Ruxue Li、Yongjia Shang
DOI:10.1021/acs.joc.9b01557
日期:2019.9.20
A simple, general route to the 2,3-dihydrobenzofurans substituted at C3 by an aryethynyl or aryl group, starting from propargylamine and its derivatives with benzoyl sulfonium salts, has been developed. This reaction involved an in situ generated o-quinone methide (o-QM) intermediate followed by [4+1] annulation with sulfur ylides. Notably, this protocol's features include moderate to excellent yields
从炔丙基胺及其衍生物与苯甲酰基sulf盐开始,已经开发了一种简单的通用路线,该路线是在C3处被炔基或芳基取代的2,3-二氢苯并呋喃。该反应涉及原位生成的邻醌甲基化物(o-QM)中间体,然后用硫酰化物进行[4 + 1]环化。值得注意的是,该方案的功能包括中等至优异的收率和非对映选择性(通常> 20:1 dr),易于操作,以及可通过CC和CO键形成带有乙炔基或芳基的通用2,3-二氢苯并呋喃。一锅没有任何催化剂的混合水溶液。