铑(I)催化剂促进邻炔基苯酚和苯胺转化为相应的苯并[ b ]呋喃和吲哚。假定该反应通过过渡的3-铑杂环中间体进行,该中间体可以用合适的亲电试剂捕获以得到多取代的杂环。在单取代的吸电子亲电体的情况下,与Heck-Mizoroki反应相比,可以获得优异的收率和选择性。在2-炔基吡啶亲电试剂的情况下,形成新的2-(苯并呋喃-3-基)乙烯基吡啶。
Au–Ag Bimetallic Catalysis: 3‐Alkynyl Benzofurans from Phenols via Tandem C−H Alkynylation/Oxy‐Alkynylation
作者:Long Hu、Martin C. Dietl、Chunyu Han、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/anie.202016595
日期:2021.5.3
The development of new methodologies enabling a facileaccess to valuable heterocyclic frameworks still is an important subject of research. In this context, we describe a dual catalytic cycle merging C−H alkynylation of phenols and oxy‐alkynylation of the newly introduced triple bond by using a unique redox property and the carbophilic π acidity of gold. Mechanistic studies support the participation
A new method for the arylative cyclization of o-alkynylphenols with aryldiazonium salts via dual photoredox/gold catalysis is described. The reaction proceeds smoothly at roomtemperature in the absence of base and/or additives and offers an efficient approach to benzofuran derivatives. The scope of the transformation is wide, and the limitations are discussed. The reaction is proposed to proceed through