Construction of Quaternary Carbon Center via NHC Catalysis Initiated by an Intermolecular Heck-Type Alkyl Radical Addition
作者:Lanjun Su、Huan Sun、Jikai Liu、Chengming Wang
DOI:10.1021/acs.orglett.1c01400
日期:2021.6.18
A quaternary carbon center containing an oxindole motif is constructed via NHC-catalyzed transition-metal and aldehyde-free intermolecular Heck-type alkyl radical addition initiated annulation. This redox-neutral protocol also features a simple procedure, broad substrate scope, good functional group tolerance and could be smoothly amplified to a gram scale. The mechanism study shows that the reaction
含有羟吲哚基序的季碳中心是通过 NHC 催化的过渡金属和无醛分子间 Heck 型烷基自由基加成引发的环化构建的。这种氧化还原中性方案还具有程序简单、底物范围广、官能团耐受性好并且可以顺利放大到克级的特点。机理研究表明,该反应可能经历了两次 SET 过程,其中涉及 NHC 自由基阳离子中间体。