Zidan Montserrat, McCallum Terry, Swann Rowan, Barriault Louis
Centre for Catalysis, Research and Innovation, Department of Chemistry and Biomolecular Sciences University of Ottawa Ottawa, Ontario K1N 6N5, Canada.
Org Lett. 2020 Nov 6;22(21):8401-8406. doi: 10.1021/acs.orglett.0c03030. Epub 2020 Oct 11.
Organic transformations mediated by photoredox catalysis have been at the forefront of reaction discovery. Recently, it has been demonstrated that binuclear Au(I) bisphosphine complexes, such as [Au(μ-dppm)]X, are capable of mediating electron transfer to nonactivated bromoalkanes for the generation of a variety of alkyl radicals. The transfer reactions of bromine, derived from nonactivated bromoalkanes, are largely unknown. Therefore, we propose that unique metal-based mechanistic pathways are at play, as this binuclear gold catalyst has been known to produce Au(III) Lewis acid intermediates. The scope and proposed mechanistic overview for the formal bromine atom transfer reaction of nonactivated bromoalkanes mediated by photoredox Au(I) catalysis is presented. The methodology presented afforded good yields and a broad scope which include examples using bromoalkanes and iodoarenes.
由光氧化还原催化介导的有机转化一直处于反应发现的前沿。最近，已证明双核Au(I)双膦配合物，如[Au(μ-dppm)]X，能够介导电子转移至未活化的溴代烷烃以生成各种烷基自由基。源自未活化溴代烷烃的溴转移反应在很大程度上尚不清楚。因此，我们提出独特的基于金属的机理途径在起作用，因为已知这种双核金催化剂会产生Au(III)路易斯酸中间体。本文介绍了光氧化还原Au(I)催化介导的未活化溴代烷烃正式溴原子转移反应的范围和提出的机理概述。所展示的方法提供了良好的产率和广泛的范围，包括使用溴代烷烃和碘代芳烃的示例。
