Au-Catalyzed Oxidative Arylation: Chelation-Induced Turnover of ortho-Substituted Arylsilanes

ortho-Substituted aryl silanes have previously been found to undergo much slower Au-catalyzed intermolecular arylation than their m,p-substituted isomers, with many examples failing to undergo turnover at all. A method to indirectly quantify the rates of C-Si auration of o-substituted aryl silanes, under conditions of turnover, has been developed. All examples are found to undergo very efficient C-Si auration, indicative that it is the subsequent C-H auration that is inhibited by the ortho substituent. A simple Ar-Au conformational model suggests that C-H auration can be accelerated by chelation. A series of ortho-functionalized aryl silanes are shown to undergo efficient arylation.