Intermolecular and Intramolecular, Platinum‐Catalyzed, Acceptorless Dehydrogenative Coupling of Hydrosilanes with Aryl and Aliphatic Methyl C—H Bonds.

Intermolecular acceptorless dehydrogenative coupling of silanes with arene C−H bonds and intramolecular coupling of silanes with aryl and alkyl C−H bonds occur in good yield in the presence of 5 mol % of Tp<sup>Me</sup><sub><sup>2</sup></sub>PtMe<sub>2</sub>H (Tp<sup>Me</sup><sub><sup>2</sup></sub> = hydridotris(3,5-dimethylpyrazolyl)borate) and related platinum(IV) complexes. The intermolecular reactions of arenes occurred with both trialkyl and dialkylaryl silanes. Intramolecular reactions of dialkylsilylalkylarenes occurred at aryl C−H bonds, and reactions of tributylsilane or dibutylphenylsilane occurred intramolecularly at the aliphatic, primary C−H bond. The reactions of arenes occurred preferentially at the least sterically hindered C−H bonds and preferentially with more electron-poor arenes. Crossover experiments and the lack of reactivity of the arylsilanes with H<sub>2</sub> imply that the dehydrogenative silylation of arenes can be irreversible, even in a closed reaction vessel.