Synthesis of Silaphenalenes by Ruthenium-Catalyzed Annulation between 1-Naphthylsilanes and Internal Alkynes through C-H Bond Cleavage

Article abstract of DOI:10.1002/chem.201502746

Ruthenium-catalyzed annulation of 1-naphthylsilanes with internal alkynes afforded silaphenalenes through cleavage of the C-H bond at the 8-position of the naphthalene. [RuH₂(CO){P(p-FC₆H₄)₃}₃] efficiently catalyzed the reaction. The use of 1-naphthyldiphenylsilane as a substrate resulted in a better yield of the annulation product compared to the use of silanes with alkyl groups on the silicon atom. Internal alkynes with both aryl and alkyl groups were tolerated in this reaction. Annulation rather than hydrosilylation: A ruthenium catalyst favored annulation products rather than hydrosilylation products in the reaction of 1-naphthylsilanes and alkynes. The annulation proceeded with selective cleavage of the C-H bond at the 8-position of naphthalene. Substrate scope revealed that substituents on the silicon atom played a crucial role and the phenyl group helped to increase the yields.