Facile synthesis of 1-silaacenaphthenes by transition metal-catalyzed intramolecular C(sp³)–H silylation

We report a general strategy for synthesizing novel fused aromatic 1-silaacenaphthenes by iridium or rhodium-catalyzed intramolecular C(sp³)-H silylation. Both methods showed similar activity and broad substrate scope, producing a variety of 1-silaacenaphthenes with high functional group tolerance. We found that C-H cleavage was not the rate-determining step and that the reaction was first-order with respect to the initial concentrations of substrate, catalyst and ligand. We also characterized the catalyst resting states using ³¹P NMR and HRMS. Moreover, we used the 1-silaacenaphthenes as synthons for versatile transformations, yielding highly functional molecules.