Co(II)-Catalyzed Intramolecular Carbocyclization of ortho-Alkynylaryl Vinylsilanes to Sila-exocyclic 1,3-Dienes.

Exocyclic 1,3-dienes are often difficult to synthesize owing to their inherent thermodynamic instability. In this study, a Co(II)-catalyzed intramolecular carbocyclization of sila-enynes has been developed to afford benzosilole-fused exocyclic 1,3-dienes through a cascade oxidative cyclization, β-H elimination, and reductive elimination process. The resulting sila-exocyclic 1,3-dienes can serve as versatile platform molecules for further assembling high-value benzosilole derivatives.