Efficient Access to 5-Acylated Benzoxasilepines Enabled by NHC/Pd Cooperative Catalysis

Abstract

The termination of the endo-selective cyclization of 2-vinylphenol-derived iodomethylsilyl ether has been limited to hydrogen atom abstraction or transition metal-induced β-hydride elimination, affording non-substituted benzoxasilepines. Herein, we report the efficient access to 5-acylated benzoxasilepines by combining the palladium-catalyzed endo-selective cyclization and NHC-catalyzed radical acylation. This method enables the NHC-catalyzed radical cross-coupling step as an effective termination process for the endo-selective cyclization, yielding a variety of 5-acylated benzoxasilepines with good antifungal activity.