Intramolecular Interception of the Remote Position of Vinylcarbene Silver Complex Intermediates by C(sp3)−H Bond Insertion

The trapping of the elusive vinylogous position of a vinyl carbene with an aliphatic C(sp³)−H bond has been achieved for the first time during a silver-catalyzed carbene/alkyne metathesis (CAM) process. A Tp^x-containing silver complex first promotes the generation of a donor-acceptor silver carbene which triggers CAM, generating a subsequent donor-donor vinyl silver carbene species, which then undergoes a selective vinylogous C(sp³)−H bond insertion, leading to the synthesis of a new family of benzoazepines. Density functional theory (DFT) calculations unveil the reaction mechanism, which allows proposing that the C−H bond insertion reaction takes place in a stepwise manner, with the hydrogen shift being the rate determining step.