Silver Vinylcarbenes: From Hypothetical Intermediates to Characterized Reactive Species

Vinylcarbenes generated through carbene–alkyne metathesis are highly versatile intermediates in modern synthetic chemistry, yet they have largely remained mechanistic hypotheses supported by product analysis and computation. Motivated by years of studying transition metal-catalyzed CAM reactions, we sought to answer a fundamental question: can a transition metal vinylcarbene be directly observed and characterized? In this article, we describe how this challenge led to the experimental identification of a silver vinylcarbene and an unexpected mechanistic picture of its subsequent reactivity. We discuss the significance of this breakthrough within the broader evolution of carbene chemistry and highlight how combining spectroscopy, computation, and mechanistic studies can transform elusive intermediates into platforms for the rational development of new catalytic transformations.