Iridium-Catalyzed X−H Insertions of Sulfoxonium Ylides

The unique reactivity of sulfoxonium ylides as a carbene source is described for a variety of X-H bond insertions, taking advantage of a simple, commercially available iridium catalyst. This method has applications in both intra- and intermolecular reactivity, including a practical ring-expansion strategy for lactams. The safety and stability of sulfoxonium ylides recommend them as preferable surrogates to traditional diazo ketones and esters.