Access to four-membered cyclic sulfinamides by energy transfer catalysis

Synthetic transformations that advance through excited states proceed by unconventional mechanistic pathways and deliver products not accessible using ground-state chemistry. The breadth of these synthetically valuable transformations is constrained by the range of molecules-and particularly the functional groups-that can deliver productive excited states, with most methods using the same functional groups that were defined more than 100 years ago. In this work, we show that N-silyl sulfinylamines can undergo synthetically useful excited-state reactivity accessed using energy transfer catalysts and visible light. We exploit these intermediates in reactions with alkenes to form four-membered cyclic sulfinamide products. The reactions are efficient and broad in scope, and the products are advanced to sulfonamides as well as four-membered cyclic sulfonimidamides.