Reaction of Thioesters and Selenoesters with Diazo Reagents: Formal Carbene Insertion into C-S and C-Se Bonds.

A reaction of thioesters and selenoesters with doubly stabilized carbenes generated from the corresponding diazo reagents under Rh or Cu catalysis affords products resulting from formal carbene insertion into the C(O)-S and C(O)-Se bonds. The generality of this transformation was demonstrated across a total of 37 examples. A complex reaction mechanism was proposed based on both the isolation of a key intermediate and DFT calculations for the overall reaction pathway. The resulting densely functionalized products, containing up to four different activating groups attached to the same carbon atom, can be readily converted into a variety of valuable compounds through selective and robust defunctionalization reactions.