Copper-Catalyzed\n[2,3]-Sigmatropic Rearrangement of\nAzide–Ynamides via Selenium Ylides

A copper-catalyzed [2,3]-sigmatropic rearrangement of\nazide–ynamides\nvia selenium ylides is disclosed, which leads to the practical and\ndivergent synthesis of a variety of tricyclic heterocycles bearing\na quaternary carbon stereocenter in generally moderate to excellent\nyields. Significantly, this method represents the first [2,3]-sigmatropic\nrearrangement of the selenium ylide based on alkynes and an unprecedented\n[2,3]-sigmatropic rearrangement via α-imino copper carbenes.