Asymmetric Catalytic Synthesis of Allylic Sulfenamides from Vinyl α‐Diazo Compounds by a Rearrangement Route

The asymmetric rearrangement of allylic sulfilimines is an effective route to synthetic attractive targets such as allylic sulfenamides and others. The current methods are limited to chirality transfer from chiral allylic sulfilimine precursors. Herein, we report a general and fundamentally new rearrangement route accessing optically enriched allylic sulfenamides and their derivatives. The process involves a S‐alkylation and an unusual S‐to‐N rearrangement step. The chiral nickel complex enables the transformation of a broad scope of sulfenamides and vinyl α‐diazo pyrazoleamides under mild conditions. Various allylic sulfenamides have been synthesized with excellent γ‐regioselectivity and enantioselectivity, which can be efficiently converted to sulfinamide and 4‐aminobutenoic acid derivatives. In addition, DFT calculations demonstrate the connection between the spin state and conformation of nickel vinyl carbenoid, as well as an unknown rearrangement process.