Chemoselectivity Switch between Enantioselective 2,3‐Wittig Rearrangement and Conia‐Ene‐Type Reactions of Propargyloxyoxindoles

Abstract Despite the existence of three competing reactions for propargyloxyoxindoles, we report a chemoselectivity switch between enantioselective propargyl 2,3‐Wittig rearrangement and Conia‐ene‐type reactions, with suppression of the 1,2‐Wittig‐type rearrangement. Using C 1 ‐symmetric imidazolidine‐pyrroloimidazolone pyridine as the ligand and Ni(acac) 2 as the Lewis acid, diverse 3‐hydroxy 3‐substituted oxindoles containing allenyl groups were obtained in up to 98 % yield and 99 % ee via asymmetric propargyl 2,3‐Wittig rearrangement. In the presence of AgOTf‐Duanphos, chiral spiro dihydrofuran oxindoles were given in up to 98 % yield and 91 % ee through a Conia‐ene‐type reaction.