Catalytic Asymmetric Diels–Alder Reaction/[3,3] Sigmatropic Rearrangement Cascade of 1‐Thiocyanatobutadienes

A highly efficient asymmetric Diels–Alder/3,3] sigmatropic rearrangement reaction of methyleneindolinones with 1‐thiocyanatobutadienes has been realized by using a chiral N,N′‐dioxide/nickel(II) complex as the catalyst. A range of cyclohexenyl isothiocyanates were synthesized in high yields with excellent diastereo‐ and enantioselectivities. Based on mechanistic studies, a catalytic cycle with possible transition‐state models were proposed to explain the process.