Catalytic Asymmetric [8+3] Annulation Reactions of Tropones or Azaheptafulvenes with <i>meso</i>‐Aziridines

Abstract

Abstract Highly enantioselective [8+3] high‐order cycloaddition reactions of tropones or azaheptafulvenes with meso ‐aziridines were achieved by a desymmetrization/annulation process in the presence of chiral N , N′ ‐dioxide/Mg(OTf) 2 complex. The corresponding tetrahydrocyclohepta[ b ][1,4]oxazines and tetrahydro‐1 H ‐cyclohepta‐ [ b ]‐pyrazines were obtained in good yields (66–98 %) with excellent diastereo‐ and enantioselectivities (&gt;19:1 d.r., 90–96 % ee ). A possible transition state model was proposed to elucidate the origin of chiral induction based on the control experiments and X‐ray crystal structure of the catalyst.