Iridium‐Catalyzed [4+3] Cyclization of ortho‐Tosylaminophenyl‐Substituted para‐Quinone Methides with Vinylic Oxiranes/Vinyl Aziridines

Abstract

An Iridium‐catalyzed [4+3] cyclization of ortho‐tosylaminophenyl‐substituted para‐quinone methides with vinylic oxiranes or vinyl aziridines has been successfully developed. In the presence of [Ir(cod)Cl]2 and a suitable base, this unprecedented cascade reaction occurs readily in good yield (up to 97%) and high diastereoselectivity (dr>20 : 1), providing a highly efficient synthetic approach to synthetically valuable seven‐membered heterocyclic frameworks.

Recent updates on vinyl cyclopropanes, aziridines and oxiranes: access to heterocyclic scaffolds

“…Hu and co-workers 75 recently demonstrated a [4 + 3] cycloaddition reaction by utilizing p -tosylamino-substituted p -quinone methides ( p -QMs) 106 and vinyl oxiranes 20 (Scheme 36). p -QMs have been visualized as 4-atom synthons and extensively employed in [4 + 1] and [4 + 2] cascade reactions, but p -QMs in a [4 + 3] cycloannulation reaction to accomplish a higher order cyclic system still remain underdeveloped.…”

“…Scheme 36 Synthesis of benzazepines by Hu's approach 75. Scheme 35 Synthesis of benzoxepines by Shi's approach 74.…”