Accessing polyarene-fused ten-membered lactams via oxidative N-heterocyclic carbene (NHC)-catalyzed high-order [7 + 3] annulation

Abstract

A new oxidative N-heterocyclic carbene (NHC)-catalyzed high-order [7 + 3] annulation reaction of γ-indolyl phenols as 1,7-dinucleophiles and α,β‐alkynals with the aid of Sc(OTf)₃ is reported, enabling the highly regioselective access to unprecedented polyarene-fused ten-membered lactams bearing a bridged aryl-aryl-indole scaffold in moderate to good yields. This protocol demonstrates a broad substrate scope, good compatibility with substituents and complete regioselectivity, providing an organocatalytic modular synthetic strategy for creating medium-sized lactams.