Catalyst- and Additive-Free Methodical Ring Expansion Protocol to Access Benzooxepino-Fused Pyrroles.

An efficient metal-free, additive-free synthetic method was developed to access benzooxepino-fused pyrrole derivatives from alkynyl substituted aziridines. In this organic transformation, two new C-C bonds were formed via initial cleavage of C-C bond of aziridine ring by in situ generated azomethine ylides. Moderate to excellent yields of benzooxepino-fused pyrroles were obtained atom economically in the presence of t-BuOH in one-pot.