Annulation Reactions of Isoquinolinium Ylides with Sulfamate-Derived Cyclic Imines toward Polycyclic 1,3-Benzoxazepine Heterocycles

Abstract

A dearomatization-guided and (3+2) cycloaddition-triggered annulation reaction of in situ formed isoquinolinium ylides with sulfamate-derived cyclic imines is reported, offering a cogent synthesis of tetracyclic 1,3-benzoxazepine frameworks in high yields. The protocol features successive ring-forming and ring-breaking events in a cascade fashion and is also scalable.