In this work, a mild and straightforward access to various substituted naphthalene-fused oxepines from readily available Donor-Acceptor (D-A) cyclobutanes and 2-naphthols is reported. A broad range of functional groups is tolerated during this transformation.

Abstract

A mild and straightforward access to various substituted naphthalene-fused oxepines from readily available Donor-Acceptor (D-A) cyclobutanes is reported. This method involves the Lewis acid-catalyzed reactions of D-A cyclobutanes with 2-naphthols to afford ring-opened products, which can undergo intramolecular cyclization mediated by the NBS-base system to yield corresponding naphthalene-fused oxepines. The cyclization protocol involves a nucleophilic attack of the oxygen of 2-naphthol on the newly formed electrophilic acceptor end of D-A cyclobutane.