Gold-Catalyzed Cyclizations of (<i>o</i>-Alkynyl)phenoxyacrylates with External Nucleophiles: Regio- and Stereoselective Synthesis of Functionalized Benzo[<i>b</i>]oxepines

Abstract

A catalytic approach to benzo[b]oxepines with high stereoselectivity by Au-catalyzed cyclization of (o-alkynyl)phenoxyacrylates with various nucleophiles under mild reaction conditions has been developed. Notably, the use of vinyl ether instead of alcohol could afford the same benzoxepines. The reaction may proceed by Au-catalyzed oligomerization of vinyl ether to release the alcohol, which then reacts with (o-alkynyl)phenoxyacrylates to furnish the benzoxepines.