Reactivity of Enyne-Allenes Generated via an Alder-Ene Reaction

Org Lett. 2024 Feb 23;26(7):1299-1303. doi: 10.1021/acs.orglett.3c03696. Epub 2024 Feb 8.

Abstract

Tandem transformations of 1,3-diynyl propiolate derivatives are described. The Alder-ene reaction generates an enyne-allene, which undergoes a formal 1,7-H shift or a Diels-Alder reaction, depending on the substituent on the alkyne. A terminal or aryl-substituted alkyne promotes a 1,7-H shift to generate a new enyne-allene, which undergoes a Myers-Saito cycloaromatization followed by a 1,5-H transfer-mediated cyclization to form highly functionalized benzo-fused 6-membered cycles. The reactivity of the preformed enyne-allene shows comparable reactivity profiles.