title: Enyne-2-pyrone [4 + 4]-Photocycloaddition: Sesquiterpene Synthesis and a Low-Temperature Cope Rearrangement.
abstract: Intramolecular [4 + 4] photoreaction of 2-pyrones with a 1,3-enyne yields an unstable 1,2,5-cyclooctatriene product. Without a C4 pyrone substituent, 1,3-hydrogen migration converts the allene to a 1,3-diene, with a skeleton related to dactylol. With methoxy substitution, Cope rearrangement yields a nine-membered ring fused to a cyclobutane. Both structures were confirmed by X-ray crystallography. The Cope rearrangement is apparently reversible, reforming the allene which undergoes a proton shift to the more stable 1,3-diene product.
authors: Department of Chemistry, Temple University , 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.
authors: Buddha B
authors: BB
authors: Khatri
authors: Department of Chemistry, Temple University , 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.
authors: Scott McN
authors: SM
authors: Sieburth