AuBr<sub>3</sub>- and Cu(OTf)<sub>2</sub>-Catalyzed Intramolecular [4 + 2] Cycloaddition of Tethered Alkynyl and Alkenyl Enynones and Enynals: A New Synthetic Method for Functionalized Polycyclic Hydrocarbons
Cu(OTf)2 catalyst, the corresponding dihydronaphthyl ketone products 13 and 15 were obtained in high yields, respectively. The present formal [4 + 2] intramolecular cycloaddition proceeds most probably through the coordination of the triple bond at the ortho position of substrates to Lewis acids, the formation of benzopyrylium ate complex 16 via the nucleophilic addition of the carbonyl oxygen atom, the
Rhodium(II)-Catalyzed Carbocyclization Reaction of α-Diazo Carbonyls with Tethered Unsaturation
作者:Albert Padwa、M. David Weingarten
DOI:10.1021/jo991938h
日期:2000.6.1
cycloalkenone carbenoid. The cyclized carbenoid was found to undergo both aromatic and aliphatic C-H insertion as well as cyclopropanation across a tethered pi-bond. Subjection of diazo phenyl acetic acid 3-phenylprop-2-ynyl ester to Rh(II) catalysis furnished 8-phenyl-1, 8-dihydro-2-oxacyclopenta[a]indenone in high yield. The formation of this compound involves cyclization of the initially formed carbenoid
The silver salt catalyzed the CâC bond forming reaction of o-alkynylacetophenone derivatives and carbon dioxide. In this reaction, a carbonyl group and a furan skeleton were successively constructed to afford the corresponding dihydroisobenzofuran derivatives.