title: Gold-catalyzed intramolecular [3+2] cycloadditions of 1-aryl-1-allene-6-enes.
abstract: Treatment of 1-aryl-1-allen-6-enes with [PPh(3)AuCl]/AgSbF(6) (5 mol %) in CH(2)Cl(2) at 25 degrees C led to intramolecular [3+2] cycloadditions, giving cis-fused dihydrobenzo[a]fluorene products efficiently and selectively. The reactions proceeded with initial formation of trans/cis mixtures of 2-alkyl-1-isopropyl-2-phenyl-1,2-dihydronaphthalene cations B, which were convertible into the desired cis-fused cycloadducts through the combined action of a gold catalyst and a Brønsted acid. Theoretic calculation supports the participation of the trans-B cation as reaction intermediate. Although HOTf showed similar activity towards several 1-aryl-1-allen-6-enes, it lacks generality for this cycloaddition reaction.
authors.affiliation: Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, ROC.
authors.forename: Rupsha
authors.initials: R
authors.lastname: Chaudhuri
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Liao
authors.forename: Rai-Shung
authors.initials: RS
authors.lastname: Liu