title: Highly active Au(I) catalyst for the intramolecular exo-hydrofunctionalization of allenes with carbon, nitrogen, and oxygen nucleophiles.
abstract: Reaction of benzyl (2,2-diphenyl-4,5-hexadienyl)carbamate (4) with a catalytic 1:1 mixture of Au[P(t-Bu)2(o-biphenyl)]Cl (2) and AgOTf (5 mol %) in dioxane at 25 degrees C for 45 min led to isolation of benzyl 4,4-diphenyl-2-vinylpyrrolidine-1-carboxylate (5) in 95% yield. The Au(I)-catalyzed intramolecular hydroamination of N-allenyl carbamates tolerated substitution at the alkyl and allenyl carbon atoms and was effective for the formation of piperidine derivatives. gamma-Hydroxy and delta-hydroxy allenes also underwent Au-catalyzed intramolecular hydroalkoxylation within minutes at room temperature to form the corresponding oxygen heterocycles in good yield with high exo-selectivity. 2-Allenyl indoles underwent Au-catalyzed intramolecular hydroarylation within minutes at room temperature to form 4-vinyl tetrahydrocarbazoles in good yield. Au-catalyzed cyclization of N-allenyl carbamates, allenyl alcohols, and 2-allenyl indoles that possessed an axially chiral allenyl moiety occurred with transfer of chirality from the allenyl moiety to the newly formed stereogenic tetrahedral carbon atom.
authors.affiliation: P. M. Gross Chemical Laboratory, Duke University, Durham, North Carolina 27708-0346, USA.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Zhang
authors.forename: Cong
authors.initials: C
authors.lastname: Liu
authors.forename: Robert E
authors.initials: RE
authors.lastname: Kinder
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Han
authors.forename: Hua
authors.initials: H
authors.lastname: Qian
authors.forename: Ross A
authors.initials: RA
authors.lastname: Widenhoefer