title: Rhodium(I)-catalyzed cyclization of allenynes with a carbonyl group through unusual insertion of a C-O bond into a rhodacycle intermediate.
abstract: Rhodium(I)-catalyzed cyclization of allenynes with a tethered carbonyl group was investigated. An unusual insertion of a CO bond into the C(sp(2) )-rhodium bond of a rhodacycle intermediate occurs via a highly strained transition state. Direct reductive elimination from the obtained rhodacyle intermediate proceeds to give a tricyclic product containing an 8-oxabicyclo[3.2.1]octane skeleton, while β-hydride elimination from the same intermediate gives products that contain fused five- and seven-membered rings in high yields.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Nishi 6, Kita 12, Kita-ku, Sapporo 060-0812 (Japan) http://gouka.pharm.hokudai.ac.jp/FSC/jpn/page/top_page.htm. biyo@pharm.hokudai.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Oonishi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yokoe
authors.forename: Akihito
authors.initials: A
authors.lastname: Hosotani
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sato
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*
chemical_list: C000591321:8-oxabicyclo(3.2.1)octane; D000480:Alkynes; D019086:Bridged Bicyclo Compounds, Heterocyclic; D009942:Organometallic Compounds; D012238:Rhodium
keywords: alkynes; allenes; carbonyl compounds; cycloadditions; rhodium