title: Generation of cycloalkynes by hydro-iodonio-elimination of vinyl iodonium salts.
abstract: Cyclohexynes can be generated efficiently from 1-cyclohexenyliodonium salts with acetate or other bases via the E2 and E1 mechanism. The observed regioselectivity of nucleophilic addition to substituted cyclohexynes conforms to the LUMO populations: the less deformed acetylenic carbon is more electrophilic. Cycloheptyne can form by the E1-type elimination via 1,2-rearrangement from cyclohexylidenemethyliodonium salt under very weakly basic conditions.
authors.affiliation: Graduate School of Material Science, Himeji Institute of Technology, University of Hyogo, Kamigori, Hyogo 678-1297, Japan. okuyama@sci.u-hyogo.ac.jp
authors.forename: Tadashi
authors.initials: T
authors.lastname: Okuyama
authors.forename: Morifumi
authors.initials: M
authors.lastname: Fujita
mesh_terms: D000114:Acetylene / Q000737:chemistry; D000480:Alkynes / Q000138:chemical synthesis*; D002244:Carbon / Q000737:chemistry; D003500:Cyclization; D007536:Isomerism; D009861:Onium Compounds / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D000480:Alkynes; D009861:Onium Compounds; D012492:Salts; D014753:Vinyl Compounds; D002244:Carbon; D000114:Acetylene