title: Tandem insertion of halocarbenoids and lithium acetylides into zirconacycles: a novel rearrangement to zirconium alkenylidenates by β-addition to an alkynyl zirconocene.
abstract: Tandem insertion of 1,1-dihalo-1-lithio species (halocarbenoids) and lithium alkynides into zirconacyclopentenes and zirconcyclopentanes affords carbocyclic products in high yields via an unusual rearrangement that probably involves addition of an organolithium species to the β-position of a zirconium-alkyne complex to give an alkenylidene-zirconate species. A wide variety of cyclopentanoid organic structures are rapidly assembled in good yield using this multicomponent coupling. The main side reaction, which becomes exclusive in some cases, is β-hydride elimination of an intermediate cyclopentyl- or cyclopentenyl zirconocene.
authors.affiliation: School of Chemistry, University of Southampton, Highfield, Southampton, Hampshire SO17 1BJ, UK.
authors.forename: Jozef
authors.initials: J
authors.lastname: Stec
authors.forename: Emma
authors.initials: E
authors.lastname: Thomas
authors.forename: Sally
authors.initials: S
authors.lastname: Dixon
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Whitby
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003517:Cyclopentanes / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000480:Alkynes; D003517:Cyclopentanes; D009942:Organometallic Compounds; C023398:Zirconocene dichloride; D008094:Lithium; D015040:Zirconium