Anions of transition metals carbonyls in nucleophilic vinyl substitution: VII. Carbonylates reaction with 1-chloro-2-(trifluoromethyl)- and 1-chloro-2-(perfluoro-tert-butyl)hexafluorocyclopent-1-enes, and with Z and E isomers of beta-chloro-alpha,beta-difluorostyrenes. Halophilic and/or nucleophilic reaction mechanism

Reactions were studied between 1-chloro-2-(trifluoromethyl)-hexafluorocyclo pent-1-ene with anions [CpFe(CO)(2)](-), [Re(CO)(5)](-), [Mn(CO)(5)](-), [C pMo(CO)(3)](-), and [CpW(CO3](-). The effect of proton donors on the compos ition of reaction products was established. The reactions with [Re(CO)(5)]( -) and [Mn(CO)(5)](-) were shown to proceed quantitatively along nucleophil ic route (S(N)2Vin) resulting in a-vinyl complexes of rhenium and manganese . The [CpMo(CO)(3)](-) and [CpW(CO)(3)](-) anions turned Out to be 10(4) ti mes less nucleophilic than [Mn(CO)(5)](-). In this case the main course of the reaction is the metal-halogen exchange with concurrent nucleophilic sub stitution. In reaction of [CpMo(CO)(3)](-) and [CpW(CO)(3)](-) with 1-chlor o-2- (trifluoromethyl)-hexafluorocyclopent-1-ene the sigma -vinyl complexes arise along an unusual autocatalytic mechanism: the reaction of carbonyl o ccurs not with the initial substrate but with pentafluoromethylcyclopent-1- ene that forms from the substrate under the action of a fluoride ion. In an extremely fast reaction of the same Substrate with [CpFe(CO)(2)]K the main process is carbonylate oxidation along unestablished mechanism. The reacti on between carbonylates and 1-chloro-2-(perfluoro-tert-butyl)hexafluorocycl opent-1-ene proceeds exclusively as metal-halogen exchange that with [Re(CO )(5)](-) furnishes anionic acyl complex cis[C9F15C(O)Re(CO)(4)Cl](-). The r eaction of Z and E isomers of beta -chloro-alpha,beta -difluorostyrenes wit h [CpFe(CO)(2)](-) in the presence of proton donors confirmed the previousl y assumed (S(N)2Vin) mechanism of nucleophilic substitution and also the in termediate formation of alkenyl carbanions in the parallel redox process.