Reactivity of halo(pyridinium)carbenes.
The reactivity of chloro- and fluoro(N-methyl-3-pyridinium)carbenes was examined by laser flash photolysis, where the halo(pyridinium)carbenes formed ylides with pyridine, acetonitrile, and acetone. Although the halo(pyridinium)carbenes reacted within the time of the laser pulse, their relative reactivities with a series of alkenes could be obtained from quenching experiments by using carbene-pyridine ylides. Their relative order of reactivity with the alkenes and their poor overall selectivity showed that the halo(pyridinium)carbenes are strongly reactive electrophilic species. Computational studies demonstrated that the alkene (HOMO)-carbene (LUMO) interaction is predominant in halo(pyridinium)carbene-alkene reactions, supporting the electrophilic nature of these species.
Moya-Barrios
Reinaldo
R
Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4J3, Canada.
Fregeau
Benjamin M
BM
Cozens
Frances L
FL