The kinetics and mechanism of the reaction of cyclopentadienylidenetriarylphosphoranes with cyano-olefins. Part V. Tricyanovinylation with cyclohexyl 1,2,2-tricyanovinyl ether

Abstract

The reaction of cyclohexyl tricyanovinyl ether (II) with cyclopentadienylidenetriphenylphosphorane (I) in benzene is catalysed by tertiary amine bases and affords triphenyl-2-(1,2,2-tricyanovinyl)cyclopentadienylidenephosphorane (III). Detailed kinetic studies of this reaction reveal a reversible nucleophilic addition of (I) to (II) as the initial step followed by an E1cB elimination of cyclohexanol via an ion-pair which involves hydrogen bonding between the conjugate acid of the base and the departing cyclohexyloxy-group.