The kinetics and mechanism of the reaction of 1,1 -difluoro-2,2 -diarylethylene with amines and pK(a) measurements of amines in acetonitrile

1,1-difluoro-2,2-diphenylethylene and its para-phenyl substituted analogs have been synthesised and their reactions with piperidine in acetonitrile have been studied. The substrates are reactive only with primary and secondary amines. Tertiary amines do not react with the substrates directly, but they catalyse reactions with primary and secondary amines. Reactions with primary and secondary amines give 1-amino-1-fluoro-2,2-diarylethylenes as the initial products. The kinetics for the formation of 1-amino-1-fluoro-2,2-diarylethylene have been studied. The reaction proceeds via both amine catalysed and uncatalysed paths. The rate constants and the activation parameters for both amine catalysed and uncatalysed routes have been obtained and the rate constants show good correlation with the substituent constants, ;The catalytic rate constants of teritary amines for the reaction of 1,1-difluoro-2,2-di(4-cyanophenyl)ethylene with piperidine in acetonitrile have been obtained and correlated with the pK;In order to obtain the Bronsted relationship, the pK;The rate constants and the activation parameters for the reaction of 1,1-difluoro-2,2-di(4-cyanophenyl)ethylene with various amines have been obtained and the catalysed rate constants show a good correlation with the pK...