Kinetics and Mechanisms of addition of Benzylamine to Benzylidene-1,3-indandiones in Acetonitrile

초록

Nucleophilic addition reactions of benzylamines (BA; XC6H4CH2NH2) to benzylidene -1,3-indandiones (BID; YC6H4CH=C(C=O)2C6H4) have been studied in acetonitrile at 25.0 °C. The rate is first-order with respect to BA and BID and no base catalysis is observed. The structure-reactivity behaviors (k2, rX, bX and bY) are intermediate between the two series of addition reactions of BA to b-nitrostyrene (NS) and benzylidenemalononitrile (BMN) in acetonitrile. The normal kinetic isotope effects, kH/kD > 1.0, involving deuterated BAs (XC6H4CH2ND2) are smaller than those for the reactions of NS and BMN suggesting a somewhat looser bond formation in the transition state. The reaction is predicted to proceed in a single step with concurrent Ca-N bond formation and proton transfer to Cb. A hydrogen-bonded, four-center type cyclic transition state is proposed