ChemInform Abstract: Kinetics and Mechanism of the Aminolysis of Phenyl Cyclopropanecarboxylates in Acetonitrile

Kinetic studies of the reaction of Z-phenyl cyclopropanecarboxylates with X-benzylamines in acetonitrile at 55.0 °C have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, T±, with a hydrogen-bonded four-center type transition state (TS). These mechanistic conclusions are drawn based on (i) the large magnitude of ρX and ρZ, (ii) the normal kinetic isotope effects (kH/kD > 1.0) involving deuterated benzylamine nucleophiles, (iii) the positive sign of ρXZ and the larger magnitude of ρXZ than that for normal SN2 processes, and lastly (iv) adherence to the reactivity–selectivity principle (RSP) in all cases.