Mechanism of the aminolysis of dimethyl phenylphosphinate: A DFT study

Abstract: The mechanism of the aminolysis of dimethyl phenylphosphinate with ammonia was investigated by the density functional theory at the B3LYP level with basis set 6-31G(d,p) in the gas phase. Single point energy evaluations were also performed for more precise energy predictions at the B3LYP and the BB1K levels with the 6-311++G(d,p) basis set. Solvent effects on the uncatalyzed process were assessed by the polarized continuum model with B3LYP/6-311++G(d,p) and BB1K/6-311++G(d,p) based on the gas-phase optimized geometries. Transition state structures and energies were determined for concerted and neutral stepwise pathways. The theoretical results show that the stepwise pathway is more favorable than the concerted process. The general base catalysis of the process was also examined. The catalytic role of a second ammonia molecule is executed by facilitating the hydrogen transfer processes and by decreasing all energy barriers. The results show that the most favorable pathway of the reaction is through the general-base-catalyzed neutral stepwise mechanism. [Copyright &y& Elsevier]