Theoretical Study of Phosphoryl Transfer Reactions

The energetics and transition state (TS) structures of the reactions of six substrates, R1R2P(=O or S)Cl-type where R-1 = R-2 = Me and/or MeO, with ammonia in acetonitrile are theoretically investigated at the level of CPCM-MP2/6-31+G(d) and CPCM-MP2/6-311+G(3df,2p). The degrees of distortion of TS from the ideal trigonal bipyramidal pentacoordinate, Delta delta(not equal b), for a backside and Delta delta(not equal f) for a frontside attack, are calculated. The results of calculation suggest that the feasibility of a frontside attack for P=S is greater than that for P=O system when the two ligands, R-1 and R-2, becomes larger. The experimental and calculated results of anilinolyses of R1R2P(=O or S)Cl-type show the consistent tendencies.