56898-57-8Relevant academic research and scientific papers
Kinetics and mechanism of the anilinolyses of aryl dimethyl, methyl phenyl and diphenyl phosphinates
Dey, Nilay Kumar,Kim, Chan Kyung,Lee, Hai Whang
scheme or table, p. 717 - 724 (2011/04/16)
The reactions of Z-aryl dimethyl (1), methyl phenyl (2), and diphenyl (3) phosphinates with X-anilines in dimethyl sulfoxide at 60.0 °C are studied kinetically. Kinetic results yield the primary normal deuterium kinetic isotope effects (DKIEs) involving deuterated aniline (XC6H4ND 2) nucleophiles, kH/kD = 1.03-1.17, 1.15-1.29, and 1.24-1.51, and the cross-interaction constants (CICs), ρXZ = 0.37, 0.34, and 0.65 for 1, 2, and 3, respectively. The steric effects of the ligands (R1 and R2) on reaction rates play a role, but are relatively much smaller compared to other phosphinate systems. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed on the basis of the CICs positive signs. The dominant frontside nucleophilic attack through a hydrogen-bonded, four-center-type transition state is proposed on the basis of primary normal DKIEs and large magnitudes of the CICs for 2 and 3, while both frontside and backside attack are proposed on the basis of relatively small primary normal DKIEs for 1.
Kinetics and mechanism of the aminolysis of dimethyl and methyl phenyl phosphinic chlorides with anilines
Dey, Nilay Kumar,Hoque, Md. Ehtesham Ul,Kim, Chan Kyung,Lee, Bon-Su,Lee, Hai Whang
experimental part, p. 425 - 430 (2010/04/30)
The reactions of dimethyl phosphinic chloride (1) and methyl phenyl phosphinic chloride (2) with X-anilines have been studied kinetically in acetonitrile at 15.0 and 55.0 °C, respectively. The deuterium kinetic isotope effects (KIEs) involving deuterated aniline nucleophiles (XC 6H4ND2) are also reported for the same reactions. The obtained KIEs for 1 are secondary inverse (kH/k D=0.703-0.899H/kD=1.62-2.10> 1). A concerted mechanism involving predominantly backside nucleophilic attack is proposed for the anilinolysis of 1. A concerted mechanism involving predominantly frontside attack via a hydrogen-bonded four-center-type transition state is proposed for the anilinolysis of 2. The degree of steric hindrance is the major factor that determines both the reactivity of the phosphinates and the direction of the nucleophilic attack on the phosphinates. Copyright
