Using the dispersion correction density functional ωB97X-D method

the MP2 method of perturbation theory and the SMD model method of selfconsistent reaction field

the title reaction of two stable conformations(

Asp_1

and Asp_2) of Asp was investigated. The study of reaction channel and potential energy surface showed that the chiral enantiomer transition was realized by a series of Asp transition states of Hatom abstraction of hydroxyl ion(water clusters) and α-carbon

as well as the rotation of αcarboxy hydroxyl

β-carboxy hydroxyl

β-carboxyl and R-group. The intrinsic energy barrier of the rate-determining step of optical isomerization of

Asp_1

and

Asp_2

induced by α-H abstraction of hydroxyl ion and H abstraction of water molecule of αcarbon was about 27.0 kJ/mol

and the corresponding intrinsic energy barriers induced by H-atom abstraction of hydroxyl ion assisted with water molecule and H-atom abstraction of two water molecule of α-carbon were about 34.0 and 40.0 kJ/mol

respectively. It could accelerate the process of Asp chiral transition that proton attacks the α-carbon of intermediate carbon anion.