title: Charge-Transfer-Induced para-Selective sp2C-H Bond Activation of Arenes by Use of a Hypervalent Iodine Compound: A Theoretical Study.
abstract: The reaction mechanism of the C-H bond activation of toluene promoted by the hypervalent iodine compound TIPP-I(OH)OTs was investigated in detail by density functional theory calculations. Our calculations show that a plausible reaction pathway of the C-H bond activation of toluene contains two stages: (1) the ligand exchange process on TIPP-I(OH)OTs, involving the substitution of the hydroxyl group and tosyloxyl group with TfOH, and (2) the C-H bond activation of toluene promoted by the hypervalent iodine center with the assistance of the triflate anion. The second step is the rate-limiting step with a relatively low free energy barrier of 19.6 kcal mol-1in acetonitrile, which is in accord with the experimental fact that the reaction takes place at room temperature. Frontier molecular orbits and natural population analysis show that partial electron transfer from the toluene to the hypervalent iodine moiety occurs in the charge-transfer complex, resulting in the activation of the C-H bond at the para position of toluene. Further calculations show that this hypervalent iodine compound promoted C-H bond activation reaction will be effective if the substrate is electron-rich and a strong Brønsted acid is used.
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, Nanjing University , Nanjing 210093, People's Republic of China.|Office of Science and Technology, Nanjing Xiaozhuang University , Nanjing 211171, People's Republic of China.
authors.forename: Jiyang
authors.initials: J
authors.lastname: Zhao
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, Nanjing University , Nanjing 210093, People's Republic of China.
authors.forename: Shuhua
authors.identifier: 0000-0001-6756-057X
authors.initials: S
authors.lastname: Li