title: Computational study on mechanism of Rh(III)-catalyzed oxidative Heck coupling of phenol carbamates with alkenes.
abstract: A systematic theoretical study on the Rh-catalyzed oxidative Heck-coupling of phenol carbamates with alkenes is carried out. Two possible mechanisms (i.e. arene activation-first and alkene activation-first mechanisms) are examined. As to the C-H activation step, four mechanisms including oxidative addition, electrophilic substitution, concerted metallation-deprotonation (CMD), and σ-bond metathesis are evaluated. The calculation results indicate that the arene activation-first mechanism is more favorable for the overall catalytic cycle. This mechanism involves three steps: arene C-H activation at the position ortho to the carbamate directing group affording a six-membered rhodiacycle intermediate, insertion of the alkene double bond into the Rh(III)-aryl bond, and a final β-H elimination step to release the product and re-generate the catalyst. The rate determining step of the overall catalytic cycle is the arene C-H activation step, which is found to proceed through the acetate-assisted CMD mechanism.
authors: Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
authors: Qi
authors: Q
authors: Zhang
authors: Hai-Zhu
authors: HZ
authors: Yu
authors: Yi-Tong
authors: YT
authors: Li
authors: Lei
authors: L
authors: Liu
authors: Yong
authors: Y
authors: Huang
authors: Yao
authors: Y
authors: Fu
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002219:Carbamates / Q000737:chemistry*; D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry; D008968:Molecular Conformation; D058451:Oxidative Coupling; D019800:Phenol / Q000737:chemistry*; D011789:Quantum Theory; D012238:Rhodium / Q000737:chemistry*
chemical_list: D000475:Alkenes; D002219:Carbamates; D056831:Coordination Complexes; D019800:Phenol; D012238:Rhodium