Mechanism and Origins of Ligand-Controlled Stereoselectivity of Ni-Catalyzed Suzuki-Miyaura Coupling with Benzylic Esters: A Computational Study.

ABSTRACT: Nickel catalysts have shown unique ligand control of stereoselectivity in the Suzuki-Miyaura cross-coupling of boronates with benzylic pivalates and derivatives involving C(sp³)-O cleavage. The SIMes ligand (1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) produces the stereochemically inverted C-C coupling product, while the tricyclohexylphosphine (PCy₃) ligand delivers the retained stereochemistry. We have explored the mechanism and origins of the ligand-controlled stereoselectivity with density functional theory (DFT) calculations. The oxidative addition determines the stereoselectivity with two competing transition states, an S_N2 back-side attack type transition state that inverts the benzylic stereogenic center and a concerted oxidative addition through a

SUBMITTER: Zhang SQ 

PROVIDER: S-EPMC5607113 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature