Merging Halogen-Atom Transfer (XAT) and Copper Catalysis for the Modular Suzuki–Miyaura-Type Cross-Coupling of Alkyl Iodides and Organoborons
作者:Zhenhua Zhang、Bartosz Górski、Daniele Leonori
DOI:10.1021/jacs.1c12649
日期:2022.2.2
Suzuki–Miyaura-type cross-couplings between alkyl iodides and aryl organoborons. This process requires a copper catalyst but, in contrast with previous approaches based on palladium and nickel systems, does not utilizes the metal for the activation of the alkylelectrophile. Instead, this strategy exploits the halogen-atom-transfer ability of α-aminoalkyl radicals to convert secondary alkyl iodides into the
Irradiation of 1-phenylcycloalkenes with cyanoaromatics in methanol/acetonitrile and methanol-benzene solutions gives cis- (2) and trans-anti-Markovnikov type adducts (3), the ratio of which depends on both solvent polarity and the ring size of the starting olefins. The results of a semiempirical molecular orbital calculation show that the isomer ratio of 2/3 in acetonitrile would be determined by
molecular orbital calculation (PM3) and are discussed on the basis of the reactivities of the three kinds of intermediates involved in the reaction [cation radicals of 1 (1•+), free radicals generated by addition of MeOH to 1•+, and carbanions produced by reduction of the free radicals by anion radicals of the sensitizers]. On the basis of the results obtained by the calculation, it is concluded that the ratio