Copper- and Nickel-Catalyzed Cross-Coupling Reaction of Monofluoroalkenes with Tertiary, Secondary, and Primary Alkyl and Aryl Grignard Reagents
作者:Hongyan Shi、Wenpeng Dai、Biyun Wang、Song Cao
DOI:10.1021/acs.organomet.7b00859
日期:2018.2.12
with tertiary, secondary, and primary alkyl and aryl Grignardreagents in the presence of a catalytic amount of copper or nickel catalyst, respectively, has been developed. The reactions proceeded smoothly at room temperature, providing (E)-alkene isomers in moderate to high yields. Plausible mechanisms of the Ni-catalyzed coupling reaction of monofluoroalkene with Grignardreagents are suggested.
Radical-Cation Vinylcyclopropane Rearrangements by TiO<sub>2</sub> Photocatalysis
作者:Naoya Maeta、Hidehiro Kamiya、Yohei Okada
DOI:10.1021/acs.joc.0c00544
日期:2020.5.15
Radicalcation vinylcyclopropane rearrangements by TiO2 photocatalysis in lithium perchlorate/nitromethane solution are described. The reactions are triggered by oxidative single electron transfer, which is followed by immediate ring-opening of the cyclopropanes to generate distonic radicalcations as unique reactive intermediates. This approach can also be applied to vinylcyclobutane, leading to the
The action of sodium hydrogen telluride on olefins
作者:Derek H.R. Barton、Luis Bohé、Xavier Lusinchi
DOI:10.1016/s0040-4020(01)87834-0
日期:1990.1
action of sodium hydrogen telluride, NaTeH, on non electrophilic carbon-arbon doublebonds has been investigated.The reaction is found to be very sensitive to the substituents on the ethylenic linkage. Whereas phenyl conjugated olefins are reduced to alkylbenzenes,the reagent adds to isolated mono and disubstituted doublebonds leading to organotellurium derivatives and with gem-disubstituted ones it leads
The catalytic activity of a highly reduced Ni catalyst in the context of a Kumada-Corriu cross coupling has been studied. This nickel complex is characterized by its high electron density, stabilized by simple olefin ligands in combination with two Li ions. Landmark reactivity has been found with this precatalyst which operates at cryogenic temperatures, thus allowing the presence of sensitive functionalities. Structural elucidation of oxidative addition intermediates and their reactivity suggest highly reduced species being operative in the C-C bond forming event.
Mechanism of the Ni(0)-Catalyzed Vinylcyclopropane−Cyclopentene Rearrangement
作者:Selina C. Wang、Dawn M. Troast、Martin Conda-Sheridan、Gang Zuo、Donna LaGarde、Janis Louie、Dean J. Tantillo
DOI:10.1021/jo901525u
日期:2009.10.16
A combination of physical organic experiments and quantum chemical calculations were used to construct a detailed mechanistic model for the Ni(0)-N-heterocyclic carbene-catalyzed vinylcyclo-propane-cyclopentene rearrangement that involves a mutistep oxidative addition/haptotropic shift/reductive elimination pathway. No evidence for the intermediacy of radicals or zwitterions was found. The roles of substituents on the vinylcyclopropane substrate and variations in the ligands on Ni were evaluated. It is postulated that bulky carbene ligands facilitate formation of the active catalyst species.