Nickel-catalyzed cross-coupling of unactivated alkyl halides and tosylate carrying a functional group with alkyl and phenyl Grignard reagents
作者:Surya Prakash Singh、Jun Terao、Nobuaki Kambe
DOI:10.1016/j.tetlet.2009.07.094
日期:2009.10
primary and secondaryalkylGrignardreagents undergo cross-coupling with alkyl bromides, iodide, and tosylate carrying a functional group such as amide, ester, and ketone at 0 °C in THF. The present procedure provides a simple, convenient, and practical method for construction of carbon chains in the presence of various functional groups. PhMgBr also gave the corresponding coupling product in a moderate
A convenient method for synthesizing elongated aliphatic esters fromalkenes is reported. An (alkoxycarbonyl)methyl radical species is generated upon visible‐light irradiation of an ester‐stabilized phosphorus ylide in the presence of a photoredox catalyst. This radical species adds onto the carbon–carbon double bond of an alkene to produce an elongated aliphatic ester.
A New Efficient Catalytic System for the Chemoselective Cobalt-Catalyzed Cross-Coupling of Aryl Grignard Reagents with Primary and Secondary Alkyl Bromides
The cobalt-catalyzed alkylation of aromatic Grignard reagents is performed in good yields by using a new simple and efficient catalytic system: CoCl(2)/TMEDA (1:1). Primary and secondary cyclic or acyclic alkyl bromides were used successfully. The reaction is highly chemoselective since ester, amide, and keto groups are tolerated. The procedure is inexpensive and very easy to carry out on a larger scale.
Functional Group Tolerant Kumada−Corriu−Tamao Coupling of Nonactivated Alkyl Halides with Aryl and Heteroaryl Nucleophiles: Catalysis by a Nickel Pincer Complex Permits the Coupling of Functionalized Grignard Reagents
作者:Oleg Vechorkin、Valérie Proust、Xile Hu
DOI:10.1021/ja9027378
日期:2009.7.22
A nickel(II) pincer complex [((Me)NN(2))NiCl] (1) catalyzes Kumada-Corriu-Tamao crosscoupling of nonactivated alkyl halides with aryl and heteroaryl Grignard reagents. The coupling of octyl bromide with phenylmagnesium chloride was used as a test reaction. Using 3 mol % of 1 as the precatalyst and THF as the solvent, and in the presence of a catalytic amount of TMEDA, the coupling product was obtained