Cross-coupling reactions alkyl halides with Grignard reagents

Cross-coupling reaction of alkyl halides with grignard reagents in the presence... 

CROSS-COUPLING REACTION OF ALKYL HALIDES WITH GRIGNARD REAGENTS IN THE PRESENCE OF 1,3-BUTADIENE CATALYSED BY NICKEL, PALLADIUM, OR COPPER... 

Very recently, Hu [129] has shown that cross-coupling reactions of alicyclic alkyl halides with Grignard reagents catalyzed with nickel catalysts exhibit a remarkable diastereoselectivity which depends markedly on the structure of the catalyst. Nickamine (45) has better performance than a second catalyst, 46 bearing a bidentate amino-amido ligand. The influence of the catalyst structure suggests that the diastereoselectivity of the reaction originates in the coordination sphere of the metal, that is, after capture of the radical by the transient Ni(III) intermediate has taken place, as shown in Scheme 2.19. 

Cross-Coupling Reaction of Alkyl Halides with Grignard Reagents Catalyzed by Ni, Pd, or Cu Complexes with n-Carbon Ligand(s) Terao, J. Kambe, N. Acc. Chem. Res. 2008,... 

Oxidative addition of the carbon-halogen bond is a well-documented reaction for Group 10 transition metal complexes, but it is relatively limited for ruthenium. The example given here involves the reversible oxidative addition of allyl halide to RuCp(CO)2X to produce RuCp(p -allyl)X2 [78]. Oxidative addition of allyl halide to a Ru(0) complex Ru(l,5-COD)(l,3,5-COT) is also reported, but the product yield was poor [79]. Nevertheless, a catalytic Heck-type alkenylation of bromostyrene with methyl acrylate by Ru(l,5-COD)(l,3,5-COT) proceeded smoothly [80]. A cross-coupling reaction of alkenyl halide with Grignard reagents or alkyl lithium also pro-... 

While alkynyllithiums react with primary alkyl halides in the presence of diamines or HMPA to afford the coupled products [35], this reaction proceeds slowly in the absence of these additives, even at elevated temperature. Luh has described a Pd/PPh3 catalyst that facilitates the cross-coupling of alkynyllithiums and alkynyl Grignard reagents with primary alkyl bromides and iodides (e.g.,Eq.l5) [37]. 

Scheme 29 Iron-catalyzed cross coupling reaction of aryl Grignard reagents with alkyl halides...

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