Alkyl bromides, Negishi cross-coupling reactions

Zhou, J. Fu, G. C. Palladium-catalyzed Negishi cross-coupling reactions of unactivated alkyl iodides, bromides, chlorides, and tosylates. I. Am. Chem. Soc. 2003, 125, 12527-12530. 

Negishi cross-coupling reactions of primary and secondary alkyl bromides and iodides are achieved when Ni(COD) is employed as the catalyst in the presence of a diamine ligands such as bupybox [95],... 

Negishi-type cross-coupling reactions of primary and secondary alkyl iodides 1 and alkylzinc bromides 2 proceeded with 10 mol% of Ni(py)4Cl2/(sBu)-PyBOX 5a (entry 6) [48]. Based on calculations, an alkylNi(I)(PyBOX) complex is formed by initial SET reduction, which carries much of the spin density in the ligand, similar to Vicic s catalysts 9. Based on this result a Ni(I)-Ni(II)-Ni(III) catalytic cycle was proposed to operate. 

A direct and satisfactory procedure for tertiary alkyl-alkynyl coupling has been developed by Negishi and Baba, who used trialkynylaluminums readily obtainable from the corresponding alkynyllithiums and anhydrous AICI3 [92]. For instance, tris(l-hexynyl)aluminum underwent a remarkably clean reaction with 1-adamantyl bromide to produce cross-coupled product 96 in 96 % yield. It is noteworthy that the reaction enables novel geminal alkyl-alkynylation of ketones this reaction should find a considerable application in natural product synthesis (Sch. 60). 

Fu et al. reported Ni-catalyzed alkyl-alkyl cross-couphng reactions of diverse alkylzinc reagents with unactivated secondary alkyl halides under very mild conditions. Ni(cyclooctadiene)2 and sBu-pyridine-bis(oxazohne) (Pybox) catalyzed the Negishi coupling of various functional alkyl bromides and iodides at room... 

Zhou J, Fu GC. Cross-couplings of unactivated secondary alkyl halides room-temperature nickel-catalyzed Negishi reactions of alkyl bromides and iodides. J. Am. Chem. Soc. 2003 125(48) 14726-14727. 

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