Copper complexes generated in situ from CuCl2, alkylGrignardreagents, and 1,3‐dienes play important roles as catalytic active species for the 1,2‐hydroalkylation of 1,3‐dienes by alkylfluorides through CF bond cleavage. The alkyl group is introduced to an internal carbon atom of the 1,3‐diene regioselectively, thus giving rise to the branched terminal alkene product.
Nickel-catalyzed coupling reaction of alkyl halides with aryl Grignard reagents in the presence of 1,3-butadiene: mechanistic studies of four-component coupling and competing cross-coupling reactions
the selectivity of the nickel-catalyzed four-component coupling reactions of alkyl fluorides, aryl Grignard reagents, and two molecules of 1,3-butadiene that affords a 1,6-octadiene carbon framework bearing alkyl and aryl groups at the 3- and 8-positions, respectively, and the competing cross-coupling reaction. Both the four-component coupling reaction and the cross-coupling reaction are triggered
undergoes selective dimerization and alkylarylation with alkylfluorides and aryl Grignardreagents to give 1,6‐octadienes with alkyl and aryl groups at the 3‐ and 8‐positions, respectively, by the consecutive formation of three carbon–carbon bonds. The formation of an anionic nickel complex plays an important role in forming C−C bonds with alkylfluorides.
reaction of unactivated alkyl fluorides with alkyl Grignard reagents by a CoCl2/LiI/1,3-pentadiene catalytic system is described. The present reaction smoothly cleaved C–F bonds under mild conditions and achieved alkyl–alkyl cross-coupling even when sterically hindered tertiary alkyl Grignard reagents were employed. Since alkyl fluorides are inert toward many reagents and catalytic intermediates, the
Ni-Catalyzed Alkylative Dimerization of Vinyl Grignard Reagents Using Alkyl Fluorides
作者:Jun Terao、Hiroyasu Watabe、Nobuaki Kambe
DOI:10.1021/ja042565r
日期:2005.3.1
Alkyl halides underwent unique cross-coupling reaction with vinylmagnesium chloride in the presence of Ni catalyst to give 2-alkyl-3-butenyl Grignardreagent (1) in high yields. This reaction proceeded efficiently at 25 degrees C in THF using primary and secondary alkylfluorides. On the other hand, PhCH=CHMgBr gave double alkylative vinyl coupling product 4 in good yield as the sole coupling product