Palladium Negishi coupling

For purposes of completeness, palladium-catalyzed reactions for the synthesis of biaryls using zincates and arylhalides (Negishi Couplings) [254] or using sihcon compounds [255, 256] need to be mentioned. 

A kinetically controlled Negishi palladium-catalyzed coupling reaction was used in a highly stereospecific synthesis of (E)- or (Z)-a-fluoro-a,/(-unsaturated ketone (29), an intermediate to the above described depsipeptides [54], Reaction of E/Z gem-bromofluoroolefin (30) and alkoxyvinylzinc species (31) yielded (Z)-29 in 70-99% yields. When the unreacted (Z) bromo, fluoroolefin was allowed to react in tetrahydrofuran (THF) under reflux, (E)-29 was formed in up to 98% yield (Scheme 9). 

Snieckus and co-workers reported the directed lithiation of 3-furanecarboxylic acid diethylamide (6.21.), which proceeded selectively in the 2-position, and the subsequent zinc-lithium exchange. The so formed fiiranylzinc reagent underwent Negishi-coupling with 2-bromotoluene in the presence of a palladium-triphenylphosphine catalyst to give 2-(o-tolyl)furane in good yield.26... 

The scope of the Negishi-coupling is not limited to aryl and vinyl halides and sometimes acyl chlorides might also be converted to ketones by this protocol. The 2,3-dihalopyrrole derivative shown in 6.22. was converted into its 2-lithio derivative by selective lithium-halogen exchange at -78 °C. Addition of zinc chloride effected the formation of the appropriate pyrrolylzinc chloride, which was coupled with a functionalised butyroyl chloride in the presence of tetrakis(triphenylphosphino)palladium and furnished the expected 2-acylpyrrole in 61% yield.27... 

The palladium catalyzed cross-coupling of organosilicon compounds and aryl halides found only limited application with azines compared to the Suzuki or Negishi coupling. In a recent paper DeShong reported the efficient coupling of bromopyridine derivatives with aryl siloxanes (7.44.) 62 The transmetalating ability of the siloxane was enhanced by the addition of tetrabutylammonium fluoride. 

Cross-coupling reactions 5-alkenylboron boron compounds, 9, 208 with alkenylpalladium(II) complexes, 8, 280 5-alkylboron boron, 9, 206 in alkyne C-H activations, 10, 157 5-alkynylboron compounds, 9, 212 5-allylboron compounds, 9, 212 allystannanes, 3, 840 for aryl and alkenyl ethers via copper catalysts, 10, 650 via palladium catalysts, 10, 654 5-arylboron boron compounds, 9, 208 with bis(alkoxide)titanium alkyne complexes, 4, 276 carbonyls and imines, 11, 66 in catalytic C-F activation, 1, 737, 1, 748 for C-C bond formation Cadiot-Chodkiewicz reaction, 11, 19 Hiyama reaction, 11, 23 Kumada-Tamao-Corriu reaction, 11, 20 via Migita-Kosugi-Stille reaction, 11, 12 Negishi coupling, 11, 27 overview, 11, 1-37 via Suzuki-Miyaura reaction, 11, 2 terminal alkyne reactions, 11, 15 for C-H activation, 10, 116-117 for C-N bonds via amination, 10, 706 diborons, 9, 167... 

R = alkenyl, aryl, allyl, benzyl, propargyl R = alkenyl, aryl, alkynyl, alkyl, benzyl, allyl The Negishi Coupling was the first reaction that allowed the preparation of unsymmetrical biaryls in good yields. The versatile nickel- or palladium-catalyzed coupling of organozinc compounds... 

Negishi E-I, Hu Q, Huang Z, Qian M, Wang G. Palladium-catalyzed alkenylation by the Negishi coupling. Aldrichimica Acta 2005 38 71-88. 

Palladium-catalyzed coupling reactions of 2-(5-iodoisoxazol-3-yl)pyridine 274 with a variety of organometallic compounds led to derivatives 275-278 through Sonogashira, Suzuki, Negishi, and Stille reactions, respectively (Scheme 64) <20010L4185>. 

Peyrat, J.-F., Thomas, E., L Hermite, N., Alami, M., Brian, J.-D. Versatile palladium(ll)-catalyzed Negishi coupling reactions with functionalized conjugated alkenyl chlorides. Tetrahedron Lett. 2003,44, 6703-6707. 

Pannecoucke and co-workers developed a highly stereospecific synthesis of (Z)- and (E )-a-fluoroenones 66 through a kinetically controlled Negishi coupling reaction catalyzed by palladium (see Scheme 10.23) [32]. 

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