Carbonylative Negishi coupling

The palladium-catalyzed carbonylative Negishi coupling of ort/w-disubstituted aryl iodides with an alkynyl zinc reagent was investigated by Martin and colleagues in 2008 [34]. Alkynones were produced in good yields under mild conditions (Scheme 4.42). 

Chen and Wang described a nickel-catalyzed carbonylative Negishi coupling reactions [82]. In the presence of a catalytic amount of nickel chloride and 4,4 -dimethoxyl-2,2 -bypyridyl under carbon monoxide atmosphere, various enones were produced from enol triflates and diorganozinc reagents (Scheme 4.44). They demonstrate that the rate of CO insertion is increased by the addition of lithium or magnesium halides and the use of polar solvents. Alkenyl iodides can also be used instead of enol triflates. 

Intramolecular carbonylative cross-coupling involving enolizable GH-acidic fragments has been described by Negishi et al. In this case, trapping of acylpalladium intermediate is effected formally by enolate, either with carbon or oxygen center (Scheme 28). 

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... 

Elimination. ( , )-1,3-Dienamines are obtained from (Z)-4-methoxy-2-aIkenyl-amines by treatment with BuLi (or NaHMDS). Elimination of MeOH is stereoselective. A preparation of trifluoromethylallenes from l,l-dichloro-3,3,3-trifluoropropen-2-yl tosylate involves treatment with BuLi to generate lithium 3,3,3-trifluoropropynide, which is used for reaction with carbonyl compounds and then Negishi coupling. ... 

Jackson and colleagues reported an apphcation of the carbonylative Negishi reaction for the synthesis of Kynurenine derivatives [79, 80]. More specifically, an amino acid-derived organozinc reagent was coupled with aryl iodides under one atmosphere of CO (Scheme 4.41). 

Scheme 4.43 Pd-catalyzed caibonylative Negishi coupling of unsaturated carbonyls...

Scheme 9.38 Carbonylative Negishi cross-coupling to give the sterically encumbered alkynyl aryl ketone 107 en route to luteolin 108 [288].

Carbon-heteroatom double bonds can also participate in this reaction. These include both carbonyl compounds (Scheme 11.37) and imines (Scheme 11.38). Addition to aldehydes is co-catalysed by tin(II) or indium(III) salts. Under these conditions, tetrahydrofiirans are obtained. The presence or absence of the co-catalyst can also switch the reaction from one mode to another (Scheme 11.39). An indium cocatalysed cycloaddition to a 7-pyrone aldehyde 11.117 was used in a synthesis of aureothin 11.122 and A-acetylaureothamine 11.123 (Scheme 11.40). Cross-metathesis of the exo-cyc ic alkene 11.118 allowed a subsequent Suzuki coupling with a gem-dibromide 11.120 that showed the expected selectivity (Section 2.1.4.2). This reaction required the use of thallium ethoxide as the Lewis base to suppress the formation of side products. A Negishi coupling completed the synthesis of aureothin 11.122. Reduction and acylation of the nitro group yielded A-acetylaureothamine 11.123. The latter compound is active digainst Helicobacter pylori, a bacterium behind stomach ulcers. 

The first palladium-catalyzed copolymerization of carbon monoxide (CO) with olefins was described in 1982 [11], and as a consequence, carbonylative coupling reactions with alkenes were reported soon after. Notably, it was Negishi and Miller who discovered the first two examples of intramolecular carbonylative Heck reactions of 1-iodopenta-1,4-dienes by applying stoichiometric amounts of palladium [12]. 5-Methylenecyclopent-2-enones as the products were produced in moderate yields (Scheme 7.1). 

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