Zinc organometallic nucleophile

Nucleophilic addition of zinc organometallic reagents to other C=N bond-containing... 

Nitrones have a more reactive C=N bond toward nucleophilic addition compared to imines. In spite of this fact, there have been only a limited number of studies on the nucleophilic addition reactions of nitrones, particularly organometallic reagents.352-355 During the last decade, research related to reactions of nitrones with zinc-containing reagents was essentially focused on (i) dialkylzinc-assisted alkynylations356-358 and vinylations359 of nitrones, (ii) catalytic asymmetric nucleophilic additions to the C=N bond,360-364 and (iii) nitrone allylations by allylzinc halides.365,366... 

Acetaldehyde is the product of the Wacker process. At the end of the fifties oxidation of ethene to ethanal replaced the addition of water to acetylene, because the acetylene/coal-based chemistry became obsolete, and the ethene/petrochemistry entered the commercial organic chemicals scene. The acetylene route involved one of the oldest organometallics-mediated catalytic routes started up in the 1920s the catalyst system comprised mercury in sulfuric acid. Coordination of acetylene to mercury(II) activates it toward nucleophilic attack of water, but the reaction is slow and large reactor volumes of this toxic catalyst were needed. An equally slow related catalytic process, the zinc catalysed addition of carboxylic acids to acetylene, is still in use in paint manufacture. 

Early investigations on organometallic (—)-sparteine complexes concern the nucleophilic addition of lithium, magnesium and zinc complexes onto carbonyl compounds, utilization in polymerization and also NMR spectroscopic investigations ... 

Vinyl isoxazolines 48 can be prepared by cycloaddition of nitrile oxide to 1,3-butadiene. An alternative synthetic approach has been recently described. The method is based on domino nucleophilic addition-anionic C-O-heterocyclization of nitrile oxides with allyl organometallics derived from trans-1,4-dihalobutene and a metal such as zinc, magnesium or indium. In the case of indium an aqueous media could be used <07SL1449>. 

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