Nickel-catalysed reactions carbonylation

The phase-transfer catalysed reaction of nickel tetracarbonyl with sodium hydroxide under carbon monoxide produces the nickel carbonyl dianions, Ni,(CO) 2- and Ni6(CO)162, which convert allyl chloride into a mixture of but-3-enoic and but-2-enoic acids [18]. However, in view of the high toxicity of the volatile nickel tetracarbonyl, the use of the nickel cyanide as a precursor for the carbonyl complexes is preferred. Pretreatment of the cyanide with carbon monoxide under basic conditions is thought to produce the tricarbonylnickel cyanide anion [19], as the active metal catalyst. Reaction with allyl halides, in a manner analogous to that outlined for the preparation of the arylacetic acids, produces the butenoic acids (Table 8.7). 

The reaction of alcohols with CO can also be catalysed by palladium iodides, and various ligands or solvents. Acetic acid is prepared by the reaction of MeOH with CO in the presence of a catalyst system comprising a palladium compound, an ionic iodide compound, a sulfone solvent at conditions similar to those of the rhodium system (180 °C, 60 bar), and, in some cases, traces of a nickel-bipyridine compound were added. Sulfones or phosphine oxides play a stabilising role in preventing metal precipitation [26], Palladium(II) salts catalyse the carbonylation of methyl iodide in methanol to methyl acetate in the presence of an excess of iodide, even without amine or phosphine co-ligands platinum(II) salts are less effective [27],... 

A nickel-catalysed alkyne insertion between the carbonyl carbon and the -carbon of the cyclobutanone was achieved by combining a ketone-alkyne coupling reaction with a /3-carbon elimination process (Scheme 79).121 The reaction uses cyclobutanones as a four-carbon unit and provides access to substituted cyclohexenones. 

A number of other carbonyl compounds can also be decarboxylated, including cyclic anhydrides. Catalysed by nickel, this reaction is a decarbonylation-decarboxylation leading to an alkene (Scheme 4.99). ... 

Earlier in 2007, the same authors reported the first example of intermo-lecular enantioselective nickel-catalysed reductive coupling of 1,3-dienes with carbonyl compounds. As shown in Scheme 3.28, the reaction of... 

Enantioselective Nickel-Catalysed a-Heterofunctionalisation, and a-Arylation/Alkylation Reactions of Carbonyl Compounds... 

Asymmetric carbonyl allylation represents one of the most important types of reaction in current organic synthesis. In this context, Morken and Zhang described enantioselective nickel-catalysed allylation of dienals in 2009. ... 

In the context of enantioselective nickel-catalysed multicomponent reactions, many excellent results have also been achieved. For example, three-component reactions between 1,3-dienes, carbonyl compounds... 

The sixth chapter of the book was devoted to advances in enantioselective nickel-catalysed a-functionalisation, and to a-alkylation/arylation reactions of carbonyl compounds. A prochiral carbonyl compound can be activated toward electrophilic substitution via the formation of an enol or enolate intermediate, generating a tertiary or quaternary centre at the a-carbon. The use of a non-carbon electrophile leads to heterofunctionalised products, while that of carbon electrophiles affords a-arylated/alkylated carbonyl compounds, and the generation of a new stereogenic centre in these reactions... 

A text and the proceedings of a conference describe catalytic applications of transition-metal compounds in organic synthesis. New developments in nickel-catalysed carbon-carbon bond formation and the coupling of alkyl groups using transition-metal catalysts have also been reviewed. [TiGp2Cl2] catalyses reaction (23) (n = 1 or 2, X = Mg) carbonylation of the product followed by hydrolysis gives y- or 5-lactones (i.e. X = CO). ... 

Shingare and co-workers have presented for the first time a successful implementation of ultrasound irradiation for the rapid synthesis of a-hydroxy phosphonates (521) and a-amino phosphonates (525) under solvent-free conditions from triethyl phosphite (524), aromatic aldehydes (523) and amines (522) using camphor sulfonic acid (CSA) (Scheme 130). One-pot, three-component Kabachnik-Fields synthesis of a-aminophos-phonates (529) from carbonyl compounds (526), primary amines (527), and dibenzyl/dimethyl/diethyl substituted phosphites (528) has been carried out in high yields, using H-beta zeolite as a reusable catalyst (Scheme 131). Zhang and co-workers have developed the nickel-catalysed Arbuzov type phosphonylation to afford phenyl substituted phosphonates (532) in the reaction of aryl triflates (530) with triethyl phosphite (531), in which KBr, as an additive, promoted the Sn2 catalytic step (Scheme 132). ... 

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