Carbon monoxide reaction with nitriles

Other acid-catalysed addition reactions include reaction with nitriles (Ritter reaction), formaldehyde (Prins reaction) and carbon monoxide and water (Koch reaction). These reactions are normally catalysed by concentrated sulphuric acid. Extensive isomerization occurs and may even lead to quaternary compounds of the type RC(CH3)XR where X is the new functional group introduced into the molecule. Homogeneous catalysts have been developed which give simpler products without extensive isomerization. 

Carbon monoxide, hydrogen cyanide, and nitriles also react with aromatic compounds in the presence of strong acids or Friedel-Crafts catalysts to introduce formyl or acyl substituents. The active electrophiles are believed to be dications resulting from diprotonation of CO, HCN, or the nitrile.64 The general outlines of the mechanisms of these reactions are given below. 

Drauz,. K. Burkhardt, O. Beller, M. Eckert, M. (Degussa-Huels A.-G., Germany). Amidocarbonylation procedure and catalysts for the production of N-acylaminoacids from the reaction of carbon monoxide with aldehydes and amides or nitriles. Ger. Offen. 2000 DE 10012251. Chem. Abstr. 2000, 134, 56964. 

Small Quantities. Oxalic acid is decomposed to carbon dioxide, carbon monoxide, and water by heating in concentrated sulfuric acid. Wear nitrile rubber gloves, laboratory coat, and eye protection. In the fume hood, oxalic acid (5 g) is added to 25 mL of concentrated sulfuric acid in a 100-mL round-bottom flask. Using a heating mantle, the mixture is maintained at 80-100°C for 30 minutes. The sulfuric acid can be re-used for the same procedure because the only nonvolatile product of the decomposition is a small quantity of water. Otherwise, allow the reaction mixture to cool to room temperature, and then slowly and carefully pour the sulfuric acid into a pail of cold water (or cold water and ice), neutralize with sodium carbonate, and wash into the drain.6... 

Nitrile derivatives of the metal carbonyls have been discussed together with other nitrogen donor molecules in a number of contexts. Much of the early work has been reviewed by Manuel 337) in his article on Lewis base-metal carbonyl complexes in Volume 3 of this series, and by Stroh-meier 436) in his review of photochemical substitution reactions. In general, nitriles are weaker Lewis donors than phosphorus and nitrogen bases 436), but compared to carbon monoxide, better electron donors but poorer acceptors 427). Force constants and assignments for a series of complexes [(MeCN)jjM(CO)g J (M = Cr, Mo, W) were studied 165, 228, 296) and... 

Hydrogen and carbon monoxide were lost from the latter to form the Fe" complexes (XCIV x=0). The appearance of an absorption assigned to indicated the formation of an unstable Fe—H intermediate. Carbonyla-tion of (XCIV X = 0) gave the red cis complex (XCIV x = 2) 344). Noncoordinate irnine groups were postulated for the product (XCV R =/)-MeOC6H4) from the reaction of Fe2(CO)9 and p-methoxythio-benzamide, which contrasts with the normal reaction of iron carbonyls with primary amides and thioamides, w hich proceed to nitriles 16). 

The uranium-carbon multiple bond has an extensive insertion chemistry with polar unsaturated molecules including carbon monoxide, nitriles, isocyanides,and isocyanates. Metal carbonyls also insert into this bond to form metallaphosphoniumenolates, which undergo novel reactions... 

The reaction of nitriles with carbon monoxide, carbonyl compounds, carboxylates, ketenes, 1-aminoal-kynes and carbenes has been reviewed recently... 

In Older to avoid the handling of poisonous hydrogen selenide, two other useful syntheses have been devised. One method uses the reaction of aromatic nitriles with aluminum selenide in the presence of pyridine, triethylamine and water (Scheme 24), while the other is performed by the reaction of nitriles with selenium, carbon monoxide and water in the presence of triethylamine (Scheme 25). These methods are exceedingly convenient in terms of manipulation without the isolation of hydrogen selenide for the preparation of selenoamides. Using these methods, a variety of aromatic and heterocyclic selenoamides can be obtained from the corresponding nitriles in high yields. 

The Pauson-Khand reaction is a powerful tool for the synthesis of cyclopentanones, 246, from a>-alkenylacetylenes, 245, and carbon monoxide.176 Enyne cyclization has been catalyzed with nitriles using catalytic (77S-CsH5)2Ti(PMe3)2 95177-179 and other variants have since been discovered where the desired cyclopentenones can be directly prepared from the enyne and CO using (77S-CsHs)2Ti(CO)2 68 (Scheme 33) 176,180-184 Addition of PMe3 to the latter reaction mixture has proved to be beneficial. Stoichiometric reactions established that the initial step in the catalytic cycle is reductive coupling of the alkyne and the olefin to form the titanacycle. Carbon monoxide insertion followed by reductive elimination generates the observed product. 

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