Hydrocyanations carbonyls

Additions include the attachment of two univalent atoms or groups (called addends) to an unsaturated system, e. g., to olefins, carbonyl groups, aromatic systems, carbenes, etc. (Rule 2.1). For example, the addition of hydrocyanic acid to the car-... 

The hydrocyanation of conjugated carbonyl compounds is a related reaction.83 Very often such a conjugated addition is carried out in aqueous conditions. For example, in the pioneer work of Lapworth, hydrocyanation of activated olefins was carried out with KCN or NaCN in aqueous ethanol in the presence of acetic acid (Eq. 10.36).84... 

The potassium cyanide complex of 18-crown-6 in benzene or acetonitrile undergoes Michael addition to unsaturated carbonyl compounds (Liotta et al., 1977). In the presence of acetone cyanohydrin, the catalytic (i.e. catalytic in potassium cyanide and crown ether) cycle for hydrocyanation shown in (21)... 

The asymmetric reactions discussed in this chapter may be divided into three different types of reaction, as (1) hydrometallation of olefins followed by the C—C bond formation, (2) two C C bond formations on a formally divalent carbon atom, and (3) nucleophilic addition of cyanide or isocyanide anion to a carbonyl or its analogs (Scheme 4.1). For reaction type 1, here described are hydrocarbonyla-tion represented by hydroformylation and hydrocyanation. As for type 2, Pauson-Khand reaction and olefin/CO copolymerization are mentioned. Several nucleophilic additions to aldehydes and imines (or iminiums) are described as type 3. 

Hydroboration, 13, 1 Hydrocyanation of conjugated carbonyl compounds, 25, 3 Hydroformylation, 56, 1 Hydrogenation catalysts, homogeneous, 24, 1... 

Oxalic acid dinitrUe Dicyanide Hydrogen cyanide Hydrocyanic acid Prussic acid Blausaure Cyanogen chloride Chloride cyanide Chloroformyl chloride Carbon oxychloride Carbonyl chloride Carbonic dichloride... 

The carbonyl sulphide is evolved at 20° C. together with hydrocyanic acid, formic acid and carbon disulphide. The gas is purified by passing through concentrated aqueous caustic potash to absorb the acid vapours, and the carbon disulphide is absorbed in a mixture of triethylphosphine, pyridine and nitrobenzene. After drying with sulphuric acid, the gas may be further purified by liquefaction or absorption in toluene.3... 

When an alkali thiocyanate is warmed with moderately concentrated sulphuric or hydrochloric acid, a yellow solid separates and carbonyl sulphide gas is evolved, which burns with a pale sulphurous flame. The yellow substance contains isoperthiocyanic acid, formed, together with hydrocyanic acid, according to the reaction ... 

Nagata, W. Voshioka, M. "Hydrocyanation of Conjugated Carbonyl Compounds in Organic Reactions" Wiley New York, N.Y., 1977, 25, 255. 

The Strecker reaction is defined as the addition of HCN to the condensation product of a carbonyl and amine component to give a-amino nitriles. Lipton and coworkers reported the first highly effective catalytic asymmetric Strecker reaction, using synthetic peptide 43, a modification of Inoue s catalyst (38), which was determined to be inactive for the Strecker reactions of aldimines (see Scheme 6.5) [62], Catalyst 43 provided chiral a-amino nitrile products for a number of N-benzhydryl imines (42) derived from substituted aromatic (71-97% yield 64->99% ee) and aliphatic (80-81% yield <10-17% ee) aldehydes, presumably through a similar mode of activation to that for hydrocyanations of aldehydes (Table 6.14). Electron-deficient aromatic imines were not suitable substrates for this catalyst, giving products in low optical purities (<10-32% ee). The a-amino nitrile product of benzaldehyde was converted to the corresponding a-amino acid in high yield (92%) and ee (>99%) via a one-step acid hydrolysis. 

Additions of Heteroatom Nucleophiles or Hydrocyanic Acid to Carbonyl Compounds... 

W. Nagata, M. Yoshioka, Hydrocyanation of Conjugated Carbonyl Compounds, Org. React. 1977, 25, 255-476. 

From what has been discussed so far in this chapter, it is clear that homogeneous catalysis has had spectacular success in imparting high enantioselectiv-ities in the making of new C-H and C-O bonds. An enantioselective method for making new C-C bonds is also potentially very useful. Hydroformylation, hydrocyanation, and carbonylation are reactions that deal with the formation of new C-C bonds. All these have been turned into enantioselective catalytic systems with varying degrees of success. Considerable success has also been... 

Two reaction paths between carbonyl compounds and nitriles catalyzed by acylium ions were calculated by the AM 1 method for two model systems according to equation 77 (E+ = HCO+, R1 = R2 = R3 = H) (a) H2C + -0-CH0 + HCN and (b) H2C = O + HC=N+CH0142. The formylated formaldehyde molecule (i.e. cation 2COCHO+) reacts with the hydrocyanic acid molecule in path a to give cation 325, which is more... 

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