Hydrocyanation introduction

The key reaction in these syntheses was the stereoselective introduction of angular cyano groups as latent methyl groups into perhydropolycyclic a, (3-unsaturated compounds. The new hydrocyanation method developed gave excellent chemoselectivity and stereochemical control. 

Figure 2 Proposed mechanism of butadiene hydrocyanation with Ni catalysts showing the alternate insertion modes that prepare the way for introduction of the second CN group...

With the aid of this theory it is explained that just as in coloured substances the introduction of some auxochromic groups changes the colour of the substances, so in the war gases the presence of certain autotoxes can alter the type of biological action. Thus, for example, halogen introduced into the hydrocyanic acid molecule reduces the toxicity of the toxophor, —CN, and confers on the product lachrymatory properties. 

Keywords cyanides hydrocyanic acid titrimetric spectrometric alcoholic drinks. 1. Introduction... 

The second and ultimately most practical sequence involved the introduction of the C-4a angular methyl group via the Nagata hydrocyanation reaction on the enone (85) (Scheme 11). Robinson annelation between the enone (84) and... 

Hydrocyanation as apphed by Du Pont is another early example of an industrially applied catalytic reaction employing hgands [4]. The nickel catalyzed reaction uses aryl phosphite ligands for the production of adiponitrile fi om butadiene and hydrogen cyanide. The development of this process has played a key-role in the introduction of the now common study... 

The commercial introduction of hydrocyanation has been pioneered by Du Pont. The nickel complex catalyzed addition of two molecules of HCN to butadiene yielding in high regioselectivity adiponitrile is practized in two plants. 

Inspired from the usage of cyclic peptides for the hydrocyanation of carbonyls, cyclic peptides were applied to the Strecker reaction (Table 30.3) [12, 13]. Employment of 2 to the mechanistically similar Strecker reaction did not provide any asymmetric introduction In the reaction of benzaldehyde (1) catalyzed by 2, proton transfer takes place from HCN to the imidazole residue in 2. The resulting imidazolium ion can serve as an acid catalyst for the asymmetric cyanation of 1 meanwhile, in the case of the Strecker reaction, the more basic benzaldimine (17) becomes protonated directly by HCN without interaction with the catalyst [4j. Thus, replacement of the imidazole function with the more basic guanidine turned... 

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