Strecker reaction Subject

It turned out that a-aminonitrile hydration is subject to efficient catalysis by aldehydes (22), which are already reactants of the Strecker reaction (Fig. 2). This catalytic pathway is still prevailing at 20- aM formaldehyde concentrations (21) and... 

Strecker reaction to establish a new stereocenter is subject to asymmetric induction, capable of creating either a tertiary" or quaternary carbon atom in the presence of 59. The peptido-imine 60 proves to be an excellent ligand for the Ti(IV)-mediated cyanation of aldimines. On catalysis of the bicyclic guanidine 61 the addition of HCN to A-benzhydrylaldimines affords a-amino nitrile derivatives with moderate to good ee. ... 

Initial mechanistic analysis of the Strecker reaction catalyzed by a urea-based organocatalyst (Scheme 3.18) revealed that the catalytic activity is provided by the urea functionality of structurally complex catalyst 1. However, further studies revealed a bifunchonal character of urea and thiourea-based catalysts " as well as the possibility of multiple mechanistic pathways in catalysis of nucleophile-electrophile addition reactions. " Simplified but sufficiently effective (thio)urea catalysts 4a and 4b were used in the hydrocyanation reaction (Scheme 3.19) that was subjected to a combined experimental and computational study. °... 

In another study catalyst 25d was the subject of investigation. Although this compound promoted both Strecker and Mannich reactions of imines (Scheme 12.3) the great differences in substrates imphed distinctly different reaction mechanisms. For instance, modifications to the salicylimine moiety had a significant impact on the outcome of the Strecker reaction, while having practically no affect on the Mannich reaction. Furthermore, the Mannich reaction was indifferent to the relative configuration of the diamino cyclohexyl group. This observation led to... 

CyEIC (Im) can be easily synthesized from commercially available cyclohexanone (9j). Later, Armstrong and coworkers modified the synthesis of Im [54], A Strecker reaction using 9j with aqueous sodium cyanide and ammonium chloride in diethyl ether forms a-aminonitrile, which was converted into the formamide 8g. The formamide was purified and subjected to BuOK followed by dehydration in the presence of triphosgene (Scheme 7.33). CyEIC can be stored indefinitely at -30°C however, it is highly air-sensitive and will turn dark upon exposure. 

There are expressions of uncertainty concerning the mechanism of the first step of the Strecker amino acid synthesis13-17. The reaction can proceed via the formation of an imine and subsequent nucleophilic attack of cyanide (path ). Alternatively, it has been speculated that the reaction of the aldehyde with hydrogen cyanide furnishes a cyanohydrin (path ), which then is subjected to a nucleophilic displacement of the hydroxy group by the amino function. 

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