Imine compounds generation mechanisms

A new pathway for catalytic aziridination was uncovered recently by Brookhart and Templeton [30]. Standard Lewis acids such as BF3, AICI3, and TiCl4 were found to promote the reaction of ethyl diazo acetate with imines to generate the corresponding aziridines in good yield. A simple mechanism involving imine activation and alkylation by the diazo compound was advanced to account for this result (Fig. 6). 

The mechanism of the Strecker reaction has received considerable attention over its lifespan.4 The conversion of a carbonyl compound into an a-amino acid, by this method, requires a two-step process. The first step consists of the three-component condensation of cyanide and ammonia with the carbonyl compound 1 to produce an intermediate, a-aminonitrile 3. The second step involves the hydrolysis of the nitrile functional group to reveal the latent carboxylic acid 4. Whereas the second step is fairly straightforward and can be done under basic or acid conditions, the first step is more involved than one may expect. The widely accepted sequence for the first step is the nucleophilic addition of ammonia to the carbonyl carbon to produce the corresponding imine derivative 2. Once formed, this initial species is captured by the cyanide anion to generate the requisite a-aminonitrile 3. 

---