Aziridines 2-cyano- from

Aziridines can be prepared directly from double-bond compounds by photolysis or thermolysis of a mixture of the substrate and an azide. The reaction has been carried out with R = aryl, cyano, EtOOC, and RSO2, as well as other groups. The reaction can take place by at least two pathways. In one, the azide is converted to a nitrene, which adds to the double bond in a manner analogous to that of carbene addition (15-62). Reaction of NsONHC02Et/ CuO [Ns = A(/7-toluenesulfonyl-inimo)] and a conjugated ketone, for example, leads to the A-carboethoxy aziridine derivative.Calcium oxide has also been used to generate the nitrene.Other specialized reagents have also been used." ... 

The cycloaddition of aryl azides to the 17-substituted steroid- 16-enes occurred from the a-face to give a mixture of dihydrotriazole and aziridine derivatives, in a ratio which depends on the nature of the substituent at C-17113. With a methoxy substituent only the dihydrotriazole was obtained, but with a cyano substituent, the aziridine was the major product (4 1). No efforts were made to fully convert the dihydrotriazoles to the aziridines. 

Aziridines can be prepared directly from double-bond compounds by photolysis or thermolysis of a mixture of the substrate and an azide. The reaction has been carried out with R = aryl, cyano, EtOOC, and RSO2, as well as other groups. The reaction can take place by at least two pathways. 

JV-cyano]- and [7V-(methylsulfonyl)alkoxy-carbimidoyl]nitrenes, generated in situ from the corresponding azides by 300 nm UV light, convert a variety of alkenes cleanly and stereospecifically to the corresponding aziridines <89JOC3945>. 

Both diastereomeric aziridines (47), upon heating with vinylene carbonate, furnished four readily separable diastereomeric pyrrolidine esters which were transformed into both enantiomers of 1,4-dideoxy-l,4-iminoxylitol and l,4-dideoxy-l,4-iminoribitol <92TA68l>. 3-Phenyl and 3-unsubstituted 2-alkenoyl-methylaziridines synthesized via Grignard reaction from the corresponding cyano-aziridines have been thermally transformed into ring-fused pyrrolidine compounds via azomethine ylide intermediates <85JOC4ii4>. 

Some paths are available for the synthesis of cyanocyclopropyl systems from cyanoalkenes. An interesting example of this is the photoisomerization of 2-aminopropenenitrile to yield the aziridine 201. Products of fragmentation such as HCN and acetonitrile are also obtained The A-acylimine 202 is converted on irradiation into the bicyclic products 203 and 204. The route to products involves bond formation by attack of the carbonyl oxygen atom on the styryl moiety. This affords the biradical intermediate 205, where radical stabilization by the cyano group is important. Cyclization within this yields the two bicyclic compounds. The same reaction path is followed on irradiation of202 in the crystalline phase. Here, however, this path is minor (30%) and the major path affords a (2 + 2)-cycloadduct. ... 

Around the same time as the Evans work, Jacobsen and coworkers also independently reported the enantioselective alkene aziridination employing a chiral CuOTf catalyst [29]. The most effective catalyst was prepared from CuOTf with bis-((2,6-dichlorobenzylidene)-diamino)cyclohexane ligand 12, which afforded the excellent enantioselectivity in the reaction of 6-cyano-2,2-dimethylchromane with the iminoiodinane (Scheme 2.18). Reactions of styrenes also proceeded in moderate to high enantioselectivities. However, tetradentate (salen)Cu complexes such as 13 decreased both the product yields and enantioselectivities, which indicated that the existence of multiple open coordination sites on a copper center was essential to enhance the catalytic activity [30]. 

---