Nitroallylation

Conversion of nitroallyl compounds into vinyl nitrile derivatives... 

Selected examples of nitriles from nitroallyl compounds... 

Comparison of the standard potentials of the radical anion of three a-nitrocumenes (o -nitrocumene, /7-cyano-a-nitrocumene and p-nitro-a-nitrocumene) revealed that the nitroallyl portion occurs in (90a) and (90b), while in (90c) the electron is added to the nitrophenyl group. It was concluded that homolytic cleavage takes place for the radical anions of (90a) and (90b) to give nitrite and the cumyl radical whereas the cleavage of radical anion (90c) is heterolytic. ... 

Among the halides that react through this process are unactivated aromatic and heteroaromatic halides, vinyl halides, activated alkyl halides [nitroalkyl, nitroallyl, nitro-benzyl and other benzylic halides substituted with electron-withdrawing groups (EWG) as well as the heterocyclic analogues of these benzylic systems] and non-activated alkyl halides that have proved to be unreactive or poorly reactive towards polar mechanisms (bicycloalkyl, neopentyl and cycloalkyl halides and perfluoroalkyl iodides). 

Examples of such three-carbon synthons are 2-nitro-2-propen-l-yl acetates and piva-lates, which have been developed by Seebach and coworkers57,58 as reagents for [3 + 3] cyclizations with cyclic and acyclic ketone enamines. After workup these reactions give 4-nitrocyclohexanones. With enamines from prolinol methyl ether and cyclic ketones, enantiomerically pure compounds were obtained58. An example of such a [3 + 3] cyclization is the synthesis of bicyclic nitroketone 99 from nitroallylic ester 97 and enamine 98 (equation 18). 

The mechanism of this cyclization involves a conjugate addition of the enamine (100) to the nitroallyl ester (101) to give 102, which on elimination produced 103. The immonium salt 103 undergoes proton transfer to give enamino nitro olefin 104, which cyclizes to an enamine (107) via 105 and 106. Hydrolysis of 107 produces the ketone (108). Depending on the reaction conditions and the structure of the enamine and nitroolefin components employed, intermediates can be isolated (equation 19). 

SMP enamines have a very broad range of applications as d synthons. Cyclohexanone SMP enamine can be used for efficient Michael additions to nitroalkenes, Knoevenagel acceptors, and to a nitroallylic ester in a [3 + 3] carbocyclization with excellent stereoselectivities (eq 1). The synthesis of y-oxo-a-amino acids using SMP enamines has been developed (eq 2). ... 

C -Nitro polymers from monomers with a vinyl group Nitroallyl acetate polymer Ethyl nitroacrylate Nitroelhyl acrylate Nilroethyl methacrylate Trinitroethyl acrylate Dinitropropyl acrylate (DNPA)... 

CNITRO POLYMERS FROM MONOMERS WITH A VINYL GROUP Nitroallyl Acetate Polymer 3 ... 

Syntheses of 4-amino-3,5-dinitropyrazoles were achieved from four different starting materials (14JHC1621). 1,3-Di-substituted pyrazoles 32 were smoothly synthesized from the copper-catalyzed cascade reactions of oxime acetates 31, aniline, and paraformaldehyde (14CC14793). Nitroallylic acetates 33 and N-tosylhydrazine underwent cascade regioselective reaction to give ethyl pyrazole-5-carboxylates 34 (14T795). 

---