Nitroacetamidation alkenes

Sonication of a chloroform solution containing the alkenes, NaNOz (10 equiv), Ce(NH4)2(N03)6 (2.0 equiv), and acetic acid (12 equiv) in a sealed tube at 25-73 °C provides an excellent way to prepare nitroalkenes. For example, cyclohexene is converted into 1-nitrocyclohexene in 96% yield by this method (Eq. 2.29).56 When the reaction is carried out in acetonitrile, the carbocation intermediates are trapped by acetonitrile to give nitroacetamides in good yield.57 Analogous nitro-acetamidation is possible by using nitronium tetrafluoroborate and acetonitrile (Eq. 2.30).58... 

The structure and the stereochemistry of the 1,2- and 1,4-nitroacetamides were assigned on the basis of spectroscopic analysis and conversion of the 1,2-nitroacetamides to dihydroimidazoles. Variable syn or anti addition was observed depending on the structure of the alkene. Reduction of the nitro group to an amino function by aluminum amalgam allows stereoselective synthesis of vicinal monoacetylated diamines. 

Nitroacetamidation of Phenyl-Substituted Alkenes General Procedures ... 

Nitroacetamidation of conjugated dienes is efficient when a solution of nitronium tetrafluoroborate in acetonitrile obtained by anodic oxidation of dinitrogen tetroxide is used substantial amounts of both 1,2- and 1,4-adducts are usually obtained.34 Some conjugated nitroalkenes can be readily prepared by reaction of alkenes with sodium nitrite and iodine under mild conditions (Scheme 158).347... 

CAN-mediated nitration provides a convenient route for the introduction of a nitro group into a variety of substrates. Alkenes on treatment with an excess of sodium nitrite and CAN in chloroform under sonication afford nitroalkenes. When acetonitrile is used as the solvent, nitroacetamidation occurs in a Ritter-type fashion. However, the attempted nitroacetamidation of cyclo-pentene-1 -carboxaldehyde under similar conditions resulted in the formation of an unexpected dinitro-oxime compound. A one-pot synthesis of 3-acetyl- or 3-benzoylisoxazole derivatives by reaction of alkenes (or alkynes) with CAN in acetone or acetophenone has been reported. The proposed mechanism involves a-nitration of the solvent acetone, oxidation to generate the nitrile oxide, and subsequent 1,3-dipolar cycloaddition with alkenes or alkynes. The nitration of aromatic compounds such as carbozole, naphthalene, and coumarins by CAN has also been investigated. As an example, coumarin on treatment with 1 equiv of CAN in acetic acid gives 6-nitrocoumarin in 92% yield. ... 

---