Oximes, Hydroxylamines, and Other Nitrogen Derivatives

The conversion of nitroalkanes to ketoximes can be achieved by the reduction with Zn in acetic acid,112 or Fe in acetic acid.113 Nitroalkenes are direcdy reduced into saturated ketoximes by these reagents, which are precursors for ketones (see Section 6.1.4 Nef reaction). Reduction of 3-O-ace-ty lated sugar 1 -nitro-1 -alkenes with Zn in acetic acid gives the corresponding 2,3-unsaturated sugar oximes in high yield, which is a versatile route to 2,3-unsaturated sugar derivatives (Eq. 6.58).114 

As shown in Eq. 6.59, Rapoport has prepared sinefungin, nucleoside antibiotics, via nitro-aldol reaction, dehydration, and reduction with Zn in acetic add.115a [i-Nitrostyrenes are selectivity reduced to the corresponding oximes by indium metal in aqueous methanol under neutral conditions.11515 

The conversion of nitroalkenes into the oximes can be achieved by electrochemical reduction (Eq. 6.60).11 s 

Reaction of the salts of primary and secondary alky Initio compounds with diborane in THF solution at 25 °C yields the corresponding hydroxylamines.117 Kabalka has reported the reduction of nitroalkenes to hydroxylamines or amines with a variety of borane and borohydride reagents (Eq. 6.61).118 

Deoxygenation from nitroalkanes is possible by other various reagents, including TiCl3,119 Me3SiI,63 carbon disulfide in the presence of base,120 Me3SiSiMe3,121 and Sn(SPh)2-PhSH-Et3N (Eq. 6.62).122 

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