1-Methyl-2-nitro-benzene systems

This reaction is most often carried out with R = aryl, so the net result is the same as in 14-17, though the reagent is different. It is used less often than 14-17, but the scope is similar. When R = alkyl, the scope is more limited. Only certain aromatic compounds, particularly benzene rings with two or more nitro groups, and fused ring systems, can be alkylated by this procedure. 1,4-Quinones can be alkylated with diacyl peroxides or with lead tetraacetate (methylation occurs with this reagent). 

As seen in the gitonic and vicinal systems, ammonium and related cationic centers may be components of superelectrophiles and reactive dications having the 1,3-dicationic structure. Several types of superelectrophilic aza-carbo dications have been studied in which protonated nitro groups are involved. For example, it was found that nitroethylene reacts with benzene in the presence of 10 equivalents of CF3SO3H to give deoxybenzoin oxime in 96% yield (eq 58).71 Since the reaction does not occur with only one equivalent of CF3SO3H, the formation of the /V./V -dihydroxy iminium-methyl dication 197 was proposed. In spectroscopic studies, the stable dication (199) can be directly observed by H and 13C NMR spectroscopy from solutions of l-nitro-2-methyl-l-propene (198) in CF3SO3H (eq 59). 

It was shown that a variety of readily available (Z) and ( )-enol phosphates are good stereoselective synthons. Thus as5unmetric epoxidation of these phosphates using Jacobsen s (Salen)Mn(ii) complex afforded a-hydroxy ketones in enantio-selectivity up to 96%. The reaction of enantiomerically enriched 2-methyl-2-nitro-3-(diphenylphosphatoxy)alkyl radicals (80) with tributyltin hydride and AIBN in benzene results in the formation of alkene radical/anion pairs (81) which are trapped intramolecularly, leading to pyrolidine and piperidine systems (82) with memory of stereochemistry (Scheme 17). ... 

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