Trinitrobenzenes, carbanion reactions with

Some interesting synthetic applications have been found by Strauss for the interactions of 3,5-dinitropyridine with carbanions, as generated in situ by base-promoted CH ionization, to yield bicyclic systems by meta bridging,12 under conditions favoring a similar reaction with 1,3,5-trinitrobenzene.9 3,5-Dinitropyridine reacts with 1,3-diphenyl-2-propanone and triethylamine to give the bridged ion 76, according to Scheme 5. The reaction consists... 

Trinitrobenzene will also form adducts with carbanions generated from ketones. Thus Kimura (1953) reported that reaction with acetone or acetophenone in the presence of alkali gave dark crystalline needles and suggested structure 20. Evidence for this structure was provided... 

We have noted that both 5 2 and SnAr reactions may occur through SET processes. There is good evidence that the SnAc reaction may involve such a pathway also. Figure 8.55 shows species identified by Bacaloglu and coworkers in a fast kinetic spectroscopy study of the reaction of hydroxide ion with l-chloro-2,4,6-trinitrobenzene (picryl chloride, 71). D ending on reaction conditions, these workers could see transients ascribed to the n complex (72), an intermediate produced by single electron transfer (73), and one or more cr complexes (74, 75). In addition, evidence was obtained for the reversible formation of a phenyl carbanion (76) and a dianion (77) that probably do not lead directly to the substitution product (78). Further support for the role of SET processes in SNAr reactions comes from the detection of radical intermediates by EPR spectrometry and by correlations of reactivity with the oxidation potentials of the nucleophiles in some studies. ... 

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