Evidence for Carbon-Carbon Meisenheimer-Wheland Complexes between Superelectrophilic and Supernucleophilic Carbon Reagents

Proposal accepted: NMR experiments have shown unequivocally that the previously only proposed zwitterionic carbon–carbon Meisenheimer–Wheland complexes are formed in the reaction of 4,6‐dinitrobenzofuroxan (DNBF) with 1,3,5‐tris(N,N‐dialkylamino)benzenes. Increasing the temperature results in a rapid exchange between three homomeric forms of the complex (see scheme; NR2=piperidyl, morpholinyl, pyrrolidinyl).