Synthesis and Structure of Aryllithium Compounds Containing ortho-Directing (Dimethylamino)methyl and Trimethylhydrazino Substituents

The ortho-lithiated aryl compounds [2-Me2NCH2-4,6-(Me)2C6H2]2Li2·OEt2 (2) and [2-Me2N(Me)NC6H4]2Li2·TMEDA (6) have been prepared by metalation of the corresponding precursors 1 and 5. 6 is the first aryllithium derivative bearing a hydrazino group as coordinating ortho-substituent. Both organolithium compounds form in the solid a dimeric aggregate as shown by X-ray diffraction. The seven-line 13C NMR signal (1 J(7Li−13C) = 20 Hz) of the ipso-carbon atoms of 6 is in agreement with a dimeric structure of this compound in solution (C6D6) as well.