Synthesis and structure of aryllithium compounds containing ortho-directing (dimethylamino)methyl and trimethylhydrazino substituents

The ortho-lithiated aryl compounds [2-Me(2)NCH(2)-4, 6-(Me)(2)C6H2]Li-2(2) . OEt(2) (2) and [2-Me(2)N(Me)NC6H4]Li-2(2) . 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 C-13 NMR signal ((1)J((Li-13C)-Li-7) = 20 HZ) Of the ipso-carbon atoms of 6 is in, agreement with a dimeric structure of this compound in solution (C6D6) as well.