Schlosser, ManfredHeiss, ChristopheMarzi, ElenaScopelliti, Rosario2007-03-072007-03-072007-03-07200610.1002/ejoc.200600350https://infoscience.epfl.ch/handle/20.500.14299/3562WOS:0002412044000149408Nine 1,3-dichlorobenzene congeners were selected as model compds. to assess the relative rates of proton abstraction from 4- and 5-positions ("ortho" vs. "meta" metalation). Using lithium 2,2,6,6-tetramethylpiperidide as the basic reagent, the chlorine-adjacent 4-position underwent metalation exclusively. In contrast, attack at the chlorine-remote 5-position became significant even in the case of moderately sized 2-substituents (such as dimethylamino or ethyl) when sec-butyllithium was employed. The "ortho/para" (4-/5-) ratios ranged from 80:20 to 65:35. The more pronounced "meta-orienting" effect of silicon as opposed to carbon substituents can be attributed to dissimilarities in the pi polarization of the arom. ring. [on SciFinder (R)]Carboxylation; Lithiation; Regiochemistry; Substituent effects (substituent effect on regiochem. of lithiation/carboxylation sequence of variably 2-substituted 13-dichlorobenzenes)chlorobenzene metalation regiochem substituent effecttext::journal::journal article::research article