Abstract The lithiation/boronation of 1, 4-dihalobenzenes (Hal= F, Cl, Br) bearing various functional groups in the 2-position was investigated using lithium diisopropylamide (LDA) as the metalating agent and trialkyl borate B (OR) 3 (R= Et, iPr) as the electrophile. It was demonstrated that sufficient steric hindrance precludes effective ortho-lithiation at the 3- position. In such cases, a strong meta-directing effect of an oxygen-or sulfur-based ...
