Application of organolithium and related reagents in synthesis, part 24. Synthetic strategies based on aromatic metallation. A concise regiospecific conversion of benzoic acids into 2-(1-aryl-2-methoxycarbonylethyl)benzoic acids

The synthesis of the 3-arylphthalides 3 via metallation (BuLi) of the benza nilides 1 and subsequent reaction of the generated bis-lithiated anilides 2 with aromatic aldehydes is described. Conversion of 3 into the correspondi ng 2-(1-aryl-2-methoxycarbonylethyl)benzoic acids 4 by treatment with 1-met hoxy-1-trimethylosiloxyethene in the presence of titanium tetrachloride, as a way of regiospecific transformation of benzoic acids, is also described.