Synthesis of o-diorganylphosphino-substituted benzoic acids and their derivatives

o-Substituted dialkyl- and alkylphenylphosphinobenzoic acids, as well as their esters, nitriles, and amides, including those containing three different substituents on the phosphorus atom, were prepared for the first time by two different synthetic procedures. The most general procedure involves metal-halogen exchange in bromo- and iodoarenes, followed by phosphorylation of the resulting lithium derivatives.