Cross coupling reaction between aryl:boronic acid and aryl halide - in presence of catalyst and large excess of base to minimise coupling between boronic acid molecules

摘要

Cross-coupling reaction between arylboronic acid and aryl halide in a 2-phase solvent system in presence of transition metal catalyst and base is improved when at least 3 moles base are used per mole boronic acid. ADVANTAGE - All steps are done at a temp. permitting safe and simple operation, to economical, large-scale prodn. of (I) is possible. The formation of homo-coupled products from (II) is almost completely prevented.