Kumada coupling reaction, microwave

Low reactive aryl chlorides are converted to the respective organomagnesium species in excellent yields through transition metal catalysis using 2 mol% FeCU (4-6, equation 3). Alternatively, a safe and reproducible method for activation of aryl chlorides or bromides 7 uses microwave irradiation (equation 4). In a synthesis of a novel HIV-1 protease inhibitor, microwave irradiation was essential to generate the starting arylmagnesium halide as well as to promote the subsequent Kumada coupling reaction. ... 

Microwaves were utilized both in the preparation of the Grignard reagent and in the Kumada couplings [161] with aryl chlorides. It was noted in this case that a higher amount of homocoupling side-products was typically formed when microwaves were used as a heating source than when the reaction was carried out by employing ultrasound at ambient temperature (Scheme 74) [156]. 

Walla, P., Kappe, C. O. Microwave-assisted Negishi and Kumada cross-coupling reactions of aryl chlorides. Chem. Common. 2004, 564-565. 

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