Iodine-Promoted Efficient Homocoupling of Arylboronic Acids in PEG-400 under Aerobic Conditions

Iodine is able to catalyze the homocoupling of arylboronic acids in moderate to good yields in PEG-400 under aerobic conditions. This transition-metal-free catalytic system is readily available at low cost, which is practical and useful. It is noteworthy that a high activity of our catalytic system could be maintained under mild conditions (100 degrees C) by addition of water. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)