Ullmann Diaryl Etherification Using an Immobilized Copper(II) Catalyst

Significance

3-(2-Aminoethylamino)propyl-functionalized silica gel immobilized copper(II) catalyst 1 was prepared via the two-step procedure shown in eq. 1. The reaction of phenols with aryl iodides, aryl bromides and aryl chlorides in the presence of potassium fluoride as a base in DMSO at 130 °C gave the corresponding cross-coupling products 2 in 73-99% yields by use of catalyst 1 (eq. 2). The silica gel supported catalyst 1 was readily recovered from the reaction mixture by simple filtration and reused 10 times without decrease in activity.