Preparation of 2-arylated-1,4-phenylenediamines by palladium-catalyzed cross-coupling reactions

Protected 2-iodo-1,4-phenylenediamines were converted to the corresponding magnesium derivative by performing an iodine–magnesium exchange. After transmetalation with zinc bromide, a palladium(0)-catalyzed cross-coupling with various aryl iodides and 5-bromo-2-carbethoxyfuran furnished the expected cross-coupling products in 52–79% yield.