Synthesis of 4-substituted and 3,4-disubstituted indazole derivatives by palladium-mediated cross-coupling reactions

The synthesis of 4-substituted indazole derivatives by palladium-mediated cross-coupling reactions was described. Suzuki, Heck, Sonogashira and Stille cross-coupling reactions were used to introduce aryl, vinyl and alkynyl substituents in 4-position of indazole derivatives. The selectivity of bis-Suzuki reactions of 3,4-diiodo- and 3-bromo-4-iodoindazoles was investigated.