Synthesis of pyrimido[4,5-b]indoles and benzo[4,5]furo[2,3-d]pyrimidines via palladium-catalyzed intramolecular arylation

Various pyrimido[4,5-b]indoles and benzo[4,5]furo[2,3-d]pyrimidines were synthesized via a palladium-catalyzed intramolecular arylation of pyrimidine substrates. Thus, 4-aryloxy- or 4-anilino-5-iodopyrimidines were treated with Pd(OAc)2(PPh3)2 and base in DMF to give the regioselective cyclized heterocycles.