Nickel-phosphine complex-catalyzed Grignard coupling—II

A general, versatile method for alkylation and arylation of haloheterocyclic compounds is reported. In the presence of a catalytic quantity of [NiCl2(dppp)], where dppp stands for Ph2P(CH2)3PPh2, bromothiophenes, halopyridines, haloquinoline, and haloisoquinolines reacted with alkyl and aryl Grignard reagents at room temperature or at ether refluxing temperature to give the cross-coupling products. The coupling reaction has been applied to the synthesis of isoquinoline alkaloids. Reactivities of 2-thienyl and 2-pyridyl Grignard reagents have also been examined.