Polystyrene-supported diaminocarbene complexes of palladium(II): synthesis, characterization and application as a precatalyst in Sonogashira–Hagihara and Suzuki–Miyaura cross coupling

One of the topical research areas dealing with Pd-catalyzed cross-coupling reactions is the development of regenerable catalytic systems through immobilization of highly active palladium complexes, clusters or nanoparticles onto an inert support. In the context of increased environmental requirements, highly active and multiply reusable heterogeneous catalytic systems have a number of practical advantages over homogeneous analogues. In this review, various approaches to immobilization on a polystyrene support of N-heterocyclic carbene and acyclic diaminocarbene palladium complexes have been considered for the first time; these complexes are a promising alternative to the widely used phosphine complexes. Special attention focuses on modern physicochemical methods used for investigation of corresponding heterogeneous systems. In addition, examples are given of using reusable heterogeneous catalysts for Sonogashira–Hagihara and Suzuki–Miyaura reactions, with emphasis on the true nature of the palladium catalytic species.
The bibliography includes 83 references.