Carbon-heteroatom bonds palladium© chloride

While the major use for palladium catalysis is to make carbon-carbon bonds, which are difficult to make using conventional reactions, the success of this approach has recently led to its application to forming carbon-heteroatom bonds as well. The Overall result is a nucleophilic substitution at a vinylic or aromatic centre, which would not normally be possible. A range of aromatic amines can be prepared direcdy from the corresponding bromides, iodides, or triflates and the required amine in the presence of palladium(O) and a strong alkoxide base. Similarly, lithium thiolates couple with vinylic triflates to give vinyl sulfides provided lithium chloride is present. 

Novel Palladium Chloride-Based Catalysts for Carbon-Carbon / Carbon-Heteroatom Bond Formations. The past decade has witnessed the development of novel palladacycles as a new class of catalysts for carbon-carbon/carbon-heteroatom bond-forming reactions. Several types of palladacycles (derived from PdCl2) have appeared in the literature. These include PC type, PCP pincer type, phosphite palladacycles, NC type, NCN pincer type, and sulfur containing palladacycles. Heterogeneous palladacycles have also been reported in the literature. These palladacycles are obtained via direct metallation from appropriate ligands with either PdCl2 or Na2PdCl4. Typical examples are shown in Scheme 1. 

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