Synthesis of Oxygen-containing Heterocycles Using Palladium(II) Catalysts

Alkenes, dienes, and alkynes hearing hydroxy groups, when treated with palladium(I1) catalysts, afford a variety of oxygen-containing heterocycles via cyclizations involving intramolecular oxypalladation as a key step.Trapping the oxypalladation intermediates with CO also creates useful entries to oxygen-containing heterocycles.Synthetic aspects of these cyclizations as well as the catalyses of palladium(I1) are surveyed in this article.A novel strategy for synthesizing heterocycles under mild conditions is provided by the use of metal complex catalysts.Among those, palladium complexes undoubtedly lie in a unique position in terms of its versatility and reactivity.'