Chemicals from Alkynes with Palladium Catalysts

An overview of the use of alkynes as starting materials for the preparation of compounds, using procedures carried out under palladium catalysis, is studied. The transition metal-catalyzed conversion of internal and terminal alkynes to substituted benzene derivatives by a cyclotrimerization process is an old procedure that has been achieved using palladium species as catalysts. Benzynes have been generated and react with internal alkynes in the presence of an aryl iodide to give substituted phenanthrenes under Pd2(dba) 3 catalysis. Highly substituted indenes have been obtained by palladium-catalyzed carboannulation of internal alkynes using appropriately functionalized aryl halides. Despite all of these developments, plenty of work is still ahead to achieve low loadings of catalytic systems, supported or not, applicable to the reaction of alkynes.