Carbonyl Directed Regioselective Hydration of Alkynes under Ag-Catalysis

A mild strategy for highly regioselective hydration of the alkynes (internal and terminal) has been developed employing intramolecular ketone as the directing group under Ag(I) catalysis. In this process both internal and terminal alkynes exhibited 100 % complementary reactivity i. e. 6-endo-dig vs. 5-exo-dig respectively, and provided two regio-isomeric dicarbonyl products as exclusive products. This process found very broad scope for the ketones and alkynes. The 1,5-diketones were efficiently transformed in to synthetically and pharmaceutically important naphthalene derivatives employing an intramolecular Aldol condensation.