Decarboxylative Iodination of Coumarin-3-carboxylic Acids: A Facile Access to 3-Iodocoumarins

Abstract

A straightforward protocol for the direct conversion of readily available coumarin-3-carboxylic acids to the corresponding 3-iodocoumarins is described herein. Heating acetonitrile solution of coumarin-3-carboxylic acids, molecular iodine and potassium hydrogen phosphate resulted in the decarboxylative iodination of coumarin-3-carboxylic acids via radical mechanism. Various electron rich and electron poor coumarin-3-carboxylic acids were compatible with the established reaction conditions and consequently afforded the corresponding 3-iodocoumarins in (46-93 %) reaction yields with minimum purification efforts. The formed products serve as valuable precursors to streamline more complex organic compounds incorporating coumarin core.