Protecting-group-free synthesis of carboxylic group substituted alkynes by Sonogashira coupling in neat water

Abstract

An effective, economic and green synthesis of carboxylic group substituted alkynes by Sonogashira coupling of halogenated aromatic acids with phenylacetylene has been developed. The coupling reaction proceeds well using Pd(OAc)(2)/TPPTS-CuI as catalyst with K(2)CO(3) as base in water. It is worth noting that this procedure avoids the protection/deprotection steps of carboxylic group and obtains the title compounds in good to excellent yields.