Highly efficient and facile alkylation of 4H-cyclopenta-[2,1-b:3,4-b′]dithiophene in water

Abstract

A new and highly convenient method to perform alkylation of 4H-cyclopenta-[2,1-b:3,4-b′]dithiophene (CPDT) in aqueous conditions is reported. This method was also extended to successfully perform alkylation of 2,6-dibromo-4H-cyclopenta-[2,1-b:3,4-b′]dithiophene for the first time. This facile method has several advantages such as the exclusive use of water instead of high boiling toxic solvents, simple separation of the defect free dialkylated CPDT product and the use of mild reaction conditions. Despite using mild reagents and reaction conditions, to our delight, very high yields of up to 98% pure dialkylated CPDT products are obtained much more readily by this method in less time than literature procedures. The isolated products were identified by HRMS and solution NMR measurements to be solely the desired dialkylated product with the alkyl halides used here.