Cihaner and Onal reported the synthesis of 3-bromo-4-methoxythiophene in 70% yield by the reaction of methanolate anion on 3,4-dibromothiophene in the presence of CuO and KI. 12 However, this protocol suffers from various drawbacks. Firstly 3,4-dibromothiophene is an expensive starting material, which is synthesized in two steps from thiophene. 13 and 14 Secondly the procedure requires a long reaction time of about 3 days. We recently reported that the reaction time ...
