A general synthetic route to 4‐substituted‐2,2′‐bithiophenes

A new synthetic route to 4‐substituted‐2,2′‐bithiophenes has been developed utilizing 4‐bromo‐2,2′‐bithiophene ( 1 ). Formation of the bithienyllithium adduct via halogen‐metal exchange was found to be problematic and resulted in complex mixtures of products. The Grignard reagent of 1 can be obtained easily via the “entrainment” method, allowing the production of 4‐substituted‐2,2′‐bithiophenes (where sub‐stituent = octyl, hydroxyethyl, hydroxymethyl, carboxy, carbomethoxy, acetoxyethyl, and acetoxymethyl).