Selective direct arylation of 3-bromo-2-methylthiophene: a building-block for electro- and photoactive organic materials

Selective direct arylation of 3-bromo-2-methylthiophene with aryl bromides to form a library of 2-aryl-4-bromo-5-methylthiophenes is demonstrated. The reaction yields varied from 27–63%. The inherent selectivity observed is attributed to the lack of oxidative insertion of the bromine in 3-bromo-2-methylthiophene. This method will be useful for the facile preparation of functional organic electronic materials.