The following reaction was performed under inert gas atmosphere. 3,5-dibromo-2-methylthiophene (B) (9.7 g, 37.9 mmol, 1 eq) was dissolved in anhydrous THF in a two-necked round bottom flask. The mixture was cooled to -78 °C. To the stirred solution 2.5 M n-BuLi (16 ml, 39.8 mmol, 1.5 eq) was added dropwise. The reaction was stirred for 15 minutes at -78 °C and then tributyl borate (10.46 g, 45.5 mmol, 1.2 eq) was slowly added to the mixture followed by slow warm up to RT and further stirring at RT for 24h. The reaction mixture was quenched with 110 ml of 1M HCl and stirred for additional 1 h. Then THF was removed under vacuum and the mixture was extracted with Et2O (3 × 50 ml). The organic layers were combined and the boronic acid was removed by washing with 2M NaOH solution (3 × 50 ml). The combined aqueous layers were carefully acidified to neutral using conc. HCl. The obtained off-white-toyellow solid was filtered and dried under vacuum (yield: 5.