I did the halogen dance reaction of 2-bromo-5-TIPS thiophene using LDA/methanol to get 3-bromo-5-TIPS thiophene. But there reaction was not completed 100% and there is ~5-10% of starting material as checked from 1H-NMR. Both compound have almost same boiling point and same Rf value in TLC. I am looking some way to get pure final product. Thanks