Clean and Efficient Iodination of Thiophene Derivatives

Iodination of thiophene derivatives is realized using a simple, fast, and efficient methodology. Iodination of thiophene and 2- or 3-substituted or 3,4-disubstituted thiophenes with N-iodosuccinimide (NIS) activated with 4-toluenesulfonic acid in ethanol gives pure iodinated products that require no further purification.