Volhard–Erdmann cyclization
The Volhard–Erdmann cyclization is an organic synthesis of alkyl and aryl thiophenes by cyclization of disodium succinate or other 1,4-difunctional compounds with phosphorus heptasulfide. The reaction is named after Jacob Volhard and Hugo Erdmann.
An example is the synthesis of 3-methylthiophene starting from itaconic acid:
