Renewable Thiophene Synthesis from Biomass Derived Methyl Levulinate and Elemental Sulfur

Heterocyclic compounds are pivotal building blocks in petrochemical and renewable fine chemical synthesis. The production of bio‐based heterocyclic compounds is limited to furans and pyrroles, while thiophenes are rarely prepared from bio‐based feedstock in a real renewable method. Current research on the “pseudo‐renewable” thiophene synthesis strongly relies on unwieldy Lawesson's Reagent, which makes the process unsustainable. The present work describes for the first time that, two thiophene diesters were synthesized from biomass‐derived methyl levulinate and elemental sulfur, a cheap, surplus by‐product of the fossil industry that is causing potential pollution. The condensation and sulfurization steps in this process all involved multiple reaction pathways, leading to a much more intricate mechanism than previous research in its type. The footprint of sulfur in this system was tracked throughout the process, and the chemistry of this multi‐step reaction provided a new orientation for the real sustainable thiophene synthesis based on elemental sulfur.