Brønsted Base‐Catalyzed Tandem Cyclization of 2‐Nitrochalcones With Biomass‐Derived Alcohols for Synthesis of 3‐Alkoxyindoles

ABSTRACT An unprecedented tandem cyclization reaction for synthesizing 3‐alkoxyindoles in one pot was described, utilizing 2‐nitrochalcone derivatives and various biomass‐derived alcohols under Brønsted base catalysis in a corresponding alcohol solvent system. The method is highly atom‐economical and efficient, and structurally diverse 3‐alkoxyindoles were prepared in good yields (76%–88%) in only 30 min. In addition, the system has excellent atom economy and green synthesis characteristics, minimizes the generation of by‐products, and achieves high‐value conversion and sustainable utilization of biomass‐derived alcohols. This new method enables the base‐catalyzed dehydrogenation of alcohols and the synergistic activity of nitro and α, β ‐unsaturated ketone structures, and the synergistic activation of multiple bonds under mild conditions.