A convenient and practical approach to coumestans has been successfully developed by using a one‐pot tandem demethylation/annulation/oxidation reaction sequence that employs easily accessible 2,3‐bis(2‐methoxyphenyl)‐3‐oxopropanals as the starting material. This synthetic protocol provided a variety of coumestan derivatives in good to excellent yields under mild conditions. The exploration of biologically active coumestan compounds is a potential application of this synthetic method.

A one‐pot tandem demethylation/annulation/oxidation sequence that employs 2,3‐bis(2‐methoxyphenyl)‐3‐oxopropanals as the starting material provides a variety of coumestan derivatives in good to excellent yields under mild conditions.