Methanesulfonic Acid‐Catalyzed Friedel‐Crafts Alkylation: Towards Sustainable Synthesis of Arylalkanes from Donor–Acceptor Cyclopropane Ketones

We present herein Brønsted acid‐catalyzed Friedel‐Crafts alkylation of phenols with Donor–Acceptor cyclopropane ketones. The presence of the 1,4‐diphenyl butan‐1‐one and 1,3‐diphenyl propane‐1‐one motifs in various naturally occurring biologically significant molecules inspired us to pursue the direct synthesis of these structural frameworks. Utilizing methanesulfonic acid (MeSO₃H) as a catalyst, we achieved a more environmentally friendly and high‐yielding synthesis, owing to its cost‐effectiveness, biodegradability, transition–metal and additives free conditions. Furthermore, we have successfully extended our developed methodology to thiophenols, resulting in the production of sulfur–based butan‐1‐one derivatives in good yields.