Facile synthesis of dihydrochalcones via the AlCl3-promoted tandem Friedel–Crafts acylation and alkylation of arenes with 2-alkenoyl chlorides

Abstract Tandem Friedel–Crafts acylation and alkylation of arenes with 2-alkenoyl chlorides were investigated under the catalysis of Lewis acids. The cascade reaction affords dihydrochalcones in good yields accompanying 1-indanone derivatives in some cases, in the presence of anhydrous aluminum chloride. The scope, limitation, and mechanism of the tandem reaction were also explored. The intermolecular Friedel–Crafts alkylation for the formation of dihydrochalcones is more favorable than the intramolecular one for the generation of 1-indanones in the tandem reaction due to a stable six-membered ring transition state. The sequent process was further studied by the DFT computations at the M06-2X/6-31G(d) level, which are in great agreement with the experimental observation and support the proposed mechanism. The current method provides a convenient and economic method to synthesis of dihydrochalcones.