Claisen-Schmidt condensation of 4-(tetrahydropyran-2-yloxy)acetophenone with 2-methoxy-4-[(3-methylbut-2-en-1-yl)oxy]benzaldehyde gave a THP-protected chalcone ether. Removal of the THP group under mild acidic conditions gave the corresponding chalcone ether, which underwent a water-accelerated Claisen rearrangement under microwave irradiation or heating in a sealed tube in aqueous ethanol to give a good yield of licochalcone A, which has diverse biological activities; no product of deprenylation or abnormal Claisen rearrangement was formed. The abnormal Claisen rearrangement of γ-substituted allyl aryl ethers is known to be a problem in [3,3]-sigmatropic rearrangement reaction; this, however, was not detected in our water-accelerated system.

rearrangements - condensation - natural products - licochalcone A

4-（四氢吡喃-2-基氧基）苯乙酮与2-甲氧基-4-[（3-甲基丁-2-烯-1-基）氧基]苯甲醛的克莱森-施密特缩合反应得到THP保护的查耳酮醚。在温和的酸性条件下除去THP基团，得到相应的查耳酮醚，将其在微波辐射下或在密闭管中于乙醇水溶液中加热，进行水加速的克莱森重排，以提供具有良好生物活性的良好的苯并och酮A。没有形成去戊烯基化或克莱森异常重排的产物。已知γ-取代的烯丙基芳基醚的异常克莱森重排是[3,3]-σ重排反应中的一个问题。但是，在我们的水加速系统中未检测到此问题。

重排-缩合-天然产物-licochalcone A