An ‘on‐water’ protocol has been developed for the synthesis of combretastatin A‐4 (CA‐4) analogues by cyclization of polarized triaryldivinyl ketones using hydrochloric acid as a promoter in 45–95% yields. The reaction time was reduced by about 30 times due to ultrasonic irradiation at ambient temperature. The other advantages of this new method are operational simplicity, easy workup, no column purification, and applicability on a gram‐scale. It was shown that the amphiphilicity of the substrate and a low energy barrier of the reaction are a prerequisite for electrophilic and concerted reactions under aqueous and ambient conditions.

中文翻译：

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偏二乙烯基酮在水和环境条件下的环化

已经开发了一种“水上”方案，用于通过使用盐酸作为促进剂，使极化的三芳基二乙烯基酮环化，以45-95％的产率合成康维他汀A-4（CA-4）类似物。由于在环境温度下进行超声波照射，反应时间减少了约30倍。这种新方法的其他优点是操作简便，易于操作，无需色谱柱纯化以及适用于克级。结果表明，在水和环境条件下，底物的两亲性和反应的低能垒是亲电和协同反应的先决条件。