Salicylic acids and substituted ynones were employed as substrates to afford a class of valuable 4H-benzo[d][1,3]dioxin-4-ones with a 2-site quaternary carbon structure in up to 92% yield by secondary amine-catalyzed dual Michael cascade reactions under mild reaction conditions. The α,β-unsaturated ketone as the key intermediate in the cascade process was successfully separated and characterized. As a result, a new reaction route for ynone species is demonstrated, which is totally different from the existing allenamine activation model.

中文翻译：

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通过仲胺催化的双Michael级联反应高效合成具有2位季碳结构的苯并二恶英†

水杨酸和取代的炔酮被用作底物，以提供一类有价值的4 H-苯并[ d ] [1,3]二恶英-4-酮，其具有2位季碳结构，仲胺-收率最高可达92％。在温和的反应条件下催化双重Michael级联反应。成功地分离和表征了α，β-不饱和酮作为级联过程中的关键中间体。结果，证明了一种用于炔酮的新反应路线，这与现有的艾伦胺活化模型完全不同。