Furo[3,2-c]coumarin 為自然界中常見的雜環化合物之一。因其豐富的藥理活性而被人們作為藥物使用。利用實驗室在 2010 年發表的文獻中，合成四取代呋喃時單離出兩性離子中間體為契機，我們開發出簡單且直接的方法去合成 furo[3,2-c]coumarin。反應使用4-羥基香豆素 13 作為起始物，先與醛試劑 50 進行羥醛縮和反應。隨後反應中的磷試劑進行共軛加成，單離出兩性離子化合物 48，產率介於 50-98%。再將化合物 48、醯氯試劑 51 與三乙胺加入反應中，先由兩性離子 48 進行氧-醯化反應後，由三乙胺去質子化再進行分子內 Wittig 反應。我們即可得到呋喃香豆素 49，產率介於 61-99%。

　　Furo[3,2-c]coumarin is one kind of the heterocyclic compounds abundant in nature. It has attracted scientists much attention because of its broad pharmacological activities. In 2010, our research reported a general preparation of tetrasubstituted furans via phosphorus zwitterions as key intermediates. Based on these observation, we want to develop a new synthetic protocol for the preparation of furo[3,2-c]coumarins using the corresponding stable phosphorus zwitterions. These new, stable phosphorus zwitterions can be prepared by our developed methodology starting from 4-hydroxy coumarin 13, the corresponding aldehydes 50, and tributylphosphine. All of the new type of phosphine zwitterions 48 can be generated in good yield (50-98%). The compounds 48 can be further acylated by the corresponding acid chlorides 51 and then deprotonated by triethylamine, and finally undergo intramolecular Wittig reactions to provide the corresponding highly functional furo[3,2-c]coumarins in good to high yield (61-99%).

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