Ruthenium-Catalyzed C鈥揌 Activation/Cyclization for the Synthesis of Phosphaisocoumarins

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• 作者：Youngchul Park ; Incheol Jeon ; Seohyun Shin ; Jiae Min ; Phil Ho Lee
• 刊名：Journal of Organic Chemistry
• 出版年：2013
• 出版时间：October 18, 2013
• 年：2013
• 卷：78
• 期：20
• 页码：10209-10220
• 全文大小：565K
• 年卷期：v.78,no.20(October 18, 2013)
• ISSN：1520-6904

文摘

An efficient and cost-effective ruthenium-catalyzed oxidative cyclization of phosphonic acid monoesters or phosphinic acids with alkynes has been developed for the synthesis of a wide range of phosphaisocoumarins in good to excellent yields under aerobic conditions. A multitude of arylphosphonic acid monoesters and arylphosphinic acids having electron-donating and -withdrawing groups were oxidatively cyclized. Various diarylacetylenes, dialkylacetylenes, and alkylarylacetylenes effectively underwent the ruthenium-catalyzed oxidative cyclization. A substrate possessing benzoic acid as well as a phenylphosphonic monoester moiety was smoothly cyclized with hex-3-yne to afford a compound having both isocoumarin and phosphaisocoumarin moieties. Alkenylphosphonic monoester afforded phosphorus 2-pyrone through oxidative cyclization with alkyne. Competition experiments between diaryl- and dialkylalkynes and between diarylacetylenes having p-methoxy and p-chloro groups gave results which showed that the present oxidative cyclizations were not affected by the electronic effects of alkynes. Mechanistic studies revealed C鈥揌 bond metalation to be the rate-limiting step.