Catalytic Synthesis of Saturated Oxygen Heterocycles by Hydrofunctionalization of Unactivated Olefins: Unprotected and Protected Strategies
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- 作者：Hiroki Shigehisa ; Miki Hayashi ; Haruna Ohkawa ; Tsuyoshi Suzuki ; Hiroki Okayasu ; Mayumi Mukai ; Ayaka Yamazaki ; Ryohei Kawai ; Harue Kikuchi ; Yui Satoh ; Akane Fukuyama ; Kou Hiroya
- 刊名：Journal of the American Chemical Society
- 出版年：2016
- 出版时间：August 24, 2016
- 年：2016
- 卷：138
- 期：33
- 页码：10597-10604
- 全文大小：673K
- 年卷期：0
- ISSN：1520-5126
文摘
A mild, general, and functional group tolerant intramolecular hydroalkoxylation and hydroacyloxylation of unactivated olefins using a Co(salen) complex, an N-fluoropyridinium salt, and a disiloxane reagent is described. This reaction was carried out at room temperature and afforded five- and six-membered oxygen heterocyclic compounds, such as cyclic ethers and lactones. The Co complex was optimized for previously rare medium ring formation by hydrofunctionalization of unactivated olefins. The powerful Co catalyst system also enables the deprotective hydroalkoxylation of O-protected alkenyl alcohol and hydroacyloxylation of alkenyl ester to afford cyclic ethers and lactones directly. The substrate scope and mechanistic proof of deprotection were investigated. The experimental evidence supports the concerted transition state of the bond-forming step involving a cationic Co complex.