Regio- and Stereoselective Monoepoxidation of Dienes using Methyltrioxorhenium: Synthesis of Allylic Epoxides

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• 作者：Saroj Ranjan De ; Ganesh Kumar ; Jawahar L. Jat ; Saritha Birudaraju ; Biao Lu ; Rajkumar Manne ; Narender Puli ; Adeniyi Michael Adebesin ; John R. Falck
• 刊名：Journal of Organic Chemistry
• 出版年：2014
• 出版时间：November 7, 2014
• 年：2014
• 卷：79
• 期：21
• 页码：10323-10333
• 全文大小：599K
• ISSN：1520-6904

文摘

Methyltrioxorhenium (MTO) complexed with pyridine was shown to be a highly effective catalyst for the regioselective monoepoxidation of conjugated di- and trienes using 30% H₂O₂ at or below room temperature. The resultant allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well as substructures present in many bioactive natural products. The site of epoxidation was dependent upon olefin substitution, olefin geometry (Z vs E), and the presence of electron-withdrawing substituents on adjacent carbons. For 1-acyl(silyl)oxypenta-2,4-dienes, epoxidation of the distal olefin was generally favored in contrast to the adjacent regioselectivity characteristic of Sharpless, peracid, and other directed epoxidations of hydroxylated dienes.