Intramolecular Cyclization Reactions of 5-Halo- and 5-Nitro-Substituted Furans

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• 作者：Kenneth R. Crawford ; Scott K. Bur ; Christopher S. Straub ; and Albert Padwa
• 刊名：Organic Letters
• 出版年：2003
• 出版时间：September 4, 2003
• 年：2003
• 卷：5
• 期：18
• 页码：3337 - 3340
• 全文大小：79K
• 年卷期：v.5,no.18(September 4, 2003)
• ISSN：1523-7052

文摘

Intramolecular cyclization reactions of 5-halo- and 5-nitro-substituted furanylamides were examined. The 2-alkoxy-5-bromofuran derivative 2produced the rearranged dihydroquinone 6 (36%), a product from the rearrangement of the intermediate oxabicycle 3. The 5-halo substitutedfuroyl amide 18 was converted to the polyfunctional oxabicycle 20 in 82% yield and at a much faster rate than the unsubstituted furanylsystem 17. The 5-nitro-substituted furfuryl amide 33b underwent an unusual isomerization-cyclization reaction under microwave conditionsto provide 1,4-dihydro-2H-benzo[4,5]furo[2,3-c]pyridin-3-one 34.

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