Copper(I)/Ligand-Catalyzed 5-endo Radical Cyclization–Aromatization of 2,2,2-Trichloroethyl Vinyl Ethers: Synthesis of 2,3-Difunctionalized 4-Chlorofurans

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• 作者：Ram N. Ram ; Dharmendra Kumar Gupta ; Vineet Kumar Soni
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：February 19, 2016
• 年：2016
• 卷：81
• 期：4
• 页码：1665-1674
• 全文大小：632K
• ISSN：1520-6904

文摘

Copper(I)/ligand-catalyzed one pot synthesis of highly substituted 2,3-difunctionalized-4-chlorofurans has been reported. The reaction proceeds via a Cu(I)-catalyzed regioselective 5-endo-trig radical cyclization of 2,2,2-trichloroethyl vinyl ethers followed by the base-promoted dehydrochlorination. The success of the kinetically disfavored 5-endo cyclization was attributed to the formation of captodatively stabilized radical intermediate in the cyclization step and relatively high reaction temperature. Synthetic application of this protocol was also demonstrated in the preparation of alkyl and aryl substituted 4-chlorofuranonapthoquinones.