Palladium(II)-Catalyzed Synthesis of 2H,3鈥?i>H-Spiro[benzofuran-3,2鈥?naphthoquinones]

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• 作者：Pieter Claes ; Jan Jacobs ; Bart Kesteleyn ; Tuyen Nguyen Van ; Norbert De Kimpe
• 刊名：Journal of Organic Chemistry
• 出版年：2013
• 出版时间：September 6, 2013
• 年：2013
• 卷：78
• 期：17
• 页码：8330-8339
• 全文大小：435K
• 年卷期：v.78,no.17(September 6, 2013)
• ISSN：1520-6904

文摘

2H,3鈥?i>H-Spiro[benzofuran-3,2鈥?naphthoquinones], constituting a new spiroheterocyclic skeleton, were synthesized starting from 2-aryloxymethyl-1,4-naphthoquinones by means of a palladium(II)-catalyzed reaction, which is a new spirocyclic transformation. Under optimal conditions, i.e. 10 mol % of palladium(II) acetate, 15 mol % of 3,5-dichloropyridine, and 5 mol % of trifluoroacetic acid in acetic acid at 110 掳C, various 2H,3鈥?i>H-spiro[benzofuran-3,2鈥?naphthoquinones] were synthesized in yields strongly dependent on the substitution pattern of the aryloxy group. Unsubstituted or ortho-substituted 2-aryloxymethyl-1,4-quinones were found to rearrange toward the corresponding 2-(4-hydroxyaryl)-1,4-quinones upon treatment with trifluoroacetic acid.