Synthesis of Furo[3,2-c]benzopyrans via an Intramolecular [4 + 2] Cycloaddition Reaction of o-Quinonemethides
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- 作者：Li-Ming Zhao ; Ai-Li Zhang ; Hua-Shuai Gao ; Jie-Huan Zhang
- 刊名：Journal of Organic Chemistry
- 出版年：2015
- 出版时间：October 16, 2015
- 年：2015
- 卷：80
- 期：20
- 页码：10353-10358
- 全文大小：309K
- ISSN：1520-6904
文摘
An intramolecular [4 + 2] cycloaddition reaction of o-quinonemethides generated from salicylaldehydes and 伪-prenylated alcohols is described. In the presence of a catalytic amount of benzenesulfonic acid (BSA), the reaction proceeded smoothly in EtOH to afford furo[3,2-c]benzopyrans through a three-bond forming process in moderate to excellent yields with high diastereoselectivity. This reaction provides a simple and straightforward protocol to efficiently construct furo[3,2-c]benzopyran skeletons. A possible mechanism involving hemiacetal formation/hetero-Diels鈥揂lder reaction is proposed to rationalize the observed results.