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有机化学 ›› 2012, Vol. 32 ›› Issue (12): 2334-2338.DOI: 10.6023/cjoc201207030 上一篇    下一篇

研究简报

2,3-二氯-5,6-二氰基苯醌/H+作用下4-苯亚甲基-3-异色酮的分子内氧化偶联反应

戢得蓉a, 粟立丹a, 张成刚a,b   

  1. a 四川师范大学化学与材料科学学院 成都 610066;
    b 先进功能材料四川省高校重点实验室 成都 610066
  • 收稿日期:2012-07-20 修回日期:2012-08-28 发布日期:2012-09-03
  • 通讯作者: 张成刚 E-mail:zhangcg2008@yahoo.com.cn
  • 基金资助:

    四川省教育厅(No. 12ZA141)及先进功能材料四川省高校重点实验室(No. KFKT2013-01)资助项目.

Intramolecular Oxidative Coupling Reaction of 4-Phenylmethyl-ene-3-isochromanones with 2,3-Dichloro-5,6-dicyanobenzo- quinone as an Oxidant

Ji Deronga, Su Lidana, Zhang Chengganga,b   

  1. a College of Chemistry and Mateials, Sichuan Normal University, Chengdu 610066;
    b Key Laboratory of Advanced Functional Materials, Sichuan Province Higher Education System, Chengdu 610066
  • Received:2012-07-20 Revised:2012-08-28 Published:2012-09-03
  • Supported by:

    Project supported by the Department of Education of Sichuan Province (No. 12ZA141) and the Key Laboratory of Advanced Functional Materials of Sichuan Province Higher Education System (No. KFKT2013-01).

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多甲氧基菲-9-甲酸及酯是合成娃儿藤生物碱及其类似物的关键中间体. 以4-(3,4-二甲氧基苯亚甲基)-6,7-二甲氧基-3-异色酮(6)为底物, 2,3-二氯-5,6-二氰基苯醌(DDQ)/CH3SO3H作为氧化体系, 没有得到预期的多甲氧基菲-9-甲酸内酯(1), 意外产物经核磁共振等确定为两个新的3-取代苯基香豆素2, 3. 进一步的实验研究显示: 底物发生分子内脱氢偶联为香豆素2而非菲环化合物1, 是因为异色酮6苯环A上2位取代基的存在所致, 其内酯环开环化合物10以及2,3-二苯基丙烯酸(12)的对比实验印证了该取代基对脱氢偶联反应选择性的影响; 异色酮6氧化偶联为香豆素2的反应机理可能为酸解开环以及途经自由基正离子的脱氢偶联, 香豆素3为DDQ氧化2的前体化合物8所得.

关键词: 多甲氧基菲, 3-异色酮, 3-苯基香豆素, 脱氢偶联, 自由基正离子, 分子内氧化偶联, DDQ

Polymethoxy-substituted phenanthrene-9-carboxylic acid or methylate is key intermediate for synthesis of tylophora alkaloids. (E)-4-(3,4-Dimethoxybenzylidene)-6,7-dimethoxy-1H-isochromen-3(4H)-one (6), oxided by 2,3-dichloro- 5,6-dicyanobenzoquinone (DDQ)/CH3SO3H in CH2Cl2, gave no polymethoxy-substituted phenanthrene derivative (1) but unexpected 3-(2-(hydroxymethyl)-4,5-dimethoxyphenyl)-6,7-dimethoxy-2H-chromen-2-one (2) and 4,5-dimethoxy-2-(6,7-dimethoxy-2-oxo-2H-chromen-3-yl)benzaldehyde (3). Further experiments showed that the steric hindrance of a ring of isochromen-3-one (6) resulted in coumarin (2) not phenanthrene derivative (1), supported by comparative experiments of 2,3-diphenylacrylic acid (10, 12). The possible mechanism of 2 via radical cation and 3 through oxidation of precursor of 2 was proposed based on the result of experiments.

Key words: polymethoxylphenanthrene, 3-isochromanone, 3-phenylcoumarin, cross dehydrogenative coupling (CDC), radical cation, intramolecular oxidative coupling, DDQ