摘要/Abstract

发展了一种有机催化的邻羟基苯基取代对甲亚基苯醌和β-氧代酰基吡唑之间的不对称[4+2]环化反应, 为光学活性3,4-二氢香豆素衍生物的获取提供了有效途径. 在衍生自奎宁的手性双功能方酰胺催化下, 一系列邻羟基苯基取代对甲亚基苯醌和β-氧代酰基吡唑可以在温和的条件下顺利地发生反应, 以高产率和优秀的非对映及对映选择性得到相应的多取代3,4-二氢香豆素衍生物.
关键词: 不对称合成, 3,4-二氢香豆素, 邻羟基苯基取代对甲亚基苯醌, β-氧代酰基吡唑, 有机催化
An organocatalyzed asymmetric formal [4+2] annulation of ortho-hydroxyl functionalized p-quinone methides with β-keto acylpyrazoles has been developed, which provides an efficient approach to access optically active 3,4-dihydro- coumarins. Under the catalysis of a quinine-derived bifunctional squramide, the reactions of a wide range of ortho-hydroxy- phenyl substituted p-quinone methides and β-keto acylpyrazoles took place smoothly to generate the corresponding polysubstituted 3,4-dihydrocoumarins in good yields with high levels of diastereo- and enantio-selectivities (up to 96% yield, >19/1 dr and 98% ee) under mild reaction conditions.
Key words: asymmetric synthesis, 3,4-dihydrocoumarin, ortho-hydroxyphenyl-substituted para-quinone methide, β-keto acylpyrazole, organocatalysis


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