Abstract

Friedel–Crafts alkylation of indole and its derivatives with a variety of electron-deficient alkenes catalyzed by Mg and Ca salts has been studied. The dependence of the results on the nature of the starting olefins, substituents on indole, and Michael acceptors, as well as on the composition of the Lewis acid is discussed. High yields of the addition products were achieved in the addition of indole to β,γ-unsaturated α-keto esters and coumarin derivatives, some nitroolefins, and arylidenemalonates. Reactions involving arylidenemalonates were found to be the most versatile and smooth, the best yields reached 92%. Among the Mg and Ca salts tested, magnesium iodide (MgI₂) proved to be the most appropriate catalyst in the addition to various unsaturated carbonyl compounds, while calcium triflimide [Ca(NTf₂)₂] efficiently catalyzed the addition to nitroolefins.

Friedel–Crafts alkylation of indole and its derivatives with a variety of electron-deficient alkenes catalyzed by Mg and Ca salts has been studied. The dependence of the results on the nature of the starting olefins, substituents on indole, and Michael acceptors, as well as on the composition of the Lewis acid is discussed. High yields of the addition products were achieved in the addition of indole to β,γ-unsaturated α-keto esters and coumarin derivatives, some nitroolefins, and arylidenemalonates. Reactions involving arylidenemalonates were found to be the most versatile and smooth, the best yields reached 92%. Among the Mg and Ca salts tested, magnesium iodide (MgI₂) proved to be the most appropriate catalyst in the addition to various unsaturated carbonyl compounds, while calcium triflimide [Ca(NTf₂)₂] efficiently catalyzed the addition to nitroolefins.

中文翻译：

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镁和钙盐催化的吲哚与迈克尔受体的弗里德-克拉夫特反应

摘要

已经研究了Mg和Ca盐催化的吲哚及其衍生物与多种电子缺陷的烯烃的Friedel-Crafts烷基化反应。讨论了结果对起始烯烃的性质，吲哚和迈克尔受体上的取代基以及路易斯酸的组成的依赖性。将吲哚添加到β，γ-不饱和α-酮酸酯和香豆素衍生物，一些硝基烯烃和芳基丙二酸酯中可实现高收率的加成产物。发现涉及芳基丙二酸酯的反应是最通用和最平滑的，最高收率达到92％。在所测试的Mg和Ca盐中，除了各种不饱和羰基化合物外，碘化镁（MgI ₂）被证明是最合适的催化剂，而三氟甲磺酸钙[Ca（NTf₂）₂ ]有效地催化了向硝基烯烃的加成。

已经研究了Mg和Ca盐催化的吲哚及其衍生物与多种电子缺陷的烯烃的Friedel-Crafts烷基化反应。讨论了结果对起始烯烃的性质，吲哚和迈克尔受体上的取代基以及路易斯酸的组成的依赖性。将吲哚添加到β，γ-不饱和α-酮酸酯和香豆素衍生物，一些硝基烯烃和芳基丙二酸酯中可实现高收率的加成产物。发现涉及芳基丙二酸酯的反应是最通用和最平滑的，最高收率达到92％。在所测试的Mg和Ca盐中，除了各种不饱和羰基化合物外，碘化镁（MgI ₂）被证明是最合适的催化剂，而三氟甲磺酸钙[Ca（NTf₂）₂ ]有效地催化了向硝基烯烃的加成。