Alcohols react with arenes in the presence of cationic iron(III) porphyrin catalyst. The reaction involves the formation of the C–C bond via dehydration, which is formal Lewis acid catalyzed Friedel–Craftsreaction.
A H3PO3-catalyzed alkylation of phenols with alkenes is achieved in a facile, efficient, and selective manner. The reaction shows a unique selectivity, i.e., excellent regioselectivity, thorough suppression of overalkylation, without alkylation of a simple phenyl ring, and can selectively provide ortho-, meta-, or para-alkylated phenol derivatives in good to excellent yields. This feature along with
AH 3 PO 3催化的苯酚与烯烃的烷基化反应以简便,有效和选择性的方式实现。该反应显示出独特的选择性,即优异的区域选择性,彻底抑制了过度烷基化,而没有简单的苯环烷基化,并且可以有选择地提供邻位,间位或对位烷基化的苯酚衍生物,收率良好至优异。此功能以及温和的反应条件,敏感的官能团耐受性以及酚类生物活性化合物的按比例放大合成和后期修饰,使其成为酚类修饰的理想且实用的替代品。
Dehydrative Coupling of Benzylic Alcohols Catalyzed by Brønsted Acid/Lewis Base
作者:Marlene Böldl、Ivana Fleischer
DOI:10.1002/ejoc.201900965
日期:2019.9.15
A combination of Brønsted acid and Lewis base catalyses two dehydrative transformations of benzylic alcohols: homocoupling and hydroarylation.
We herein report a transition-metal-free cross-coupling between secondaryalkylhalides/mesylates and aryl/alkenylboronic acid, providing expedited access to a series of nonchiral/chiral coupling products in moderate to good yields. Stereospecific SN2-type coupling is developed for the first time with alkenylboronic acids as pure nucleophiles, offering an attractive alternative to the stereospecific
Transition-metal-catalyzed alkylation reactions of arenes have become a central transformation in organic synthesis. Herein, we report the first general strategy for alkylation of arenes with styrenes and alcohols catalyzed by carbon-based materials, exploiting the unique property of graphenes to produce valuable diarylalkane products in high yields and excellent regioselectivity. The protocol is characterized
芳烃的过渡金属催化烷基化反应已成为有机合成的核心转化。在此,我们报告了第一个由碳基材料催化的芳烃与苯乙烯和醇类烷基化的一般策略,利用石墨烯的独特性质以高产率和优异的区域选择性生产有价值的二芳基烷烃产品。该协议的特点是广泛的底物范围和出色的官能团耐受性。值得注意的是,该过程构成了石墨烯的第一个普遍应用,以利用锚定在 GO 表面上的极性官能团促进直接 CC 键的形成,从而为使用良性且易于获得的石墨烯材料进行一系列官能团烷基化打开了大门。