Cerium-Catalyzed α-Hydroxylation Reactions of α-Cyclopropyl β-Dicarbonyl Compounds with Molecular Oxygen
作者:Jens Christoffers、Thomas Kauf、Thomas Werner、Michael Rössle
DOI:10.1002/ejoc.200600061
日期:2006.6
Three α-cyclopropyl β-dicarbonyl compounds have been used as probes for α-radicals as electrophilic reaction intermediates in a cerium-catalyzed α-hydroxylation reaction with molecular oxygen. Since the cyclopropyl group did not ring-open to products with a butenyl moiety, but was retained in the products, a localized unpaired electron at the α position can be excluded during the course of the reaction
三种 α-环丙基 β-二羰基化合物已被用作探针,用于在铈催化的与分子氧的 α-羟基化反应中作为亲电反应中间体的 α-自由基。由于环丙基不会对带有丁烯基部分的产物开环,而是保留在产物中,因此在反应过程中可以排除α位的局部未配对电子。α-环丙基取代的底物通过羟醛或克莱森反应制备。制备了具有 α-甲基、α-异丙基和 α-叔丁基取代基的其他底物,并在 α-羟基化条件下进行转化,以估计空间位阻对反应产率的影响。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)