A Ring Expansion−Annulation Strategy for the Synthesis of Substituted Azulenes. Preparation and Suzuki Coupling Reactions of 1-Azulenyl Triflates
作者:John L. Kane、Kevin M. Shea、Aimee L. Crombie、Rick L. Danheiser
DOI:10.1021/ol0156897
日期:2001.4.1
[structure: see text]. A new strategy for the synthesis of substituted azulenes is reported, based on the reaction of beta'-bromo-alpha-diazo ketones with rhodium carboxylates. The key transformation involves intramolecular addition of a rhodium carbenoid to an arene pi-bond, electrocyclic ring opening, beta-elimination, tautomerization, and trapping to produce 1-hydroxyazulene derivatives. The synthetic
[结构:见文字]。基于β'-溴-α-重氮酮与羧酸铑的反应,已报道了一种合成取代的天青烯的新策略。关键的转化涉及将铑类胡萝卜素分子内添加到芳烃pi键上,电环开环,β消除,互变异构化和捕获以生成1-羟基氮杂烯衍生物。该方法的合成效用通过三氟甲磺酸酯衍生物参与Suzuki偶联反应的能力得以增强,如抗溃疡药白蛋白钠(KT1-32)的合成所示。