An efficient diastereoselective trans cyclopropanation of 3-alkylidene oxindoles with in situ generated α-diazo carbonyl compounds or α,β-unsaturated diazo compounds under metal-free conditions has been developed to synthesize 3-spirocyclopropyl-2-oxindole derivatives. The procedure is based on the 1,3-dipolar character of the corresponding diazo compounds under base-catalyzed conditions. The method has a wide substrate scope and uses easily available starting materials.
开发了一种高效的立体选择性反式环丙烷化反应,用于合成3-烷基亚基氧化吲哚与现场生成的α-重氮羰基化合物或α,β-不饱和重氮化合物的反应,无需金属条件即可合成3-螺环丙基-2-氧化吲哚衍生物。该方法基于相应重氮化合物在碱催化条件下的1,3-偶极特性。该方法具有广泛的底物范围,并使用易于获得的起始材料。