Tosylhydrazide-Promoted Diastereoselective Intramolecular 1,3-Dipolar Cycloadditions: Synthesis of Tetrahydropyrrolo[3,4-<i>c</i>]pyrazoles
作者:Raquel Barroso、Maria Escribano、Maria-Paz Cabal、Carlos Valdés
DOI:10.1002/ejoc.201301587
日期:2014.3
α-amino acids, which are first transformed into N-allyl-α-amino ketones through conventional methodologies. Then, a one-pot sequence that involves formation of a tosylhydrazone from the ketone, base-induced decomposition of the hydrazone, and intramolecular 1,3-dipolar cycloaddition of the diazo compound generated, gives rise to the bicyclic systems with total diastereoselectivity and high preservation
描述了通过分子内 1,3-偶极环加成非对映选择性合成四氢吡咯并 [3,4-c] 吡唑。合成路线的起始原料是 N-Boc 保护的 α-氨基酸,首先通过常规方法将其转化为 N-烯丙基-α-氨基酮。然后,包括从酮形成甲苯磺酰腙、腙的碱诱导分解和生成的重氮化合物的分子内 1,3-偶极环加成的一锅序列产生具有总非对映选择性和高的双环系统保持对映体纯度。然而,使用 α-氨基醛的类似方法缺乏立体选择性。已经进行了 DFT 计算建模以解释两种类型系统的不同行为。