Functionalized fluoroalkyl heterocycles by 1,3-dipolar cycloadditions with γ-fluoro-α-nitroalkenes
作者:Serena Bigotti、Luciana Malpezzi、Marco Molteni、Andrea Mele、Walter Panzeri、Matteo Zanda
DOI:10.1016/j.tetlet.2009.03.059
日期:2009.5
Differently fluorinated γ-fluoro-α-nitroalkenes 1a–d are effective dipolarophiles in 1,3-dipolar cycloadditions with nitrones and azomethine ylides, respectively, providing fluoroalkyl isoxazolidines 3–12 and pyrrolidines 13–14 in good to excellent yields, with nearly complete regiocontrol and total diastereocontrol in favor of the isomers having anti-configuration of the nitro- and fluoroalkyl-substituted
不同氟化γ氟-α-硝基烯烃1A - d是有效dipolarophiles分别与硝酮和甲亚胺叶立德,1,3-偶极环加成,从而提供氟代异恶唑烷3 - 12和吡咯烷13 - 14以良好至优异的产率,以几乎完全的区域控制和总非对映控制,有利于对硝基和氟烷基取代的碳中心具有反构型的异构体。3,4-顺式-环加合物通常以更高的比例产生。在手性硝酮如2e的情况下,非对映异构控制非常高,有利于内环双环加合物11被观测到。有趣的是,在大多数情况下,氯二氟硝基烯烃1b被发现提供了最佳的非对映异构控制。