Addition of Organometallic Reagents to Chiral N-Methoxylactams: Enantioselective Syntheses of Pyrrolidines and Piperidines
Addition of Organometallic Reagents to Chiral N-Methoxylactams: Enantioselective Syntheses of Pyrrolidines and Piperidines
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DOI：
10.1002/chem.201302735
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发表时间：
2013-12-02
影响因子：
4.3
通讯作者：
Helmchen, Guenter
中科院分区：
文献类型：
--
作者：
Jaekel, Mascha;Qu, Jianping;Helmchen, Guenter
利用铱催化的烯丙基取代反应制备了N-烯丙基异羟肟酸衍生物，该衍生物适合于闭环复分解反应，得到N-甲基内酰胺。这些衍生物与格氏试剂或有机锂化合物反应生成半缩醛，半缩醛可通过酰亚胺中间体非对映选择性还原，分别得到2，6-或2，5-位取代的顺式哌啶或顺式吡咯烷。此外，具有季碳中心的化合物可以通过与氰化钾/AcOH的相应反应来合成。并将其应用于生物碱（-）-209D和（+）-丙茶碱的合成。
Enantioselective iridium-catalyzed allylic substitutions were used to prepare N-allyl hydroxamic acid derivatives that were suitable for ring-closing metathesis, giving N-methoxylactams. Reactions of these derivatives with Grignard or organolithium compounds gave hemiaminals, which could be reduced diastereoselectively via acyliminium intermediates to give cis-piperidines or cis-pyrrolidines with substituents in the 2,6- or 2,5-positions, respectively. In addition, compounds with a quaternary carbon center could be synthesized by corresponding reactions with potassium cyanide/AcOH. The procedures were applied in the syntheses of alkaloids (-)-209D and (+)-prosophylline.