Visible light photoredox and Polonovsld-Potier cyclizations for the synthesis of (±)-5-epi-cermizine C and (±)-epimyrtine
Visible light photoredox and Polonovsld-Potier cyclizations for the synthesis of (±)-5-epi-cermizine C and (±)-epimyrtine
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DOI：
10.1016/j.tetlet.2016.10.007
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发表时间：
2016-11-16
影响因子：
1.8
通讯作者：
Marvin, Christopher C.
中科院分区：
文献类型：
--
作者：
Benimana, Shami Eden;Cromwell, Nicholle E.;Marvin, Christopher C.
喹里西啶生物碱 Epi-cermizine C 和 Epimyrtine 由市售材料通过 5-6 个步骤从常见中间体合成。关键步骤涉及烯丙基硅烷与叔胺氧化形成的亚胺离子的环化。通过可见光光氧化还原催化或通过化学计量的 Polonovski-Potier 条件促进氧化成环。两种方法之间的非对映选择性存在适度差异，对于 Polonovski 路线，光氧化还原以 4.7:1 dr 与 2:1 dr 提供关键的喹啉西啶中间体。 (C) 2016 Elsevier Ltd. 保留所有权利。
Quinolizidine alkaloids epi-cermizine C and epimyrtine were synthesized from a common intermediate in 5-6 steps from commercially available materials. The key step involved an allylsilane cyclization with an iminium ion formed by oxidation of a tertiary amine. Oxidative annulation was promoted either catalytically by visible light photoredox catalysis or by stoichiometric Polonovski-Potier conditions. There was a modest difference in diastereoselectivity between the two methods, with photoredox providing the key quinolizidine intermediate in 4.7:1 dr versus 2:1 dr for the Polonovski route. (C) 2016 Elsevier Ltd. All rights reserved.