Gram Scale Total Synthesis of 2-Hydroxy-3-methylcarbazole, Pyrano[3,2-a]carbazole and Prenylcarbazole Alkaloids
Gram Scale Total Synthesis of 2-Hydroxy-3-methylcarbazole, Pyrano[3,2-a]carbazole and Prenylcarbazole Alkaloids
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2-羟基-3-甲基咔唑、吡喃并[3,2-a]咔唑和异戊二烯咔唑生物碱的克级全合成
DOI：
10.1002/ejoc.201500783
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发表时间：
2015-09-01
影响因子：
2.8
通讯作者：
Ma, Shengming
中科院分区：
文献类型：
--
作者：
Dai, Jianxin;Ma, Dengke;Ma, Shengming
天然存在的咔唑类生物碱，包括2-羟基-3-甲基咔唑、吡喃[3,2-a]咔唑类生物碱（吉林宁碱和穆拉卡因）和戊基咔唑类生物碱（mukoenine-A和heptaphyline）已按克级合成。这些合成的关键化合物是9-苄基-2-甲氧基-3-甲基咔唑，它是由现成的甲氧基丙二烯和吲哚-2-乙醛通过高效的金催化环化反应制备的。用简洁的PhB(OH)2介导的3-甲基丁-2-烯醛分子间环化反应合成了吉立宁滨和莫拉嘧啶。钯催化烯丙基化/Claisen重排是制备mukoenine-A和hephiline的最佳途径。
Naturally occurring carbazole alkaloids including 2-hydroxy-3-methylcarbazole, pyrano[3,2-a]carbazole alkaloids (girinimbine and murrayacine) and prenylcarbazole alkaloids (mukoenine-A and heptaphylline) have been synthesized on gram scale. The key compound in these syntheses is 9-benzyl-2-methoxy-3-methylcarbazole, which was prepared by an efficient Au-catalyzed cyclization reaction of readily available methoxypropadiene and indole-2-carbaldehyde. Girinimbine and murrayacine were synthesized by a concise PhB(OH)2-mediated intermolecular cyclization with 3-methylbut-2-enal. Palladium-catalyzed allylation/Claisen rearrangement proved to be the best route to mukoenine-A and heptaphylline.