Diastereoselective tandem addition-cyclization reactions of unsaturated tertiary amines initiated by photochemical electron transfer (PET)
Diastereoselective tandem addition-cyclization reactions of unsaturated tertiary amines initiated by photochemical electron transfer (PET)
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DOI：
10.1021/jo001166l
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发表时间：
2000-12-15
影响因子：
3.6
通讯作者：
Pete, JP
中科院分区：
文献类型：
--
作者：
Bertrand, S;Hoffmann, N;Pete, JP
通过串联反应获得多环分子和四氢喹啉，其中or-氨基烷基自由基非对映选择性加成到(5R)-5-薄荷氧基-2[5H]-呋喃酮1上。1上的表面非对映选择性大于或等于90%。 α-氨基烷基自由基是通过光化学诱导的电子转移由叔胺产生的。当使用N,N-二烷基苯胺19作为起始叔胺时，涉及重芳构化步骤并且观察到1的重要副反应。一项涉及起始胺同位素标记的机制研究表明，副产物是由重芳构化过程中 1 的还原产生的。通过简单地将丙酮或环戊酮作为温和氧化剂添加到反应混合物中，获得了反应的有效优化。在这些条件下，呋喃酮1还原产生的副产物被完全抑制，并且四氢喹啉21a-i、22a-f和26g-i的产率加倍。
Polycyclic molecules and tetrahydroquinoleines were obtained in a tandem reaction involving the diastereoselective addition of or-aminoalkyl radicals to (5R)-5-menthyloxy-2[5H]-furanone 1. The facial diastereoselectivity on 1 is greater than or equal to 90%. The alpha -aminoalkyl radicals were produced from tertiary amines by photachemical-induced electron transfer. When N,N-dialkylanilines 19 were used as starting tertiary amines, a rearomatization step was involved and important side reactions of 1 were observed. A mechanistic study involving isotopic labeling of the starting amine indicated that the byproducts resulted from reduction of 1 during the rearomatization process. An efficient optimization of the reaction was obtained by simply adding acetone or cyclopentanone as mild oxidants to the reaction mixture. The side products resulting from reduction of the furanone 1 were completely suppressed under these conditions, and the yields of the tettahydroquinolines 21a-i, 22a-f, and 26g-i were doubled.