Total Synthesis of the Strychnos Alkaloid (+)-Minfiensine: Tandem Enantioselective Intramolecular Heck−Iminium Ion Cyclization
作者:Amy B. Dounay、Philip G. Humphreys、Larry E. Overman、Aaron D. Wrobleski
DOI:10.1021/ja800163v
日期:2008.4.1
more concise total synthesis, an intramolecular palladium-catalyzed ketone enolate vinyl iodide coupling was employed to construct the final ring of (+)-minfiensine. This second-generation total synthesis of enantiopure (+)-minfiensine was accomplished in 6.5% overall yield and 15 steps from 1,2-cyclohexanedione and anisidine 13. A distinctive feature of this sequence is the use of palladium-catalyzed
A 1,2,3,4-四氢-9a,4a-(亚氨基乙醇)-9H-咔唑 (4) 是马钱子生物碱 minfiensine (1) 和 akuammiline 生物碱如长春花碱 (5) 和乙胺嘧啶 ( 6). 开发了级联催化不对称 Heck-iminium 环化,可快速提供高对映体纯度的 3,4-二氢-9a,4a-(亚氨基乙醇)-9H-咔唑。开发了两个序列用于将 3,4-dihydro-9a,4a-(iminoethano)-9H-carbazole 27 推进到 (+)-minfiensine。在我们的第一代方法中,采用还原性 Heck 环化来形成 (+)-minfiensine 的第五个环。在第二个更简洁的全合成中,采用分子内钯催化的酮烯醇乙烯基碘偶联来构建 (+)-minfiensine 的最终环。