Total synthesis of benzo[c]phenanthridine alkaloids based on a microwave-assisted electrocyclic reaction of the aza 6π-electron system and structural revision of broussonpapyrine
作者:Yuhsuke Ishihara、Shuhei Azuma、Tominari Choshi、Kakujirou Kohno、Kanako Ono、Hiroyuki Tsutsumi、Takashi Ishizu、Satoshi Hibino
DOI:10.1016/j.tet.2010.11.066
日期:2011.2
Total syntheses of the des-N-methyl (nor) type of benzo[c]phenanthridine alkaloids 1a–f and 19 and benzo[c]phenanthridine alkaloids, chelerythrine (2d), and broussonpapyrine (2f) were achieved. The key step was the construction of tetracyclic 10,11-dihydrobenzo[c]phenanthridines using a microwave-assisted electrocyclic reaction of the 2-cycloalkenylbenzaldoxime methyl ether 4 as an aza 6π-electron
合成了苯并[ c ]菲啶生物碱1a - f和19和苯并[ c ]菲啶生物碱,白屈菜红碱(2d)和布鲁索帕林(2f)的des- N-甲基(nor)型。关键步骤是利用微波辅助的2-环烯基苯甲醛肟基甲基醚4作为氮杂6π电子体系的微波辅助反应,构建四环10,11-二氢苯并[ c ]菲啶,该过程分两步从Suzuki- 2-溴苯甲醛6的宫浦交叉偶联反应与2-(3,4-二氢-6,7-亚甲基二氧基萘基)硼酸频哪醇酯7。另外,确定了溴索品比林(2f)(2,3,9,10-四加氧型)的确切结构为白屈菜红碱(2d)。