Total synthesis of benzo [c] phenanthridine alkaloids based on a microwave-assisted electrocyclic reaction of the aza 6π-electron system and structural revision of …
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 system, which was ...