Starting from vindoline (2) and 7-methoxycarbonylazoninoindole derivatives 7, a new concept for the synthesis of vinblastine 1a type alkaloids with natural C (16') stereochemistry is described. Using lactam 8 and chloroindolenine 9 as key intermediatea a stereocontrolled coupling between the dihydroindole and indole subunits under formation of 10 should be achieved. Methanolysis of 10 and intramolecular No-alkylation of the resulting 12a should ...
![2,4,5,8-tetrahydro-1H-azonino[5,4-b]indole-3-carbonitrile Structure](https://image.chemsrc.com/caspic/344/114476-08-3.png)