Ein neuer Abbau des Indolalkaloids Kopsin; chemische Korrelierung der Alkaloide vom Kopsin- und Pleiocarpin-Typ mit Minovincin

A new chemical degradation of (–)-kopsine is described which completely confirms the structure of this alkaloid. Correlation of (–)-aspidofractinine, (–)-pleiocarpine and (–)-kopsine with (–)-minovincine establishes the absolute stereochemistry of these bases. It appears that, in contrast to the aspidospermine group, all alkaloids containing the aspidofractinine skeleton possess the same absolute stereochemistry.