Abstract
In the past, much effort has been focused on the solution of the problem of the configurations of the iboga alkaloids. The present knowledge in this field is based on two independent X-ray diffraction studies dealing with cleavamine methiodide (prepared from catharanthine (IV) and with the dimeric leurocristine methiodide. The same absolute configuration on the corresponding atoms was found in both compounds. On the other hand, the enantiometric configuration was suggested for a degradation product of ibogaine (1X) by means of optical rotatory dispersion measurements. However, at that time, this finding was considered not fully convincing. Finally, the series of reactions correlating catharanthine (VI) with coronaridine (I) and ibogaine (VIII) were published. Since the optical activity of the resulting coronaridine and ibogamine is not known, the correlations cannot be exploited for the absolute configuration studies.
