A detailed study involving the Polonovski-type coupling of vindoline (2) with several novel catharanthine derivatives is described. Coupling of vindoline (2) with the N-oxide intermediate of 3β,4β-epoxydihydrocatharanthine (1) provides a laboratory synthesis of the bisindole alkaloid leurosine (3, R=CO2CH3) and an unambiguous proof of the stereochemistry of the epoxide function in that alkaloid. The coupling of 2 with the N-oxides of 3α,4α-epoxydihydrocatharanthine (4) and 4α-hydroxydihydrocatharanthinic acid lactone (6) provide the rearranged bisindole products 5, 7, and 8.

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Studies describing the preparation of various derivatives of vinblastine and vincristine are presented. Vindoline (3) is transformed into a series of derivatives and the latter via Polonovski-type coupling with catharanthine (2) provide the bisindole alkaloid derivatives of the vinblastine series. Selective Jones' oxidation transforms the vinblastine family into the corresponding vincristine derivatives.

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