Vincadifformine and its 10-substituted analogs give in good yields 16-nitro indolenines of which the reactivity has been studied. By a two step process (demethoxycarbonylation and chloration on C16) nitro-indolenine 2b leads to gem-chloro-nitro 6. By an other two step sequence (NaBH3CN, NaH) nitro-indo-lenine 2c yields compound 10 via a 16→ 1 COOCH3 migration. By heating compounds 6 and 10 in CF3COOH, rearranged products are ...