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The alkaloids (-)-pseudotabersonine (I), (-)-pseudovincadifformine (II) and (+)-coronaridine (III) are synthesized from commercially available (+)-catharanthine by Ir-catalyzed photoredox reaction.

Condensation of indoloazepines bearing the chiral N b -substituents: 1-( R )-naphthyl-α-ethyl, [1-( R )-[( S )-2-(diphenylphospheno)ferrocenyl]-ethyl], or 2,3-( R )-ferroceno-6,6-dimethyl-1-( S )-cyclohexyl, with 4-(1,3-dioxolan-2-yl)-hexanal, or with 4-(1,3-dioxolan-2-yl)-6-methoxyhexanal, gave diastereoselectively, through a secodine-type intramolecular Diels–Alder reaction, tetracyclic intermediates that could be carried to (−)-coronaridine or to the important anti-addictive (−)-18-methoxycoronaridine. The 2,3-( R )-ferroceno-6,6-dimethyl-1-( S )-cyclohexyl chiral auxiliary was most effective, providing >99% ee of a tetracyclic intermediate after removal of the chiral auxiliary group.

A new sarpagine-type alkaloid with N-oxide group, called ervahainanmine, and three known ones including coronaridine, 19(S)-heyneanineguan, and coronaridine hydroxyindolenineguan were isolated from the stems of Evratamia hainanensis. The structure was established by spectroscopic methods, especially 2D NMR techniques.

Six indole alkaloids were isolated from the stems of Ervatamia yunnanensis. Among them, yunnanensine (I) is new. The other five are known alkaloids, namely: 19,20-E-vallesamine (II), 19s-heyneanine (III), ibogaine (IV), ibogamine (V), coronaridine (VI). The structural elucidation of the alkaloids was based on spectral means.

Ten indole alkaloids from the chloroform extract of stalk of Tabernaemontana australis (Muell. Arg) Miers were tentatively identified by GC–MS, viz. , coronaridine ( 1 ), voacangine ( 2 ), voacangine hydroxyindolenine ( 3 ), rupicoline ( 4 ), ibogamine ( 5 ), ibogaine ( 6 ), ibogaline ( 7 ), desethyl-voacangine ( 8) , voachalotine ( 9 ), and affinisine ( 10 ). Of these, the first four were isolated by silica gel open column chromatography, identified by uni- and bidimensional NMR, IR, MS and showed anti-cholinesterasic activity at the same concentration as the reference compounds physostigmine and galanthamine (detection limit of 0.01 mM) by TLC assay using the modified Ellman’s method.