Enantioselective synthesis of some tetrahydroisoquinoline and tetrahydro-β-carboline alkaloids

Four alkaloids: ( R)-(+)-cryspine A 5, ( R)-(+)-octahydroindolo[2,3- a]quinolizidine 8, ( R)-(+)-harmicine 19 and ( R)-(+)-desbromoarborescidine 22 were prepared via the asymmetric transfer hydrogenation reaction of a prochiral enamine (iminium salt). The enantiomeric excesses of the isolated alkalo...

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Published inTetrahedron: asymmetry Vol. 18; no. 3; pp. 406 - 413
Main Authors Szawkało, Joanna, Czarnocki, Stefan J., Zawadzka, Anna, Wojtasiewicz, Krystyna, Leniewski, Andrzej, Maurin, Jan K., Czarnocki, Zbigniew, Drabowicz, Józef
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 28.02.2007
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Summary:Four alkaloids: ( R)-(+)-cryspine A 5, ( R)-(+)-octahydroindolo[2,3- a]quinolizidine 8, ( R)-(+)-harmicine 19 and ( R)-(+)-desbromoarborescidine 22 were prepared via the asymmetric transfer hydrogenation reaction of a prochiral enamine (iminium salt). The enantiomeric excesses of the isolated alkaloids were determined from their 1H NMR spectra measured in the presence of (+)-( R)- tert-butylphenylphosphinothio(seleno)ic acids as chiral solvating agents. The absolute configurations at the newly created stereogenic carbon atoms were confirmed, in all cases, by X-ray crystallography.
ISSN:0957-4166
1362-511X
DOI:10.1016/j.tetasy.2007.01.014