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 in | Tetrahedron: asymmetry Vol. 18; no. 3; pp. 406 - 413 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
28.02.2007
|
Online Access | Get full text |
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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. |
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ISSN: | 0957-4166 1362-511X |
DOI: | 10.1016/j.tetasy.2007.01.014 |