Preparation and Conformational Study of Deformyl-Z- and Deformyl-E-geissoschizine Epimers and Na-Boc Derivatives, and Their Nb-Oxides

Lounasmaa, Mauri; Jokela, Reija; Hanhinen, Pirjo; Laine, Christiane; Anttila, U.

doi:10.3987/com-96-7503

Cited by 5 publications

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“…This would appear to be the first example of the successful use of orthomalonates in Claisen ester rearrangements. By use of methods previously published, 20, 21 Lounasmaa and his co-workers have prepared 22 the four possible deformylgeissoschizines 21, together with their N a tertbutoxycarbonyl (N a -Boc) derivatives, their cis N b -oxides, and two of their trans N b -oxides. The predominant conformations of these compounds were determined from their NMR spectra, full details of which were given, together with assignments.…”

Section: Monoterpenoid Indole Alkaloids 21 Corynantheine Heteroyohimb...mentioning

confidence: 99%

Recent progress in the chemistry of the monoterpenoid indole alkaloids

Saxton¹

1997

Nat. Prod. Rep.

234

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Section: Monoterpenoid Indole Alkaloids 21 Corynantheine Heteroyohimb...mentioning

confidence: 99%

Recent progress in the chemistry of the monoterpenoid indole alkaloids

Saxton¹

1997

Nat. Prod. Rep.

234

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The Double‐Bond Configuration of Corynanthean Alkaloids and Its Impact on Monoterpenoid Indole Alkaloid Biosynthesis

Eckermann

Gaich

2016

Chemistry A European J

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Experimental evidence is provided for the coherence of the double-bond geometry and the occurrence of "secondary cyclizations" in the biosynthesis of monoterpenoid indole alkaloids. Biosynthetically, akuammiline, C-mavacurine, and Strychnos alkaloids are proposed to be derived from the corynanthean alkaloid geissoschizine, a key intermediate in the biosynthetic pathway of these monoterpenoid indole alkaloids. This process occurs by so-called "secondary cyclizations" from geissoschizine or its derivatives. Although corynanthean alkaloids like geissoschizine incorporate E or Z double bonds located at C19-C20, the alkaloids downstream in the biosynthesis exclusively exhibit the E double bond. This study shows that secondary cyclizations preferentially occur with the E isomer of geissoschizine or its derivatives. This is attributed to the flexibility of the quinolizidine system of the corynanthean alkaloids, which can adopt a cis or trans conformation. For the secondary cyclization to take place, the cis-quinolizidine conformation is required. Experimental evidence supports the hypothesis that the E double bond of geissoschizine induces the cis conformation, whereas the Z double bond induces the trans conformation, which prohibits secondary cyclization of the Z compounds.

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Studies on the biomimetic preparation of the sarpagan ring system. Attempts to apply the spontaneous “biogenetic-type cyclization” of van Tamelen to bond formation between C-5 and C-16 in the corynantheine series

Lounasmaa

Hanhinen

1996

Tetrahedron

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Preparation and Conformational Study of Deformyl-Z- and Deformyl-E-geissoschizine Epimers and Na-Boc Derivatives, and Their Nb-Oxides

Cited by 5 publications

References 0 publications

Recent progress in the chemistry of the monoterpenoid indole alkaloids

Recent progress in the chemistry of the monoterpenoid indole alkaloids

The Double‐Bond Configuration of Corynanthean Alkaloids and Its Impact on Monoterpenoid Indole Alkaloid Biosynthesis

Studies on the biomimetic preparation of the sarpagan ring system. Attempts to apply the spontaneous “biogenetic-type cyclization” of van Tamelen to bond formation between C-5 and C-16 in the corynantheine series

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