Short synthetic route to (±)-geissoschizine

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

doi:10.1016/0040-4020(96)00292-x

Cited by 11 publications

(1 citation statement)

References 12 publications

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“…However, from a literature survey, it appears that the routes towards desethyleburnamonine 1 are rather cumbersome: (i) Potier reported a short access to 1, using the reductive cyclization of a pyridinium salt in the presence of hydrogen; [6][7][8] (ii) Lounasmaa disclosed several routes towards 1 and analogues based on the Potier-Polonovski reaction; [9][10][11][12][13] (iii) later Massiot reported on the isomerization-cyclization of indolyl-tetrahydropiperidine 2, assisted by Rh I . [14] However, all these sequences are incompatible for scale-up, mainly because of tedious purification steps and low overall yields.…”

Section: Introductionmentioning

confidence: 99%

Expeditious Route Towards (±)‐Desethyleburnamonine, a Precursor of (±)‐Vindeburnol

Jung-Deyon¹,

Giethlen²,

Mann³

2011

Eur J Org Chem

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An expeditious route to (±)‐desethyleburnamonine (1), a direct precursor of vindeburnol, is reported. Microwave irradiation of an indolo‐tetrahydropyridine ethyl ester 2 in CH3CN in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) gave the pentacyclic (±)‐desethyleburnamonine in a one‐pot process. Experimental evidence support an allylamine–enamine isomerization, followed by a rare Pictet–Spengler condensation in basic media. From commercially available 3‐(2‐bromo‐ethyl)indole and ethyl pyridin‐3‐yl acetate, (±)‐desethyleburnamonine was obtained in 52 % yield over three steps.

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Section: Introductionmentioning

confidence: 99%

Expeditious Route Towards (±)‐Desethyleburnamonine, a Precursor of (±)‐Vindeburnol

Jung-Deyon¹,

Giethlen²,

Mann³

2011

Eur J Org Chem

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Total Syntheses of (+)‐Villocarine A, (−)‐Apogeissoschizine, and (+)‐Geissoschizine

Sakamoto

Kitajima

Ishikawa

2023

Chemistry A European J

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Total syntheses of geissoschizine‐type monoterpenoid indole alkaloids (MTIAs) are reported. An intramolecular Pictet‐Spengler cyclization was developed for the selective construction of the 3R stereocenter. The first total synthesis of (+)‐villocarine A was then achieved. Furthermore, the first total synthesis of the highly strained (−)‐apogeissoschizine was also accomplished in an aza‐Michael cyclization/E1cB elimination/stereoselective olefin isomerization sequence. Finally, (+)‐geissoschizine, a common biosynthetic intermediate of MTIAs, was obtained from apogeissoschizine through ring‐opening along with a release of ring strain.

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