The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Lars Hagberg - One of the best experts on this subject based on the ideXlab platform.
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combining the 2 3 sigmatropic rearrangement and ring closing metathesis strategies for the synthesis of spirocyclic alkaloids a short and efficient route to Perhydrohistrionicotoxin
Tetrahedron, 1999Co-Authors: David Tanner, Lars Hagberg, Anders PoulsenAbstract:Abstract This paper describes the use of selenium-based [2,3] sigmatropic rearrangement in combination with ruthenium-catalyzed ring-closing metathesis (RCM) for the synthesis of azaspiro ring systems, as exemplified by the reactions of model substrates 5 and 6 . The methodology has been applied to a short and efficient formal total synthesis of the alkaloid (±)-Perhydrohistrionicotoxin ( 2 ). Thus, (±)-depentylPerhydrohistrionicotoxin, 1 , a known key intermediate for the synthesis of 2 , was synthesised from 2,3-epoxycyclohexan-1-one in 10 laboratory operations and ca. 20% overall yield. The synthetic route is potentially enantioselective, and key steps were the [2,3] sigmatropic rearrangement of 11 to 12 via the corresponding allylic selenide (86% yield) and ruthenium-catalyzed RCM of 13 to 14 (80%).
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A convergent enantioselective total synthesis of (−)-Perhydrohistrionicotoxin with an intramolecular imino ene-type reaction as a key step
Tetrahedron, 1998Co-Authors: David Tanner, Lars HagbergAbstract:Abstract A convergent enantioselective total synthesis of the neurotoxic spirocyclic alkaloid (−)-Perhydrohistrionicotoxin (2) is described. A Lewis acid-mediated intramolecular imine ene-type reaction was used for the key spirocyclisation step (14 to 3, with 3 being obtained as a single diastereoisomer). Spirocyclisation precursor 14 was prepared from enantiomerically pure ketone 13, itself available via an efficient one-pot, three-component, coupling reaction involving chiral electrophiles 9 and 10. The stereogenic centres of 9 and 10 derive in turn from Sharpless kinetic resolution, which allowed access to both chiral electrophiles from a common racemic precursor, 8.
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a convergent enantioselective total synthesis of Perhydrohistrionicotoxin with an intramolecular imino ene type reaction as a key step
Tetrahedron, 1998Co-Authors: David Tanner, Lars HagbergAbstract:Abstract A convergent enantioselective total synthesis of the neurotoxic spirocyclic alkaloid (−)-Perhydrohistrionicotoxin (2) is described. A Lewis acid-mediated intramolecular imine ene-type reaction was used for the key spirocyclisation step (14 to 3, with 3 being obtained as a single diastereoisomer). Spirocyclisation precursor 14 was prepared from enantiomerically pure ketone 13, itself available via an efficient one-pot, three-component, coupling reaction involving chiral electrophiles 9 and 10. The stereogenic centres of 9 and 10 derive in turn from Sharpless kinetic resolution, which allowed access to both chiral electrophiles from a common racemic precursor, 8.
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new synthetic routes to azaspiro alkaloids applications to the synthesis Perhydrohistrionicotoxin
1998Co-Authors: Lars HagbergAbstract:New synthetic routes to azaspiro alkaloids : applications to the synthesis Perhydrohistrionicotoxin
Cheol Won Park - One of the best experts on this subject based on the ideXlab platform.
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Construction of the Tricyclo
Journal of Organic Chemistry, 2000Co-Authors: Phil Jong Shim, Cheol Won Park, Sungwoo HongAbstract:: Histrionicotoxin derivatives have long been attractive targets for synthetic chemists as a result of their useful neurophysical properties, low natural abundance, and the unique structural features of the azaspiro[5.5]undecane ring system. Utilizing our tandem pinacol rearrangement-ene strategy and regiospecific Baeyer-Villiger oxidation as key steps, we have successfully synthesized an advanced synthetic intermediate, spiro[5.4]decane 4, which has previously been converted to (+/-)-Perhydrohistrionicotoxin (5b). Pinacol rearrangement of simple Diels-Alder derived bicyclo[2.2.2]octene system 2a, followed by an ene reaction, led to the efficient formation of the highly fuctionalized tricyclo[5.3.1.0(1,5)]undecane system 1a. This tricyclic system 1a was selectively transformed into spiro[5. 4]decane system 4 via a regiospecific Baeyer-Villiger oxidation reaction. We also report the results of systematic studies of Baeyer-Villiger oxidation reactions of tricyclo[5.3.1.0(1, 5)]undecanone systems to elucidate the origin of the regioselectivity of this process.
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Construction of the tricyclo[5.3.1.01,5]undecane system by a tandem pinacol rearrangement–ene strategy: a formal synthesis of (±)-Perhydrohistrionicotoxin
Chemical Communications, 1997Co-Authors: Sungwoo Hong, Cheol Won ParkAbstract:An advanced synthetic intermediate 4 for Perhydrohistrionicotoxin 5 has been synthesized utilizing a novel tandem pinacol rearrangement–ene reaction as a key step.
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construction of the tricyclo 5 3 1 01 5 undecane system by a tandem pinacol rearrangement ene strategy a formal synthesis of Perhydrohistrionicotoxin
Chemical Communications, 1997Co-Authors: Sungwoo Hong, Cheol Won ParkAbstract:An advanced synthetic intermediate 4 for Perhydrohistrionicotoxin 5 has been synthesized utilizing a novel tandem pinacol rearrangement–ene reaction as a key step.
Joseph P A Harrity - One of the best experts on this subject based on the ideXlab platform.
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formal synthesis of Perhydrohistrionicotoxin via a stepwise 3 3 annelation strategy
Tetrahedron Letters, 2006Co-Authors: Olivier Y Provoost, Simon J Hedley, Andrew J Hazelwood, Joseph P A HarrityAbstract:Abstract A formal synthesis of (±)-Perhydrohistrionicotoxin is described that includes a highly diastereoselective modified Sharpless aziridination and a stepwise [3+3] annelation reaction for the stereoselective construction of the key spiropiperidine motif.
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Formal synthesis of (±)-Perhydrohistrionicotoxin via a stepwise [3+3] annelation strategy
Tetrahedron Letters, 2006Co-Authors: Olivier Y Provoost, Simon J Hedley, Andrew J Hazelwood, Joseph P A HarrityAbstract:Abstract A formal synthesis of (±)-Perhydrohistrionicotoxin is described that includes a highly diastereoselective modified Sharpless aziridination and a stepwise [3+3] annelation reaction for the stereoselective construction of the key spiropiperidine motif.
Sungwoo Hong - One of the best experts on this subject based on the ideXlab platform.
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Construction of the Tricyclo
Journal of Organic Chemistry, 2000Co-Authors: Phil Jong Shim, Cheol Won Park, Sungwoo HongAbstract:: Histrionicotoxin derivatives have long been attractive targets for synthetic chemists as a result of their useful neurophysical properties, low natural abundance, and the unique structural features of the azaspiro[5.5]undecane ring system. Utilizing our tandem pinacol rearrangement-ene strategy and regiospecific Baeyer-Villiger oxidation as key steps, we have successfully synthesized an advanced synthetic intermediate, spiro[5.4]decane 4, which has previously been converted to (+/-)-Perhydrohistrionicotoxin (5b). Pinacol rearrangement of simple Diels-Alder derived bicyclo[2.2.2]octene system 2a, followed by an ene reaction, led to the efficient formation of the highly fuctionalized tricyclo[5.3.1.0(1,5)]undecane system 1a. This tricyclic system 1a was selectively transformed into spiro[5. 4]decane system 4 via a regiospecific Baeyer-Villiger oxidation reaction. We also report the results of systematic studies of Baeyer-Villiger oxidation reactions of tricyclo[5.3.1.0(1, 5)]undecanone systems to elucidate the origin of the regioselectivity of this process.
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Construction of the tricyclo[5.3.1.01,5]undecane system by a tandem pinacol rearrangement–ene strategy: a formal synthesis of (±)-Perhydrohistrionicotoxin
Chemical Communications, 1997Co-Authors: Sungwoo Hong, Cheol Won ParkAbstract:An advanced synthetic intermediate 4 for Perhydrohistrionicotoxin 5 has been synthesized utilizing a novel tandem pinacol rearrangement–ene reaction as a key step.
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construction of the tricyclo 5 3 1 01 5 undecane system by a tandem pinacol rearrangement ene strategy a formal synthesis of Perhydrohistrionicotoxin
Chemical Communications, 1997Co-Authors: Sungwoo Hong, Cheol Won ParkAbstract:An advanced synthetic intermediate 4 for Perhydrohistrionicotoxin 5 has been synthesized utilizing a novel tandem pinacol rearrangement–ene reaction as a key step.
Olivier Y Provoost - One of the best experts on this subject based on the ideXlab platform.
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formal synthesis of Perhydrohistrionicotoxin via a stepwise 3 3 annelation strategy
Tetrahedron Letters, 2006Co-Authors: Olivier Y Provoost, Simon J Hedley, Andrew J Hazelwood, Joseph P A HarrityAbstract:Abstract A formal synthesis of (±)-Perhydrohistrionicotoxin is described that includes a highly diastereoselective modified Sharpless aziridination and a stepwise [3+3] annelation reaction for the stereoselective construction of the key spiropiperidine motif.
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Formal synthesis of (±)-Perhydrohistrionicotoxin via a stepwise [3+3] annelation strategy
Tetrahedron Letters, 2006Co-Authors: Olivier Y Provoost, Simon J Hedley, Andrew J Hazelwood, Joseph P A HarrityAbstract:Abstract A formal synthesis of (±)-Perhydrohistrionicotoxin is described that includes a highly diastereoselective modified Sharpless aziridination and a stepwise [3+3] annelation reaction for the stereoselective construction of the key spiropiperidine motif.