Syntheses and X-Ray Crystal Structures of Tricyclic Ketones Containing Trans-Fused Azabicyclo[3.3.0]octane Units

Mori, Miwako; Saitoh, Fumihiko; Uesaka, Noriaki; Okamura, Koji; Date, Tadamasa

doi:10.1021/jo00096a050

Cited by 25 publications

(16 citation statements)

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“…To discuss the differences between the old and the new configurations of the palauamines, tetrabromostyloguanidine (22) will be used as a model in the following discussion.…”

Section: Isolation Of the Styloguanidines And Structural Revision Of mentioning

confidence: 99%

“…In 1993, Scheuer and co-workers reported the structure of palauamine (1, Scheme 1), [7] an architecturally interesting alkaloid from the same family. Since then, the pyrroleimidazole alkaloid family (Scheme 2) has been steadily growing, with the isolation of many analogues of sceptrin (3)(4)(5)(6)(7), [8] the ageliferins (8)(9)(10), [9] the nagelamides (11-13), [10] the axinellamines (14)(15)(16)(17), [11] massadine (18), [12] the styloguanidines (19)(20)(21)(22), [13] the konbuacidins (23 and 24), [14] brominated palauamines (26 and 27), [7b] and the stunning tetrameric stylissadines (28 and 29). [15] Recently, the structure of palauamine was called into question and was revised based on a combination of advanced spectroscopic analysis, computation, and even biosynthetic considerations.…”

Section: Introductionmentioning

confidence: 99%

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The Pursuit of Palau'amine

et al. 2007

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Since its discovery in 1993, the marine natural product palau'amine has intrigued natural product chemists. Its exotic molecular architecture and purported bioactivity made it an ideal target for synthesis. However, as the years went by and related marine alkaloids were isolated, a skeptical eye was cast on the structure of palau'amine; recently these suspicions were confirmed and the structure of palau'amine revised. This Minireview gives a careful overview of the structural revision and its ramifications to both its biogenesis and total synthesis.

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“…To discuss the differences between the old and the new configurations of the palauamines, tetrabromostyloguanidine (22) will be used as a model in the following discussion.…”

Section: Isolation Of the Styloguanidines And Structural Revision Of mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Pursuit of Palau'amine

et al. 2007

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“…Obwohl eine Kopplungskonstante dieser Größenordnung eine cis-Verknüpfung nicht ausschließt, ist eine trans-Verknüpfung viel wahrscheinlicher. [27] [a] Die Berechnungen wurden mit 27 experimentellen ROEs für 1 durchgeführt.…”

Section: Achim Grube Und Matthias Köck*unclassified

Strukturaufklärung des Tetrabromstyloguanidins: Muss die relative Konfiguration der Palau'amine revidiert werden?

Grube

Köck

2007

Angewandte Chemie

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Aus dem karibischen Schwamm Stylissa caribica wurde das Palau'amin‐Derivat Tetrabromstyloguanidin (1) isoliert, dessen Strukturaufklärung mit besonderem Augenmerk auf der relativen Konfiguration beschrieben wird. Ergebnisse aus NMR‐Studien in Kombination mit Molekülstrukturrechnungen machen es wahrscheinlich, dass die Verbindungen der Palau'amin‐Familie eine andere Konfiguration haben, als bisher angenommen wurde.

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“…Thus we further investigated the stereochemistry of the ring junction of the fused 5,5-membered ring of the zirconacycle. 14) When diene 7c was treated with Cp 2 ZrBu 2 and then 10% HCl was added, the two perhydroindole derivatives trans-9c and cis-9c were obtained in a ratio of 2 to 1. Furthermore, treatment of the zirconacycles with carbon monoxide gave the two tricyclic ketones trans-10c and cis-10c in a ratio of 2 to 1.…”

mentioning

confidence: 99%

“…This is the second example of the X-ray crystallography of a trans-fused 5,5-membered ring compound. 14) Chart 5. Formal Total Synthesis of (Ϫ)-Dendrobine …”

mentioning

confidence: 99%

Development of a Novel Synthetic Method for Ring Construction Using Organometallic Complexes and Its Application to the Total Syntheses of Natural Products

Mori

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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Organometallic complexes are useful tools in synthetic organic chemistry. In particular, they play an important role in carbon-carbon bond formation. A metalacycle, i.e., a ring compound containing a transition metal, is a useful intermediate in synthetic organic chemistry. Oxidative cyclization of unsaturated hydrocarbons, such as alkene, alkyne, carbonyl compounds, or nitrile, using a low-valent transition metal is a useful reaction for synthesis of metalacycles. It is known that a metalacycle formed from a late transition metal and unsaturated hydrocarbons is not stable and is easily converted into the reductive elimination product or b-hydrogen elimination product (Eq. 1). Since the low-valent metal complex is regenerated in this reaction, the reaction proceeds with a catalytic amount of the transition metal. On the other hand, the metalacycle formed from an early transition metal and unsaturated hydrocarbons is fairly stable and can be converted into various compounds with functional groups by treatment with various agents (Eq. 2). Therefore a stoichiometric amount of the metal complex is required in this reaction.(1) (2) Negishi et al.2) and Nugent and Calabrese 3) reported the syntheses of zirconacycles 2 from diene, enyne, and diyne 1 using zirconocene (Cp 2 Zr). Hydrolysis of zirconacycle afforded the cyclized compound 3 (Chart 1).Negishi et al. also found a synthetic method of dibutylzirconocene (Cp 2 ZrBu 2 ) from zirconocenedichloride (Cp 2 ZrCl 2 ) and butyl lithium, and dibutylzirconocene is easily converted into zirconocene coordinated by a butene ligand in situ at room temperature 4) (Eq. 3).This was a great discovery in zirconium chemistry because it is difficult to isolate zirconocene with no ligand. We were interested in those results and attempted to form carbon-carbon bonds between the unsaturated hydrocarbons, such as enyne and diene, using zirconocene. Synthesis of Heterocycles Using Zirconium-Mediated Cyclization and Total Synthesis of (؊)-DendrobineThe zirconacycles 2 were easily synthesized in situ from Cp 2 ZrCl 2 and diene, enyne, or diyne 1. To a THF solution of Cp 2 ZrCl 2 and unsaturated hydrocarbon 1 was added BuLi at Ϫ78°C under argon gas, and the solution was stirred at room Organometallic complexes are useful tools in synthetic organic chemistry. We investigated a novel synthetic method for ring construction using organometallic complexes and synthesized natural products and biologically active substances using these methods. Metalacycles formed from an early transition metal and diene, enyne, and diyne are stable under the reaction conditions and they are easily converted into compounds with functional groups by the addition of various agents. We have developed a novel synthetic method of heterocycles from enyne and diene using Cp 2 ZrBu 2 . The total syntheses of (؊)-dendrobine, (؎)-mecembrane, and (؎)-mecembrine were achieved using this procedure. To synthesize these natural products as a chiral form, a novel palladium-catalyzed asymmetric allylic amination was developed, an...

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Syntheses and X-Ray Crystal Structures of Tricyclic Ketones Containing Trans-Fused Azabicyclo[3.3.0]octane Units

Cited by 25 publications

References 2 publications

The Pursuit of Palau'amine

The Pursuit of Palau'amine

Strukturaufklärung des Tetrabromstyloguanidins: Muss die relative Konfiguration der Palau'amine revidiert werden?

Development of a Novel Synthetic Method for Ring Construction Using Organometallic Complexes and Its Application to the Total Syntheses of Natural Products

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