A general synthesis of the tricyclo[4.4.01,6.05,9]decane (sinularene) and tricyclo[5.4.01,7.06,10]undecane (longifolene) ring systems by selective cleavage of bridged-ring cyclopropyl ketones

Attah-Poku, Samuel K.; Antczak, Kazimierz; Alward, Sandra J.; Fallis, Alex G.

doi:10.1139/v84-295

Cited by 12 publications

(7 citation statements)

References 8 publications

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“…Consistent with our preliminary studies of related cyclopropyl ketones (30), hydrogenolysis of 12 cleaved the least substituted cyclopropane bond exclusively, to release the latent methyl group with concomitant removal of the benzyl function and hydrogenation of the double bond (H,, 10% Pd/C, 85%).…”

Section: Sinularenesupporting

confidence: 83%

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Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

Antczak¹,

Kingston²,

Fallis³

1985

Can. J. Chem.

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Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

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Section: Sinularenesupporting

confidence: 83%

“…With suitably substituted precursors, controlled cleavage of the other cyclopropane bonds should permit entry to the longifolene and sativene series as illustrated (30). Our initial studies revealed (31) that a C5 oxygen substituent was essential to ensure that the desired intramolecular cycloaddition proceeded.…”

Section: Sinularenementioning

confidence: 99%

Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

Antczak¹,

Kingston²,

Fallis³

1985

Can. J. Chem.

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“…In preparation of the cyclopropane ring opening, the TMS ether was cleaved selectively with acetic acid in THF–H 2 O, and the resulting alcohol (single diastereomer after SiO 2 chromatography) was oxidized to provide cyclopropyl ketone 22 . Subsequent cyclopropane ring opening by hydrogenolysis of 22 in glacial acetic acid furnished cis -hydrindanone 23 on gram scale (88% isolated yield, 2.78 g isolated mass) . Notably, the cyclopropane ring opening could also be triggered photochemically by irradiation with UV–C light (λ = 254 nm) in the presence of Et 3 N and LiClO 4 to deliver 23 on a milligram scale (62% isolated yield, 28 mg isolated mass) .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Homoverrucosanoid-Derived Esters and Evaluation as MDR Modulators

et al. 2017

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The synthesis of the A-B-cis,B-C-trans-annulated cyclohepta[e]hydrindane core of a gagunin E analogue is reported in detail. The tricarbocyclic scaffold was assembled starting from an easily accessible A ring building block by a (4 + 2)-cycloaddition for annulation of the B ring. A ring-closing metathesis served for construction of the seven-membered C ring. The angular methyl groups were attached by electrophilic cyclopropanation-ring opening. A library based on the most active lead compound was made accessible by esterification of the terpenols with commercially available acids. A transannular etherification reaction gave access to tetracyclic derivatives of the synthetic inhibitors. The members of the compound library of non-natural homoverrucosanoid-derived esters were examined as modulators of the membrane transporter proteins ABCB1 (P-gp), ABCG2 (BCRP), and ABCC1 (MRP1), which are involved in the formation of multidrug resistance (MDR) in cancer chemotherapy.

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“…An alternative synthetic approach developed by Fallis and co-workers involved blocking the 1,5-hydrogen shift by linking the tether to the cyclopropane moiety in spiro[2.4]heptadiene. , Following the intramolecular cycloaddition, the selective cleavage of the cyclopropane ring shown in Scheme allows access to the tricyclo[4.4.0 1,6 .0 2,8 ]decane or tricyclo[5.4.0 1,7 .0 2,9 ]undecane scaffolds . This approach enabled the synthesis of sinularene in 14 steps and 9% overall yield starting from a spiro[2.4]heptadiene …”

Section: Stability Of Cyclopentadienementioning

confidence: 99%

Click Chemistry with Cyclopentadiene

Levandowski

Raines

2021

Chem. Rev.

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Cyclopentadiene is one of the most reactive dienes in normal electron-demand Diels–Alder reactions. The high reactivities and yields of cyclopentadiene cycloadditions make them ideal as click reactions. In this review, we discuss the history of the cyclopentadiene cycloaddition as well as applications of cyclopentadiene click reactions. Our emphasis is on experimental and theoretical studies on the reactivity and stability of cyclopentadiene and cyclopentadiene derivatives.

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A general synthesis of the tricyclo[4.4.0^1,6.0^5,9]decane (sinularene) and tricyclo[5.4.0^1,7.0^6,10]undecane (longifolene) ring systems by selective cleavage of bridged-ring cyclopropyl ketones

Cited by 12 publications

References 8 publications

Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

Synthesis of Homoverrucosanoid-Derived Esters and Evaluation as MDR Modulators

Click Chemistry with Cyclopentadiene

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