An Unusual Domino Claisen−Conia Reaction Producing 3,5-Dispirodihydrofuran-2,4-diones

Schobert, Rainer; Siegfried, Sven; Gordon, G. J.; Nieuwenhuyzen, Mark; Allenmark, Stig

doi:10.1002/1099-0690(200105)2001:10<1951::aid-ejoc1951>3.0.co;2-y

Cited by 20 publications

(5 citation statements)

References 24 publications

(2 reference statements)

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“…A tandem Claisen-Conia rearrangement was developed for the synthesis of dispirolactones by heating 5-spirotetronates in toluene in a sealed tube (Scheme 146). 169 The first step in the synthesis consisted of a Claisen rearrangement to produce the corresponding 3-allyltetronic acids, which suffered a fast Conia oxaene reaction leading to the 3-spirocyclopropyl ring closing, whose stereoselectivity could be understood in terms of the orbital interactions between the enol HOMO and the alkene LUMO.…”

Section: Heterocyclic Compoundsmentioning

confidence: 99%

Claisen Rearrangement over the Past Nine Decades

2004

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Section: Heterocyclic Compoundsmentioning

confidence: 99%

Claisen Rearrangement over the Past Nine Decades

2004

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“…1 35 or the sponge-produced cytotoxic melophlins. 36 In the case of allyl esters, further pericyclic reactions may follow the cyclization step, depending on the temperature and solvent polarity. 37 For example, one-pot reaction of methallyl (S)-lactate (4) and 3 in toluene under microwave irradiation (sealed vial, 180°C, 10 min) afforded the 3-(but-2-enyl)-5-methyltetronic acid 5 in 65% yield.…”

Section: -And 34-functionalized Systemsmentioning

confidence: 99%

Phosphorus Ylide Based Functionalizations of Tetronic and Tetramic Acids

Schobert¹,

Dietrich²,

Mullen³

et al. 2006

Synthesis

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The versatility of the ylide (triphenylphosphoranylidene)ketene (Ph 3 P=C=C=O, 3) in the construction of tetronic and tetramic acids from various carboxylic acid derivatives is demonstrated by new reactions and extensions of known ones. With a-hydroxy or a-amino esters, 3 affords tetronates or tetramates. A twostep synthesis of (-)-epi-blastmycinolactol shows that allyl a-hydroxy esters can be domino Wittig-Claisen reacted to give 3-allyltetronic acids. More extended Wittig-Claisen-Conia cascades can produce 3-alkylidenefuran-2,4-diones, the photooxygenation of which furnishes lactone endoperoxides with antiplasmodial potential. Tetronic acids can be acylated by 3 at C3 to give the corresponding acyl ylides. Their saponification yields the respective 3acetyl compounds, e.g. the fungal metabolite pesthetoxin. a-Hydroxy acids react with 3 to afford the corresponding 3-phosphoranylidenefuran-2,4-diones. The antibiotic (R)-reutericyclin was built up from benzyl D-leucinate and 3 in four steps by downstream acylation first at C3, then at N1 without racemization.

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“…The proposed spirocyclopropane intermediate was supported by the isolation of spirocyclopropane 5 as shown in eq 4 …”

Section: Resultsmentioning

confidence: 91%

Asymmetric Formal Abnormal Claisen Rearrangement Enabled by Rh-Catalyzed Regio- and Enantioselective Allylic Alkylation

Liu

Xia

et al. 2023

ACS Catal.

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Abnormal Claisen rearrangement of phenyl allyl ether with the γ-alkyl group is longstanding. However, the asymmetric version of this named reaction has never been reported. Herein, a highly regio-and enantioselective allylic alkylation of 4-hydroxycoumarin and stereospecific Conia-ene/ene sequence has been developed as a formal abnormal Claisen rearrangement. Chiral 4-hydroxycoumarins with 3-allyl groups could be synthesized in up to 95% yield and 96% ee under the catalysis of Rh and chiral bioxazolinephosphine ligand. Experimental and density functional theory calculation investigations support that the stereospecific rearrangement is based on the reversible formation of the kinetically favored cis-disubstituted spirocyclopropane intermediate.

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An Unusual Domino Claisen−Conia Reaction Producing 3,5-Dispirodihydrofuran-2,4-diones

Cited by 20 publications

References 24 publications

Claisen Rearrangement over the Past Nine Decades

Claisen Rearrangement over the Past Nine Decades

Phosphorus Ylide Based Functionalizations of Tetronic and Tetramic Acids

Asymmetric Formal Abnormal Claisen Rearrangement Enabled by Rh-Catalyzed Regio- and Enantioselective Allylic Alkylation

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