Enolether, XVII. Die Acylierung von (Trimethylsilyl)enolethern mit Malonyldichlorid — Darstellung von 4‐Hydroxy‐2<i>H</i>‐pyran‐2‐onen

Effenberger, Franz; Ziegler, Thomas; Schönwälder, Karl-Heinz; Kesmarszky, Thomas; Bauer, Bernd

doi:10.1002/cber.19861191116

Cited by 26 publications

(8 citation statements)

References 13 publications

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“…Un- fortunately, all attempts so far to react bisketene acetal 13 under various conditions (e.g. Lewis acid catalyzed, [13] pressure 13 kbar [14] ) with pyrone 18 [15] and with more electrondeficient pyrones like 19, [16] 20, [17] and 21 [18] did not lead to the expected Diels ± Alder adduct 17.…”

Section: Resultsmentioning

confidence: 99%

Studies towards Trichodimerol: Novel Cascade Reactions and Polycyclic Frameworks

et al. 1999

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Trichodimerol (1) is a synthetically attractive natural product because of its potential medical use against septic shock and its striking molecular architecture. We report herein the possible biosynthetic pathway for its formation from the hexaketide sorbicillin (3) and our preliminary results towards the total synthesis of trichodimerol (1) and its congener demethyltrichodimerol (2). These studies provided a way to synthesize b-ketal ketones by a novel variation of the Mukaiyama Aldol reaction, afforded new insight into the mild and regioselective formation of silyl enol ethers, and allowed the preparation of the advanced intermediate 38.Furthermore, a number of unprecedented cascade reactions were discovered furnishing novel polycyclic, highly oxygenated compounds from simple starting materials.

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Section: Resultsmentioning

confidence: 99%

Studies towards Trichodimerol: Novel Cascade Reactions and Polycyclic Frameworks

et al. 1999

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“…m e structure was Confirmed by comparison wrth publlshed data 15. m e structure was Confirmed by comparison wrth publlshed data 15.…”

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confidence: 89%

Novel Reactions of Carbon Suboxide. IX. Synthesis of 2H-Pyran-2-one Derivatives

Bonsignore¹,

Cabiddu²,

Loy³

et al. 1989

HETEROCYCLES

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unlverslt& vla ospedale 72, 09124 Cagllarl, Italy b~~t l t~t~ dl chlmlca Organlca, unlverslth, vla Ospedale 72, 09124 cagilarl, ~t a l y Abstract -Trlmethylsilyl enol etners of aldehydes and acycilc or cyclic Ketones react wltn carbon suboxlde to glve substltuted 4-[(trlmethylsllylloxyl-2H-pyran-2-ones in good ylelds, wnlch were treated with water to afford the corresponding 4-nydroxy-2~pyran-?-ones It 1s already known tnat a-pyronlc derlvatlves are an Important class of neterocycllc compounds present in a large number of natural substances Recently, Received, 19th December, 1 9 8 8

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“…zu entnehmen. 7 ( 2 ) C ( 3 ) -C ( 4 ) 111.1 ( 2 ) C ( 3 ) -C ( 3 1 ) 1 5 5 . 5 ( 2 ) C ( 2 ) -0( 1) -C ( 6 ) 1 2 1 .…”

Section: -Cyclohexyl-34-dioxo-2h5h-pyrano(l3-~]p~ran-5-on (29d)unclassified

Enolate, II. Einfache Synthese von 3,4‐Dihydro‐2,4‐dioxo‐2H‐pyranen und 2‐Pyronen Enolate als 1,3‐Dianion‐Äquivalente Kristall‐ und Molekülstruktur von 6‐Ethoxy‐3,4‐dihydro‐3,3‐dimethyl‐2,4‐ dioxo‐2H‐pyran‐5‐carbonsaure‐ethylester

et al. 1990

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Enolate Ions, I1 I). -Convenient Synthesis of 3.4-Dihydr0-2.4-dioxo-2H-pyrans and 2-Pyrones. -Enolate Ions as Synthetic Equivalents of 1.3-Dianions. -Crystal and Molecular Structure of Ethyl 6-Ethoxy-3,4-dihydro-3,3-dimethyl-2,4-dioxo- 2H-pyran-5-carboxylateReaction of dimethylmalonyl chloride (Sa) or cyclic 1,l-dicarbony1 dichlorides 6 b -d with two eqivalents of lithium enolates 7, 22, and silyl enol ethers 8, respectively, yields 3,4-dihydro-2,4-dioxo-2H-pyrans 10, 24, or spiro compounds 11 -13,25-27. The spiro[2S]octenes 11 and 25 isomerize spontaneously to give 2-pyrones 14, 28, whereas spiro[3S]nonenes 12,26 rearrange only on heating in the presence of aluminium trichloride to form the corresponding 2-pyrones 15 and 29.However, 10,13 as well as 24,27 do not isomerize under these conditions. Reaction of dicarbonyl dichlorides 6a, c with one equivalent of ketene acetall6 leads to hydroxy-dioxo-2H-pyrans 17a, c. On the contrary, treatment of tetraethoxyallene (18) with dicarbonyl dichlorides 6a, b leads to dihydro-2,4-dioxo-2H-pyran 19a (X-ray structure analysis) and spiro (Trimethylsily1)enolether von Aldehyden und acyclischen oder cyclischen Ketonen4), Ketoenolether'), Acetessigester6) und die Thallium(1)-Sake von tert-Butylacetessigester" reagieren bei der Acylierung mit Malonyldichlorid unter RingschluB zu 2H-Pyran-2-onen *I. Im folgenden berichten wir uber eine einfache Methode zur Darstellung von 2H-Pyran-2-onen mit breit gefachertem Substitutionsmuster. Da 2H-Pyran-Zone in der Natur weit verbreitet sind und zudem 1 entwickelten Konzept hat sich gezeigt, daD auch die Eno-

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Enolether, XVII. Die Acylierung von (Trimethylsilyl)enolethern mit Malonyldichlorid — Darstellung von 4‐Hydroxy‐2H‐pyran‐2‐onen

Cited by 26 publications

References 13 publications

Studies towards Trichodimerol: Novel Cascade Reactions and Polycyclic Frameworks

Studies towards Trichodimerol: Novel Cascade Reactions and Polycyclic Frameworks

Novel Reactions of Carbon Suboxide. IX. Synthesis of 2H-Pyran-2-one Derivatives

Enolate, II. Einfache Synthese von 3,4‐Dihydro‐2,4‐dioxo‐2H‐pyranen und 2‐Pyronen Enolate als 1,3‐Dianion‐Äquivalente Kristall‐ und Molekülstruktur von 6‐Ethoxy‐3,4‐dihydro‐3,3‐dimethyl‐2,4‐ dioxo‐2H‐pyran‐5‐carbonsaure‐ethylester

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