Diels−Alder Adducts of 5-Alkynylcyclopentadienols with Tetracyanoethylene and Dimethyl Acetylenedicarboxylate:  An X-ray Crystallographic Study of Unexpected Rearrangement Products

2000 ◽  
Vol 65 (16) ◽  
pp. 4861-4863 ◽  
Author(s):  
James A. Dunn ◽  
Mark Stradiotto ◽  
Michael J. McGlinchey
Keyword(s):  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Crystallographic Study

Einfache Synthese von 2,2-Diethoxy-2,5-dihydrofuranen, 2(5 H)Furanonen und 2-Ethoxy-furanen.Kristall-und Molekülstruktur eines Barrelenon Diels-Aider Produktes [1] / Convenient Synthesis of 2,2-Diethoxy-2,5-dihydrofurans, 2(5 H)Furanones and 2-Ethoxyfurans.Crystal and Molecular Structure of a Barrelenone Diels-Alder Product [1]

1994 ◽  
Vol 49 (3) ◽  
pp. 389-406 ◽  
Author(s):  
Rolf W. Saalfrank ◽  
Wieland Hafner ◽  
Joachim Markmann ◽  
Andreas Welch ◽  
Karl Peters ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Maleic Anhydride ◽  
Structure Analysis ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Reaction Conditions ◽  
X Ray ◽  
Convenient Synthesis

AbstractReaction of 1,2-hydroxyketones 5 with (2,2-diethoxyvinylidene)triphenylphosphorane (2) or (2,2-diethoxyvinyl)triphenylphosphonium tetrafluoroborates 6 yields the 2,2-diethoxy- 2.5-dihydrofurans 9. Depending on the reaction conditions used, the orthoesters 9 can be hydrolized to give 2(5 H)furanones 10 and 2-ethoxyfurans 11, respectively. 4,5-Dimethyl- 5.6-dihydro-2-pyranone (20) and 8-methoxycoumarin (23) are prepared, starting from (2,2-diethoxyvinyl)triphenylphosphonium tetrafluoroborate (6 a) and 1-hydroxy-2-methyl- 3-butanone (16) or 2-hydroxy-3-methoxy-benzaldehyde (21). The 2-ethoxyfuranes 11 readily undergo Diels-Alder reactions with 2-chloracrylonitrile (24), maleic anhydride (26), N-phenyl-1,2,4-triazoline-3,5-dione (28) and dimethyl acetylenedicarboxylate (30) to give the corresponding Diels-Alder products 25, 27, 29 and 31, respectively. Contrary to 2-ethoxyfuran 11b , 11a reacts with two equivalents of acetylene 30, to yield barrelenone 34. The structure of 34 unequivocally is established by X-ray structure analysis.

scholarly journals Two-Carbon Ring Enlargement of Five-, Six-, and Seven-Membered 1-Aza-2-vinylcycloalk-2-enes with Dimethyl Acetylenedicarboxylate and Subsequent Thermal Isomerization Reactions

2006 ◽  
Vol 61 (4) ◽  
pp. 385-395 ◽  
Author(s):  
Gerhard Maas ◽  
Robert Reinhard ◽  
Hans-Georg Herz
Keyword(s):  
Elevated Temperatures ◽  
Alder Reaction ◽  
Thermal Isomerization ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Ring Enlargement ◽  
Diels Alder Reaction ◽  
Carbon Ring ◽  
Electrocyclic Reaction

2-Aminodienes, in which the enamine function is incorporated in a five-, six-, or seven-membered ring, react with dimethyl acetylenedicarboxylate in a sequence of [2+2] cycloaddition and electrocyclic ring-opening to form the two-carbon ring expanded unsaturated heterocycles, i.e., 3,4- dicarboxylate substituted 6,7-dihydro-1H-azepines 3, 8 and 21, 1,6,7,8-tetrahydroazocines 22, and 6,7,8,9-tetrahydro-1H-azonines 13. Similarly, 2-[(2-thienyl)ethynyl]-4,5,6,7-tetrahydro-1H-azepine 9 is converted into 2-[(2-thienyl)ethynyl]-6,7,8,9-1H-azonine-3,4-dicarboxylate 10 which was characterized by X-ray structure determination. The eight- and nine-membered azaheterocycles 22 and 13, which have not been isolated, undergo thermal isomerization at elevated temperatures. Thus, ring contraction by a 6π-electrocyclic reaction takes place for N-methyl substituted azonine 13, while the N-allyl moiety of azocines 22 engages in an intramolecular Diels-Alder reaction or a 1,7- electrocyclization reaction

Diels−Alder Dimerization of Cyclopenta[l]phenanthrene (Dibenz[e,g]indene) with Isodibenzindene:  A Computational, NMR Spectroscopic, and X-ray Crystallographic Study

1998 ◽  
Vol 63 (11) ◽  
pp. 3735-3740 ◽  
Author(s):  
Suzie S. Rigby ◽  
Mark Stradiotto ◽  
Stacey Brydges ◽  
David L. Pole ◽  
Siden Top ◽  
...  
Keyword(s):  
Diels Alder ◽  
X Ray ◽  
Crystallographic Study

Diels-Alder additions of dimethyl acetylenedicarboxylate to sterically hindered cyclohexa-2,4-dienones. Formation and X-ray structure analysis of stereoisomeric bicyclo[2.2.2]octadienones

1983 ◽  
Vol 36 (7) ◽  
pp. 1361 ◽  
Author(s):  
H Becker ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Structure Analysis ◽  
Electronic Absorption ◽  
Spectral Properties ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sterically Hindered

The Diels-Alder addition of dimethyl acetylenedicarboxylate to sterically hindered 2,4-cyclohexadienones (spiro-quinol ethers) gives rise to stereoisomeric bicyclo[2.2.2]octadienones. The structures of three of these have been elucidated by single-crystal X-ray diffraction methods and their 1H n.m.r. and electronic absorption spectral properties are reported.

scholarly journals Diels-Alder Additions to 2,2’-Biaceanthrylene

2021 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Photophysical Properties ◽  
Major Product ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Polycyclic Aromatic ◽  
Single Addition ◽  
Quinone Derivative

A series of Diels-Alder reactions between the diene 2,2’-biaceanthylene and several dienophiles is presented. The diene is a cyclopenta-fused polycyclic aromatic hydrocarbon with anthracene units linked by two cyclopentene rings. Depending on the dienophile, the major product was the result of a single addition (dimethyl acetylenedicarboxylate) or double addition (quinone, benzyne) to the diene. Single crystal X-ray analysis of the quinone-derivative shows a propeller-like structure composed of mixed enantiomers. The synthesis and photophysical properties of these compounds is presented.<br>

Syntheses of Angucyclinones Related to Ochromycinone

1998 ◽  
Vol 51 (6) ◽  
pp. 515 ◽  
Author(s):  
Tomas Rozek ◽  
Wit Janowski ◽  
John M. Hevko ◽  
Edward R. T. Tiekink ◽  
Suresh Dua ◽  
...  
Keyword(s):  
Structural Study ◽  
Alder Reaction ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Diels Alder Reaction ◽  
Synthetic Approaches ◽  
Alder Adduct

Two synthetic approaches have been investigated for the syntheses of model angucyclinones related to ochromycinone. The first involves a Diels–Alder/Friedel–Crafts strategy in which the Diels–Alder adduct formed between dimethyl acetylenedicarboxylate and 3-ethenyl-5,5-dimethylcyclohex-2-en-1- one was converted into 6,6-dimethyl-8-oxo-5,6,7,8-tetrahydronaphthalene-1,2-dicarboxylic anhydride, which was then reacted with benzene in a Friedel–Crafts reaction. Acid-catalysed cyclization of the Friedel–Crafts products gave 3,3-dimethyl-3,4-dihydrobenz[a]anthracene-1,7,12(2H)-trione (3) in poor yield. Angucyclinones related to (3) are formed (in 40–50% overall yield) by aromatization of the adduct formed between the appropriate 1,4-naphthoquinone and 3-[(E)-2-methoxyethenyl]- 5,5-dimethylcyclohex-2-en-1-one (this dienone reacts with itself by a Diels–Alder process to yield an adduct which decomposes to 3,3,8,8-tetramethyl-3,4,7,8-tetrahydroanthracene-1,6(2H,5H)-dione). When the substituted 1,4-naphthoquinone is unsymmetrical, a boron triacetate assisted Diels–Alder reaction gives a single regioisomer (e.g. X-ray investigations indicate that 8-hydroxy-3,3-dimethyl-3,4-dihydrobenz[a]anthracene-1,7,12(2H)-trione is the product from 5-hydroxy-1,4-naphthoquinone). An X-ray structural study of the Diels–Alder adduct in the above reaction confirms the operation of an endo cyclization.

Some 6,6-disubstituted 2,4-cyclohexadien-1-ones and the facial selectivity in their Diels–Alder reactions with dimethyl acetylenedicarboxylate

1989 ◽  
Vol 67 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Peter Yates ◽  
Anabela Gomes ◽  
D. Jean Burnell ◽  
Dong Dao Cong ◽  
Jeffery F. Sawyer
Keyword(s):  
Spectroscopic Method ◽  
Diels Alder ◽  
The Other ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Product Ratio ◽  
X Ray Crystallography ◽  
Facial Selectivity ◽  
Chemical Correlation ◽  
The Individual

6,6-Disubstituted 2,4-cyclohexadien-1-ones can be prepared by dibromination–bisdehydrobromination of the corresponding 6,6-disubstituted 2,2-dibromocyclohexanones. Such dienes undergo Diels–Alder reactions with dimethyl acetylenedicarboxylate to give 3,3-disubstituted 5,6-di(methoxycarbonyl)bicyclo[2.2.2]octa-5,7-dien-2-ones; when the substituents at C-6 in the dienones are different, two diastereomers of the adducts are formed in a ratio dependent on the "facial selectivity" in the Diels–Alder reactions. For the cases where one of the 6-substituents is methyl and the other is methoxycarbonyl, acetoxymethyl, dibromomethyl, or dichloromethyl it has been established via X-ray crystallography and chemical correlation that the endo-3-methyl/exo-3-methyl product ratio is 3.0, 0.9, 8, and 6, respectively. The origin of these differences is discussed briefly and a spectroscopic method for the assignment of structures to the individual diastereomers is proposed. Keywords: Diels–Alderreactions, substituted 2,4-cyclohexadien-1-ones, facial selectivity, dimethyl acetylenedicarboxylate.

Reaction of 2-[(E)-styryl]Quinazolin-4(3H)-one with Acetylenic Esters: Formation of Unexpected N-3 Alkenylation Products

2005 ◽  
Vol 2005 (7) ◽  
pp. 429-431 ◽  
Author(s):  
Tapasi Chatterjee ◽  
Subhagata Chattopadhyay ◽  
Ranjan Mukhopadhyay ◽  
Basudeb Achari ◽  
Santu Chakraborty ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Alder Reaction ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Acetylenic Esters ◽  
X Ray ◽  
Methyl Propiolate ◽  
Diels Alder Reaction ◽  
Centrosymmetric Dimers

Attempted hetero Diels–Alder reaction with 2-[(E)-styryl]quinazolin-4(3H)-one (1) and dimethyl acetylenedicarboxylate (2) resulted in unexpected N-3 alkenylation products, 2-[(E)-styryl]-3-[(Z)-1,2-bis(methoxycarbonyl)vinyl]quinazolin-4(3H)-one (4a) and 3-[(E)-1,2-bis(methoxycarbonyl) vinyl] 2-[(E)-styryl]-quinazolin-4(3H)-one (4b) in low yield. Treating 1 and 2-methylquinazolin-4(3H)-one (9) with methyl propiolate (7) also furnished N-3 alkenylation products in low yield. The structure of 4b has been established by X-ray analysis. The molecules of 4b are linked by intermolecular C-H. … N hydrogen bonds into centrosymmetric dimers forming R22 (12) rings.

π-Facial stereoselectivity in the Diels–Alder reactions of benzene oxides

1991 ◽  
Vol 69 (9) ◽  
pp. 1337-1343 ◽  
Author(s):  
James R. Gillard ◽  
Michael J. Newlands ◽  
John N. Bridson ◽  
D. Jean Burnell
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Steric Hindrance ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Orbital Interactions ◽  
Nuclear Magnetic Resonance Spectra ◽  
Nuclear Overhauser ◽  
Benzene Oxide

The Diels–Alder reactions of N-phenylmaleimide and dimethyl acetylenedicarboxylate with benzene oxide (1,3,5-cyclohexatriene 1,2-oxide, 3) and its more substituted derivatives 1,2-dimethyl-1,3,5-cyclohexatriene 1,2-oxide (7) and 10-oxatricyclo[4.3.1.0]deca-2,4-diene (11) in a kinetic manner gave exclusively products of addition anti to the plane-nonsymmetrical oxygen. The structures of the adducts were determined unequivocally by nuclear Overhauser enhancements in their 1H nuclear magnetic resonance spectra and by X-ray crystallographic methods. The π-facial stereoselectivity was rationalized in terms of unfavorable orbital interactions, steric hindrance between the dienophile and the syn face of benzene oxide, and σ-donation by the oxygen. Key words: cycloaddition, Diels–Alder, syn-anti, π-facial stereoselectivity, benzene oxide.

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