Cycloheptatriene Norcaradiene Equilibrium in Dimethyl trans-3,8-Dihydroheptalene-3,8-dicarboxylate

1993 ◽  
Vol 46 (10) ◽  
pp. 1613 ◽  
Author(s):  
A Menzek ◽  
M Balci
Keyword(s):  
Maleic Anhydride ◽  
Singlet Oxygen ◽  
Dimethyl Fumarate ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Catalysed Reaction ◽  
Diethyl Azodicarboxylate

Diels-Alder cycloadditions of dienophiles , such as 4-phenyl-1,2,4-triazoline-3,5-dione, dimethyl acetylenedicarboxylate, dimethyl fumarate , diethyl azodicarboxylate , maleic anhydride, benzyne and p-benzoquinone, to dimethyl trans-3,8-dihydrohexalene-3,8-dicarboxylate (4) have been investigated, and monoaddition products (9)-(16) have been isolated. It has been shown that a second addition to this system occurs only with singlet oxygen and with benzyne. Furthermore, it has been established that the second addition is retarded because of the strain in the cycloheptatriene molecule. The anti bicyclic endoperoxides (21)-(25) formed have been converted, either on heating or in a Co( tpp )- catalysed reaction, into the corresponding bisepoxides (27)-(31).

Vinylindenes and Some Heteroanalogs in the Diels-Alder Reaction. X. Dibenzofurans From 3-Vinylbenzofurans

1991 ◽  
Vol 44 (8) ◽  
pp. 1085 ◽  
Author(s):  
JR Pearson ◽  
QN Porter
Keyword(s):  
Maleic Anhydride ◽  
Alder Reaction ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Diels Alder Reaction

3-Vinylbenzofuran, 3-isopropenylbenzofuran and 2-methyl-3-vinylbenzofuran give normal [4π+2π] adducts with ethenetetracarbonitrile, accompanied, in the case of the last named diene, by the isomeric cyclobutane. Normal adducts also result from these dienes and 4-phenyl-1,2,4-triazoline-3,5-dione, and from 3-vinylbenzofuran and both maleic anhydride and N- phenylmaleimide. 3-Vinylbenzofuran gives the rearranged adduct dimethyl 1,2-dihydrodibenzofuran-3,4-dicarboxylate with dimethyl acetylenedicarboxylate.

Vinylindenes and some heteroanalogues in the Diels-Alder reaction. II. Substituted fluorenes from 3-vinylindenes

1977 ◽  
Vol 30 (5) ◽  
pp. 1061 ◽  
Author(s):  
R Bergamasco ◽  
QN Porter
Keyword(s):  
Mass Spectrometry ◽  
Maleic Anhydride ◽  
Alder Reaction ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Diels Alder Reaction

3-Vinylindene, 2-methyl-3-vinylindene and 3-isopropenylindene give normal, photostable adducts with ethenetetracarbonitrile by a Diels- Alder process. The first diene gives adducts with maleic anhydride, N- phenylmaleimide and dimethyl acetylenedicarboxylate. Where there is stereochemical ambiguity the adducts are shown by mass spectrometry to be exclusively endo. Two heterocyclic analogues are formed from 3- vinylindene with p-toluenesulphonyl cyanide and N-sulphinyl-p- toluenesulphonamide.

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.

Diastereoselectivity and asymmetric induction in the Diels–Alder reaction of o-quinodimethanes

1986 ◽  
Vol 64 (4) ◽  
pp. 720-725 ◽  
Author(s):  
James L. Charlton
Keyword(s):  
Maleic Anhydride ◽  
Methyl Acrylate ◽  
Dimethyl Fumarate ◽  
Alder Reaction ◽  
Diels Alder ◽  
Asymmetric Induction ◽  
Diels Alder Reaction ◽  
The Absolute ◽  
Alkoxy Groups

The extent of asymmetric induction in the bimolecular Diels–Alder reactions of chiral o-quinodimethanes with dimethyl fumarate, methyl acrylate, and maleic anhydride has been studied. o-Quinodimethanes with chiral α-alkoxy groups were prepared from 1-alkoxy-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4a–f or 1-alkoxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4g–h by thermolysis. These alkoxybenzosulfones were prepared from the corresponding hydroxybenzosulfones 8 and 1-phenylethanol, 2-phenyl-1-propanol, 4-phenyl-2-butanol, 1-phenyl-2-propanol, 3,3-dimethyl-2-butanol, or 1-cyclo-hexylethanol. The 1-phenylethoxy substituent yielded the largest asymmetric induction. The absolute configurations of the major cycloadducts of methyl acrylate with the o-quinodimethanes generated from 1-(R- 1-phenylethoxy)- and 1-(S-1-phenylethoxy)-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4i and 4j have been determined to be 1S,2S-1-(R-1-phenylethoxy)- and 1R,2R-1-(S-1-phenylethoxy)-2-carbomethoxy-1,2,3,4-tetrahydronaphthalene 11i and 11j, respectively. The proposition that a chiral alkoxy substituent can block one face of the o-quinodimethane towards addition of a dienophile is discussed.

The Cycloaddition Reactions of Some 7-Alkylidenecycloocta-1,3,5-trienes

1990 ◽  
Vol 43 (3) ◽  
pp. 463 ◽  
Author(s):  
PH Ferber ◽  
GE Gream ◽  
PK Kirkbride ◽  
ERT Tiekink
Keyword(s):  
Maleic Anhydride ◽  
Cycloaddition Reactions ◽  
Dimethyl Acetylenedicarboxylate ◽  
Chlorosulfonyl Isocyanate ◽  
Diethyl Azodicarboxylate

A number of 7-alkylidenecycloocta-1,3,5-trienes, all unstable, yield novel π8+π2 cycloadducts with a range of π2-addends. The reactions of 7-methylenecycloocta-1,3,5-triene with ethene-tetracarbonitrile, 4- phenyl-1,2,4-triazoline-3,5-dione, diethyl azodicarboxylate and chlorosulfonyl isocyanate are described. The tetraene did not react with maleic anhydride or dimethyl acetylenedicarboxylate. As well, the reactions of 1,3,5-trimethyl-7-methylenecycloocta-1,3,5-triene, 2,9a- dihydro-1H-cyclopentacyclooctene and 1,2,3,10a- tetrahydrobenzocyclooctene with ethenetetracarbonitrile and of 7- isopropylidenecycloocta-1,3,5-triene with 4-phenyl-1,2,4-triazoline- 3,5-dione are discussed. The intermediacy of homotropylium zwitterions in the reactions is postulated.

E,E- and E,Z-α-phenyl-α′-acetoxyorthoquinodimethane: steric and electronic control of cycloaddition reactions

1986 ◽  
Vol 64 (4) ◽  
pp. 793-798 ◽  
Author(s):  
James L. Charlton ◽  
Mian M. Alauddin ◽  
Glenn H. Penner
Keyword(s):  
Maleic Anhydride ◽  
Electronic Properties ◽  
Dimethyl Fumarate ◽  
Diels Alder ◽  
Addition Reactions ◽  
Cycloaddition Reactions ◽  
Electronic Control ◽  
Dimethyl Maleate ◽  
Cis And Trans ◽  
Abinitio Calculations

E,E- and E,Z-α-phenyl-α′-acetoxyorthoquinodimethanes have been prepared from the corresponding cis- and trans-1-acetoxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxides. The regio- and diastereoselectivity of the addition reactions with dimethyl fumarate, dimethyl maleate, maleic anhydride, and methyl crotonate have been determined. Abinitio calculations have been carried out on orthoquinodimethane and its α-phenyl and α-oxy derivatives. A correlation has been made between the steric and electronic properties of the orthoquinodimethanes and the regio- and diastereoselectivity of their Diels–Alder reactions.

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