Microwave-specific acceleration of a retro-Diels–Alder reaction

2020 ◽  
Vol 56 (76) ◽  
pp. 11247-11250
Author(s):  
Michael A. Frasso ◽  
Albert E. Stiegman ◽  
Gregory B. Dudley
Keyword(s):  
Microwave Heating ◽  
Alder Reaction ◽  
Thermal Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Selective microwave heating in a viscous solvent accelerates a thermal reaction beyond temperature-based expectations.

Cycloadditionen, XXII [1]. Synthese und thermische Reaktion von S-(Alkyl/Aryl)- 2.3-butadienthiosäure-estern / Cycloadditions, XXII [1]. Synthesis and Thermal Reaction of S-(Alkyl/Aryl)-2,3-butadienethioates

1994 ◽  
Vol 49 (4) ◽  
pp. 542-550 ◽  
Author(s):  
Gerhard Himbert ◽  
Dieter Fink
Keyword(s):  
Alder Reaction ◽  
Thermal Reaction ◽  
Diels Alder ◽  
Alkyl Aryl ◽  
Diels Alder Reaction ◽  
Ester Moiety ◽  
Derivatives Of

While the S-alkyl- or S-phenyl-2,3-butadienethioates 4 a-c are synthesized via the usual “Wittig ylide way”, the corresponding 2-methyl-2,3-butadienethioates 9 a-d and the 2-methyl-4.4-diphenyl-2,3-butadienethioates 9 e,f are obtained by condensation of the allenic acids 7 a,b with the thiols and thiophenols 8 in the presence of dicyclohexylcarbodiimide (DCC) and a catalytic am ount of 4-dimethylaminopyridine (DMAP). In contrast to N- or O-phenyl 2,3- butadienamides or -esters, resp., the phenyl derivatives of 4 and 9 do not undergo the intram olecular Diels-Alder reaction, but by heating, all representatives of 4 only decompose, while 9 a-d and 9 e,f rearrange to 3-alkyl(aryl)thio-2-cyclobuten-1-ones 12a-d and to 3-arylthio- 1-naphthols 14a, b, resp. Heating of the cyclobutenone 12d in the presence of N-methylaniline furnishes the 2-butenanilide 16. On reacting 1-phenylthio-1-propyne 17 with diphenylketene 18, the diphenylacetate 19 is isolated, where the naphthol derivative 14a represents the ester moiety.

Thermal Phenomena Under Microwave Field in the Organic Synthesis Processes: Application to the Diels Alder Reaction

1996 ◽  
Vol 430 ◽  
Author(s):  
R. Saillard ◽  
M. Poux ◽  
M. Audhuy-Peaudecerf
Keyword(s):  
Electric Field ◽  
Microwave Heating ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Thermal Fluctuations ◽  
Alder Reaction ◽  
Diels Alder ◽  
Conventional Heating ◽  
Medium Temperature ◽  
Diels Alder Reaction

AbstractThe influence of the microwave heating on chemical reactions were investigated. The kinetic of the Diels Alder reaction were studied under Microwave irradiation at a frequency of 2.45 GHz in a single mode cavity and were compared to the kinetic obtained by a conventional heating. Experiments were carried out in a liquid solvent in order to have a better control of the medium temperature measurement. In a second part, the presence of a catalytic solid phase was introduced. Some thermal fluctuations which are due to an heterogeneity of the electric field were detected in the medium. They reduce the precision of the results and cause problems of experimental reproducibility. A thermoluminescent material allow a good visualisation of these phenomena.In addition, the profiles of the electric field intensity were modelled by a 2D finite elements method in our reactor in the presence of a solvent. Despite the small size of the sample and the use of a monomode cavity which both limited the heterogeneities of the medium temperature, we showed a great heterogeneity of the electric field intensity and as a result the heterogeneity of the temperature in our sample.In order to avoid these phenomena which induce a lack of reproducibility, a stirring device was developed.The values of the kinetics obtained under the 2 heating modes with the introduction of the stirring device. So, it induces a good control of the medium temperature.All those investigations prompted us to the conclusion that there is no difference between microwave heating and a classical heating in the studied reaction.

Indole synthesis by palladium-catalyzed tandem allylic isomerization – furan Diels–Alder reaction

2017 ◽  
Vol 15 (34) ◽  
pp. 7093-7096 ◽  
Author(s):  
Jie Xu ◽  
Peter Wipf
Keyword(s):  
Microwave Heating ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Palladium Catalyzed ◽  
Indole Synthesis

4-(Furan-2-ylamino)but-2-en-1-yl acetates are converted to substituted indoles under microwave heating in the presence of catalytic tetrakis(triphenylphosphine)palladium(0) and triisopropylphosphite.

The Diels-Alder Reaction of 2-Ethenyl-1,4-Benzodioxin: A New and Simple Synthesis of Bisaryl Ethers

Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 30-32
Author(s):  
Thomas V. Lee ◽  
Alistair J. Leigh ◽  
Christopher B. Chapleo
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Simple Synthesis ◽  
Diels Alder Reaction
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