Synthesis of functionalized 3,4-dihydro-2H-pyrans by hetero —Diels-Alder reaction of an enaminoketone with enol ethers

1995 ◽  
Vol 126 (12) ◽  
pp. 1341-1348 ◽  
Author(s):  
K. Bogdanowicz-Szwed ◽  
A. Pałasz
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Enol Ethers ◽  
Diels Alder Reaction

Synthese neuer Pyridin-C-nukleoside der 2 ,3 -Didesoxyribose durch „inverse“ [4+2]-Cycloaddition Synthesis of Novel Pyridine-C-nucleosides of 2,3-Dideoxyribose by „Inverse“ [4+2]-Cycloaddition

1997 ◽  
Vol 52 (7) ◽  
pp. 851-858 ◽  
Author(s):  
Gunther Seitz ◽  
Johanna Siegl
Keyword(s):  
Cycloaddition Reaction ◽  
Alder Reaction ◽  
Diels Alder ◽  
The Novel ◽  
Protecting Group ◽  
Enol Ethers ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Cyclic Ketene Acetals

The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could be deprotected by treatment with 70% trifluoroacetic acid to furnish the free C-nucleosides 10 and 11. The triazine „aglycon“ of 8 contains an electron deficient diazadiene system, highly activated to react with various electron rich dienophiles such as enamines, enol ethers and several cyclic ketene acetals in an „inverse“ [4+2]-cycloaddition reaction. The Diels-Alder adducts spontaneously eliminate N2 and after follow-up reactions the O-TBDPS protected pyridine-C-nucleosides 13, 15, 17,19, 21 and 23 are formed. Removal of the protecting group by treatment with CF3CO2H /H2O leads to the corresponding 2’,3’-dideoxy-β-D-ribofuranosyl- pyridines.

Hetero-Diels–Alder Reaction of Phosphorylated Nitroso Alkenes with Enol Ethers on Water: A Clean Approach Toward 1,2-Oxazine Derivatives

2014 ◽  
Vol 79 (16) ◽  
pp. 7607-7615 ◽  
Author(s):  
Jesús M. de los Santos ◽  
Roberto Ignacio ◽  
Zouhair Es Sbai ◽  
Domitila Aparicio ◽  
Francisco Palacios
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Enol Ethers ◽  
Diels Alder Reaction ◽  
Oxazine Derivatives

scholarly journals Domino reactions in the synthesis of heterocyclic natural products and analogs

2004 ◽  
Vol 76 (11) ◽  
pp. 1967-1983 ◽  
Author(s):  
L. F. Tietze ◽  
N. Rackelmann
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Domino Reactions ◽  
Complex Molecules ◽  
Enol Ethers ◽  
Dicarbonyl Compound ◽  
Bond Forming ◽  
Enantioselective Total Synthesis ◽  
Subsequent Transformation ◽  
Diels Alder Reaction

Domino reactions are defined as processes of two or more bond-forming reactions under identical conditions, in which the subsequent transformation takes place at the functionalities obtained in the former transformation. They allow the efficient synthesis of complex molecules from simple substrates in an ecologically and economically favorable way. A very powerful domino process is the domino Knoevenagel–hetero-Diels–Alder reaction, in which an aldehyde or an beta-ketoester is condensed with a 1,3-dicarbonyl compound or a heteroanalog to give a 1-oxa-1,3-butadiene, which can undergo an inter- or intramolecular hetero-Diels–Alder reaction with dienophiles such as enol ethers or alkenes. The products are dihydropyrans, which can be transformed in a variety of ways. Thus, an extension of the process is the synthesis of highly substituted pyrrolidines, piperidines, and azepanes using aminoaldehydes. The process has also been employed for the enantioselective total synthesis of a variety of alkaloids, such as indol- and ipecacuanha alkaloids. In another domino process, erythrina and homoerythrina alkaloids have been prepared from simple phenylethylamines and ketoesters.

Stereoselective hetero-Diels–Alder reaction of 3-(polyfluoroacyl)chromones with enol ethers. Novel synthesis of 2-RF-containing nicotinic acid derivatives

Tetrahedron ◽  
2008 ◽  
Vol 64 (44) ◽  
pp. 10172-10180 ◽  
Author(s):  
Vyacheslav Ya. Sosnovskikh ◽  
Igor A. Khalymbadzha ◽  
Roman A. Irgashev ◽  
Pavel A. Slepukhin
Keyword(s):  
Nicotinic Acid ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enol Ethers ◽  
Diels Alder Reaction ◽  
Novel Synthesis ◽  
Nicotinic Acid Derivatives
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