Biomimetic Diels−Alder Cyclizations for the Construction of the Brevianamide, Paraherquamide Sclerotamide, and VM55599 Ring Systems

1998 ◽  
Vol 120 (5) ◽  
pp. 1090-1091 ◽  
Author(s):  
Robert M. Williams ◽  
Juan F. Sanz-Cervera ◽  
Félix Sancenón ◽  
J. Alberto Marco ◽  
Kathleen Halligan
Keyword(s):  
Diels Alder ◽  
Ring Systems

scholarly journals One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes

2010 ◽  
Vol 6 ◽  
Author(s):  
Priyabrata Roy ◽  
Binay Krishna Ghorai
Keyword(s):  
Diels Alder ◽  
Fischer Carbene Complexes ◽  
One Pot ◽  
Carbene Complexes ◽  
Ring Systems ◽  
First Report ◽  
Fischer Carbene ◽  
Carbonyl Derivatives ◽  
Transient Intermediates ◽  
Three Component Coupling

One-pot three-component coupling ofo-alkynylheteroaryl carbonyl derivatives with Fischer carbene complexes and dienophiles leading to the synthesis of quinoxaline and phenazine ring systems has been investigated. This involves the generation of furo[3,4-b]pyrazine and furo[3,4-b]quinoxaline as transient intermediates, which were trapped with Diels–Alder dienophiles. This is the first report on furo[3,4-b]pyrazine intermediates.

Solution photochemistry. XII. Novel tricyclic ring systems from the photolysis of diels-alder adducts

1973 ◽  
Vol 14 (30) ◽  
pp. 2871-2874 ◽  
Author(s):  
John R. Scheffer ◽  
James Trotter ◽  
Rudolf E. Gayler ◽  
Cedric A. Bear
Keyword(s):  
Diels Alder ◽  
Ring Systems

Part 2: Efficient strategies for the construction of variably substituted bicyclo[5.3.1]undecenones (AB-taxane ring systems) and their conversion to tricyclo[9.3.1.03,8]pentadecenones (ABC taxane ring systems) and bicyclo[2.2.2]octanones

2004 ◽  
Vol 82 (2) ◽  
pp. 227-239 ◽  
Author(s):  
Nidia P Villalva-Servín ◽  
Alain Laurent ◽  
Alex G Fallis
Keyword(s):  
Lewis Acid ◽  
Sigmatropic Rearrangement ◽  
Diels Alder ◽  
Direct Access ◽  
Cope Rearrangement ◽  
Ring Closing Metathesis ◽  
Ring Systems ◽  
Sigmatropic Rearrangements ◽  
Key Words Magnesium ◽  
Cope Rearrangements

The extension of our strategies for the construction of cyclic molecules containing variably substituted bicyclo[5.3.1]undecenones (AB taxane ring systems) for the synthesis of the tricyclo[9.3.1.03,8]pentadecenone (ABC taxane ring system) and bicyclo[2.2.2]octanones are described. These routes employ a multi-component coupling protocol that employs sequential magnesium-mediated carbometallation of allyl-substituted propargyl alcohols followed by diastereoselective Lewis acid catalyzed intramolecular Diels–Alder reactions (IMDA). Subsequent ring-closing metathesis (RCM) afforded the ABC taxane core structure. Enone accelerated [3,3] sigmatropic rearrangements (Cope rearrangements) generated the bicyclo[2.2.2]octanone nucleus. In the presence of a Lewis acid, the dienophile precursor underwent a tandem reaction via the adduct directly to the bicyclo[2.2.2]octanones. This is the first example of a novel enone accelerated carbocycle Cope rearrangement and provides direct access to bicyclo[2.2.2]octanones by a new route that compliments the traditional cyclohexadiene cycloaddition approach. Key words: magnesium chelate, Lewis acid, taxanes, Diels–Alder, sigmatropic rearrangement, oxy-Cope, ring-closing metathesis, bicyclo[2.2.2]octanone.

Intramolecular Diels−Alder Reactions of 3-(Tetrahydropyridinyl)indoles:  Stereoselective Synthesis of Novel Pentacyclic Ring Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 1974-1980 ◽  
Author(s):  
Parviz Gharagozloo ◽  
Masao Miyauchi ◽  
Berry Birdsall ◽  
Nigel J. M. Birdsall
Keyword(s):  
Stereoselective Synthesis ◽  
Diels Alder ◽  
Ring Systems

Intramolecular Diels-Alder Additions of Benzynes to Furans. Exploratory Studies

1986 ◽  
Vol 39 (4) ◽  
pp. 635 ◽  
Author(s):  
WM Best ◽  
D Wege
Keyword(s):  
Carboxylic Acid ◽  
Carbon Atom ◽  
Anthranilic Acid ◽  
Furan Ring ◽  
Alkoxy Group ◽  
Diels Alder ◽  
Ring Systems ◽  
Terminal Carbon Atom ◽  
Furan Moiety

A series of 3-alkoxyanthranilic acids, in which a furan ring is attached to the terminal carbon atom of the alkoxy group, has been prepared. When the chain linking the anthranilic acid and furan ring systems is three or four atoms long, decomposition of the derived diazonium chlorides generates the corresponding benzynes , which are efficiently trapped intramolecularly by the furan moiety. Diazotization of 2-amino-3-furfuryloxybenzoic acid, where the linking chain is two atoms long, results in fragmentation with the formation of 6-diazo-5- oxocyclohexa-1,3-diene-1-carboxylic acid.

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