Quinone Diels Alder Reactions Research Articles

Enantioselective Redox‐Divergent Chiral Phosphoric Acid Catalyzed Quinone Diels–Alder Reactions

AbstractAn efficient enantioselective construction of tetrahydronaphthalene‐1,4‐diones as well as dihydronaphthalene‐1,4‐diols by a chiral phosphoric acid catalyzed quinone Diels–Alder reaction with dienecarbamates is reported. The nature of the protecting group on the diene is key to the success of achieving high enantioselectivity. The divergent “redox” selectivity is controlled by using an adequate amount of quinones. Reversible redox switching without erosion of enantioselectivity was possible from individual redox isomers.

Enantioselective Redox-Divergent Chiral Phosphoric Acid Catalyzed Quinone Diels-Alder Reactions.

An efficient enantioselective construction of tetrahydronaphthalene-1,4-diones as well as dihydronaphthalene-1,4-diols by a chiral phosphoric acid catalyzed quinone Diels-Alder reaction with dienecarbamates is reported. The nature of the protecting group on the diene is key to the success of achieving high enantioselectivity. The divergent "redox" selectivity is controlled by using an adequate amount of quinones. Reversible redox switching without erosion of enantioselectivity was possible from individual redox isomers.

ChemInform Abstract: Catalytic Asymmetric Diels—Alder Reaction of Quinone Imine Ketals: A Site‐Divergent Approach.

AbstractThe site selectivity in these asymmetric quinone Diels—Alder reactions strongly depends on the structure of the axially chiral dicarboxylic acid catalyst.

Catalytic Asymmetric Diels–Alder Reaction of Quinone Imine Ketals: A Site‐Divergent Approach

AbstractThe catalytic asymmetric Diels–Alder reaction of quinone imine ketals with diene carbamates catalyzed by axially chiral dicarboxylic acids is reported herein. A variety of primary and secondary alkyl‐substituted quinone derivatives which have not been applied in previous asymmetric quinone Diels–Alder reactions could be employed using this method. More importantly, we succeeded in developing a strategy to divert the reaction site in unsymmetrical 3‐alkyl quinone imine ketals from the inherently favored unsubstituted CC bond to the disfavored alkyl‐substituted CC bond.

Catalytic asymmetric diels-alder reaction of quinone imine ketals: a site-divergent approach.

The catalytic asymmetric Diels-Alder reaction of quinone imine ketals with diene carbamates catalyzed by axially chiral dicarboxylic acids is reported herein. A variety of primary and secondary alkyl-substituted quinone derivatives which have not been applied in previous asymmetric quinone Diels-Alder reactions could be employed using this method. More importantly, we succeeded in developing a strategy to divert the reaction site in unsymmetrical 3-alkyl quinone imine ketals from the inherently favored unsubstituted C=C bond to the disfavored alkyl-substituted C=C bond.

ChemInform Abstract: Intramolecular Vinyl Quinone Diels—Alder Reactions: Asymmetric Entry to the Cordiachrome Core and Synthesis of (—)‐Isoglaziovianol.

ChemInform Abstract: Intramolecular Vinyl Quinone Diels—Alder Reactions: Asymmetric Entry to the Cordiachrome Core and Synthesis of (—)‐Isoglaziovianol.

Intramolecular Vinyl Quinone Diels–Alder Reactions: Asymmetric Entry to the Cordiachrome Core and Synthesis of (−)-Isoglaziovianol

A short and asymmetric entry to the core structure of the cordiachromes has been developed, allowing access to (-)-isoglaziovianol in seven steps. Our synthesis includes a Trost asymmetric allylic alkylation and a reaction cascade triggered by a vinyl quinone Diels-Alder reaction and followed by intramolecular nucleophilic interception.

Efficient Total Syntheses of (‐)‐Colombiasin A and (‐)‐Elisapterosin B: Application of the Cr‐Catalyzed Asymmetric Quinone Diels—Alder Reaction.

Efficient Total Syntheses of (‐)‐Colombiasin A and (‐)‐Elisapterosin B: Application of the Cr‐Catalyzed Asymmetric Quinone Diels—Alder Reaction.

Highly Enantio‐ and Regioselective Quinone Diels—Alder Reactions Catalyzed by a Tridentate [(Schiff Base)CrIII] Complex.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Quinone Diels-Alder Reactions Catalyzed by a [(Schiff Base)CrIII] Complex

The quinone Diels-Alder reaction is an important reaction providing precursors to many biologically important compounds. In this paper, the authors report an interesting finding that in catalyst preparation and isolation, the workup procedure is vital for obtaining the appropriately active catalyst for the quinone Diels-Alder reaction. Use of 3 N HCl (not neutral or 1 N HCl) provides the pseudo-octahedral chromium complex that gives high selectivity for the desired reaction. A variety of quinone derivatives and various dienes give consistently high yields, regioselectivity and enantioselectivity showing a very wide scope for this reaction.

Efficient Total Syntheses of (−)‐Colombiasin A and (−)‐Elisapterosin B: Application of the Cr‐Catalyzed Asymmetric Quinone Diels–Alder Reaction

A made-to-order asymmetric catalytic reaction was applied in the key quinone Diels–Alder step of the total syntheses of the title compounds (see scheme for the synthesis of colombiasin A). The reaction was highly regio- and diastereoselective.

Efficient Total Syntheses of (−)‐Colombiasin A and (−)‐Elisapterosin B: Application of the Cr‐Catalyzed Asymmetric Quinone Diels–Alder Reaction

Eine maßgeschneiderte asymmetrische katalytische Reaktion wurde für den zentralen Chinon-Diels-Alder-Schritt in den Totalsynthesen der Titelverbindungen eingesetzt (siehe Schema für die Synthese von Colombiasin A). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2005/z502178_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Highly Enantio‐ and Regioselective Quinone Diels–Alder Reactions Catalyzed by a Tridentate [(Schiff Base)CrIII] Complex

Naturstoffe dienen als Vorbilder für die asymmetrische Katalyse in Syntheseansätzen für Colombiasin A und verwandten komplexen Zielverbindungen. Die Entdeckung hoch selektiver Diels-Alder-Reaktionen von Chinonen mit dem neuen, monomeren Schiff-Base-Chrom(III)-Komplex 1 als Katalysator war ein wichtiger Schritt in dem Unterfangen (siehe Schema; TES=Triethylsilyl, DBU=1,8-Diazabicyclo[5.4.0]undec-7-en).

Highly Enantio‐ and Regioselective Quinone Diels–Alder Reactions Catalyzed by a Tridentate [(Schiff Base)CrIII] Complex

Natural product inspired asymmetric catalysis resulted from an effort directed toward colombiasin A and related complex targets. The discovery of highly selective quinone Diels–Alder reactions catalyzed by the new, monomeric [(Schiff base)CrIII] complex 1 was a requisite step in the synthetic endeavor (see scheme; TES=triethylsilyl, DBU=1,8-diazabicyclo[5.4.0]undec-7-ene). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z502176_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Enantioselective Rare‐Earth Catalyzed Quinone Diels—Alder Reactions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The preparation of forskolin analogs via quinone Diels-Alder reactions

A practical synthetic route for the preparation of compound 2a , a carbocyclic analog of the Δ 5-derivative, 1 , of forskolin has been completed. A quinone Diels-Alder reaction is used for the rapid construction of the tricyclic framework of 2 .

Further Studies on Quinone Diels-Alder Reactions with 1,3,3-Trimethyl-2-vinylcyclohexenes: Regioselective Synthesis of 12-Methyl-podocarpane Diterpenes and Isolation of a Hetero Diels-Alder Product from 1,4-Benzoquinone

Abstract Diels-Alder reactions of 2-[(E)-β-alkoxyvinyl]-1,3,3-trimethyl-cyclohexenes with 2-methoxy-3-methyl-1,4-benzoquinone regioselectively produce adducts possessing the 12-methyl-podocarpane ring skeleton. In addition, in the reaction with 1,4-benzoquinone an unusual hetero Diels-Alder product involving the C[dbnd]O group of the quinone is found in low yield.

Catalysis and regioselectivity of quinone Diels–Alder reactions

In a series of six different cycloadditions of unsymmetrical quinones and alkyl-substituted butadienes, TiCl4 afforded considerable catalysis (–78 °C) and gave regioselectivity identical with that of the thermal reaction (200 °C) and therefore complementary to that BF3 catalysis.