Journal ArticleDOI
Organocatalytic Sequential One-Pot Double Cascade Asymmetric Synthesis of Wieland−Miescher Ketone Analogues from a Knoevenagel/Hydrogenation/Robinson Annulation Sequence: Scope and Applications of Organocatalytic Biomimetic Reductions
TLDR
First time, for the first time, the one-step alkylation of dimedone and 1,3-cyclohexanedione with aldehydes and Hantzsch ester is developed through an organocatalytic reductiveAlkylation strategy.Abstract:
A practical and novel organocatalytic chemo- and enantioselective process for the cascade synthesis of highly substituted 2-alkyl-cyclohexane-1,3-diones and Wieland−Miescher (W−M) ketone analogs is presented via reductive alkylation as a key step. First time, we developed the one-step alkylation of dimedone and 1,3-cyclohexanedione with aldehydes and Hantzsch ester through an organocatalytic reductive alkylation strategy. Direct combination of l-proline-catalyzed cascade Knoevenagel/hydrogenation and cascade Robinson annulation of CH acids (dimedone and 1,3-cyclohexanedione), aldehydes, Hantzsch ester, and methyl vinyl ketone furnished the highly functionalized W−M ketone analogues in good to high yields and with excellent enantioselectivities. Many of the reductive alkylation products show a direct application in pharmaceutical chemistry.read more
Citations
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Journal ArticleDOI
Asymmetric Organocatalysis: From Infancy to Adolescence
TL;DR: This Review deals with selected studies reported in 2006 and the first half of 2007, and is intended to highlight four main aspects that may be taken as testimony of the present status and prospective of organocatalysis.
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Catalytic C-C bond-forming multi-component cascade or domino reactions: pushing the boundaries of complexity in asymmetric organocatalysis.
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Asymmetric Organocatalytic Cyclization and Cycloaddition Reactions
Albert Moyano,Ramon Rios +1 more
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Transfer hydrogenation with Hantzsch esters and related organic hydride donors
Chao Zheng,Shu-Li You +1 more
TL;DR: In this critical review, recent advances in this area are summarized and classified according to unsaturated functional groups being reduced and catalytic systems employed.
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Asymmetrische Organokatalyse: Eintritt in die Reifezeit†
TL;DR: In this article, the Forschungen auf diesem Gebiet nun in einem Stadium angelangt, in dem speziellere Aufgabenstellungen und insbesondere auch stereochemische Probleme gezielt angegangen werden konnen.
References
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Amino Acid Catalyzed Direct Asymmetric Aldol Reactions: A Bioorganic Approach to Catalytic Asymmetric Carbon-Carbon Bond-Forming Reactions
TL;DR: Direct asymmetric catalytic aldol reactions have been successfully performed using aldehydes and unmodified ketones together with commercially available chiral cyclic secondary amines as catalysts and the observed stereochemistry of the products is in accordance with the proposed transition state.
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New Type of Asymmetric Cyclization to Optically Active Steroid CD Partial Structures
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A General Organocatalyst for Direct α-Functionalization of Aldehydes: Stereoselective C−C, C−N, C−F, C−Br, and C−S Bond-Forming Reactions. Scope and Mechanistic Insights
Johan Franzén,Mauro Marigo,Doris Fielenbach,Tobias C. Wabnitz,and Anne Kjærsgaard,Karl Anker Jørgensen +5 more
TL;DR: The development of a general organocatalyst for the alpha-functionalization of aldehydes, via an enamine intermediate, is presented and mechanistic insight into the reaction course applying nonlinear effect studies, kinetic resolution, and computational investigations leading to an understanding of the properties of the alpha,alpha-diarylprolinol silyl ether catalysts.
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Catalytic Asymmetric Synthesis of anti-1,2-Diols
Benjamin List,Wolfgang Notz +1 more
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Quantum mechanical predictions of the stereoselectivities of proline-catalyzed asymmetric intermolecular aldol reactions.
TL;DR: Experimental tests of quantum mechanical predictions of the ratio of four stereoisomeric products expected from two complex reactions involving the aldol reactions of cyclohexanone with benzaldehyde or with isobutyraldehyde catalyzed by (S)-proline provide an assessment of the state of the art in quantum mechanical prediction of products of complex organic reactions in solution.