Asymmetric organocatalysis

Seayad, Jayasree; List, Benjamin

doi:10.1039/b415217b

Cited by 1,100 publications

(258 citation statements)

References 121 publications

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“…[1][2][3][4][5][6][7][8][9] Since small chiral organic molecules act as catalytically active species in asymmetric organocatalysis, these organocatalysts are metalfree, usually nontoxic, readily accessible, and often very robust. A significant advantage of many organocatalysts is the capability of multipoint recognition of substrates similar to enzymes.…”

Section: Introductionmentioning

confidence: 99%

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

2010

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We have developed several multifunctional thiourea catalysts bearing a tertiary amine or an 1,2-amino alcohol in expectation of their synchronous activation of a nucleophile and an electrophile through both acid-base and hydrogen-bonding interactions. From these studies, it was revealed that the weak acidity of thioureas compared with metallic Lewis acids could be overcome by this modification. The bifunctional aminothiourea could be used efficiently for a wide range of diastereoselective and enantioselective nucleophilic reactions such as Michael addition of 1,3-dicarbonyl compounds to nitroolefines, aza-Henry reaction of nitroalkanes to N-Boc imines, and hydrazination of cyclic b b-keto esters. We also discovered that multifunctional thiourea catalyst, bearing an 1,2-amino alcohol moiety, significantly accelerated the Petasis-type reaction of alkenylboronic acids to Nphenoxycarbonyl quinolinium salts, prepared from quinolines and phenyl chloroformate, to afford 1,2-addition products with high enantioselectivity (up to 97% ee). Furthermore, to expand the synthetic applicability of the thiourea-catalyzed asymmetric reactions, tandem organocatalyzed reactions were explored to establish the concise one-pot synthesis of chiral densely functionalized three-, five-, and six-membered compounds.

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Section: Introductionmentioning

confidence: 99%

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

2010

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“…22 The discovery that proline catalyzes aldol and related reactions with high enantioselecitivity marked the birth of a new and highly active field of research now known as organocatalysis. 23 Our initial studies of two proline-mediated reactions, the a-aminoxylation 24 and the a-amination 25 of aldehydes, revealed intriguing features including an accelerating reaction rate and asymmetric amplification of product enantiomeric excess. While at first glance these features appear similar to those characterizing the Soai autocatalytic reaction, in fact these amino acid mediated reactions are autoinductive rather than autocatalytic, characterized by involvement of the reaction product in the catalytic cycle.…”

Section: Equilibrium Phase Behavior Model For the Evolution Of Homochmentioning

confidence: 99%

Investigating the evolution of biomolecular homochirality

Blackmond

Klußmann

2006

AIChE Journal

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T he molecular property of chirality has intrigued both scientists and laymen for more than a century and a half. van't Hoff 1 was the first to postulate the existence of chiral molecules-nonsuperimposable forms that are mirror images of one another, as are left and right hands-as early as 1874, a quarter century after Pasteur 2 had shown that salts of tartaric acid exist as mirror image crystals.* Synthesized in the laboratory in the absence of a directing template, the leftand right-handed molecules of a compound, or enantiomers, will form in equal amounts (a ''racemic'' mixture). However, chiral molecules present in nature as part of living organisms are most often produced exclusively in one enantiomeric form. This property of single chirality is critical for molecular recognition and replication processes and would thus seem to be a prerequisite for the origin of life.3 Enantiopure molecules such as enzymes help to direct the synthesis of further enantiopure molecules in living organisms, with prominent examples being the D-sugars and L-amino acids that make up DNA and proteins, respectively. Similar strategies are used in laboratory asymmetric synthesis and catalysis, where we draw upon the natural pool of chiral molecules to provide building blocks for constructing new enantiopure molecules or catalysts. This leads logically to the question: what served as the original templates for biasing production of one enantiomer over the other in the chemically austere, and presumably racemic, environment of the prebiotic soup?This Perspective highlights two models for the evolutionary routes that may have been taken by simple molecules in a racemic prebiotic world to arrive at the high levels of enantiopurity inherent in modern biological molecules. . Soai's landmark discovery 6 of an autocatalytic reaction following these theoretical descriptions, and the subsequent mechanistic studies of the Soai reaction by the groups of Blackmond 7,8 and Brown, 7,9 provide proof of concept for such models. The second model 10,11,12 is an alternative mechanism based on the equilibrium phase behavior of ternary systems of amino acid enantiomers and solvent. Both models focus on identifying means for amplifying a small imbalance in enantiomeric concentrations (''asymmetric amplification''), while the possible origin of this initial imbalance is the subject of other discussions.3 These models offer dramatically different approaches for addressing the fundamental question of how molecular homochirality evolved in the complex molecules required for recognition, replication and ultimately for the chemical basis of life. Autocatalytic Model for the Evolution of HomochiralityMore than sixty years ago, Frank 4 developed a mathematical model for ''spontaneous asymmetric synthesis'', or the autocatalytic production of enantiomerically enriched molecules from a near racemic mixture in the absence of an added chiral template. 13 He showed that a substance that acts as a catalyst in its own self-production, and at the same time acts to suppre...

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“…It was only in 2000, that Benjamin List reported an asymmetric (S)-proline (5) catalysed aldol reaction and officially kicked-off to the "golden age" of Organocatalysis, which is the leading topic of this short review. SOR-CHEM C. Palumbo and M. Guidotti: Organocatalysts for enantioselective synthesis of fine chemicals identified on the mechanistic basis: (i) covalent organocatalysis and (ii) non-covalent organocatalysis [26]. In the former case, within the catalytic cycle, the catalyst covalently binds the substrate, in the latter case only noncovalent interactions, such as hydrogen bonding (H-bonding) or the formation of ion pairs, activate the molecule towards the asymmetric transformation (Figure 4) [27].…”

Section: Definition and Origins Of Organocatalysismentioning

confidence: 99%

Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

Federsel¹

2014

ScienceOpen Research

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Organocatalysis, that is the use of small organic molecules to catalyse organic transformations, has been included among the most successful concepts in asymmetric catalysis and it has been used for the enantioselective construction of C-C, C-N, C-O, C-S, C-P, and C-halide bonds. Since the seminal works in early 2000, the scientific community has been paying an ever-growing attention to the use of organocatalysts for the synthesis, with high yields and remarkable stereoselectivities, of optically active fine chemicals of interest for the pharmaceutical industry. A brief overview is here presented about the two main classes of substrate activation by the catalyst: covalent organocatalysis and non-covalent organocatalysis, with a more stringent focus on some recent outcomes in the field of the latter and of hydrogen-bond-based catalysis. Finally, some successful examples of heterogenisation of organocatalysts are also discussed, in the view of a potential industrial exploitation.

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Asymmetric organocatalysis

Cited by 1,100 publications

References 121 publications

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

Investigating the evolution of biomolecular homochirality

Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

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