Artificial holoenzymes for benzoin condensation using thiazolio-appended β-cyclodextrin dimers

Ikeda, Hiroshi; Horimoto, Yasuhide; Nakata, Machiko; Ueno, Akihiko

doi:10.1016/s0040-4039(00)01082-0

Cited by 25 publications

(10 citation statements)

References 8 publications

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“…4). All three compounds catalyzed the benzoin condensation with 20 being 4 fold better than 19 and 21 and 26 fold better than a simple thiazolium salt (30).…”

Section: Cyclodextrins With Other Heterocyclic Groupsmentioning

confidence: 97%

Cyclodextrin derivatives that display Enzyme Catalysis

Marinescu

Bols

2009

TIGG

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“…4). All three compounds catalyzed the benzoin condensation with 20 being 4 fold better than 19 and 21 and 26 fold better than a simple thiazolium salt (30).…”

Section: Cyclodextrins With Other Heterocyclic Groupsmentioning

confidence: 97%

Cyclodextrin derivatives that display Enzyme Catalysis

Marinescu

Bols

2009

TIGG

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“…This is explained by invoking that two benzaldehyde molecules can reside simultaneously in the hydrophobic interior of γ-cyclodextrin. Analogues of 86 made of β-cyclodextrin (cyclomaltoheptaose) do not catalyze the benzoin condensation as well [334,335]. In the presence of secondary amines such as piperidine and morpholine, which combine with benzaldehyde to give iminium ion intermediates, modest yields of α-aminoketones (PhCOCH(NR 2 )Ph) have been obtained in boiling EtOH in the presence of 3-methylthiazolium tetrafluoroborate and Et 3 N [329].…”

Section: Benzoin Condensation: Umpolung Of Aldehydesmentioning

confidence: 99%

“…Analogues of 86 made of β-cyclodextrin (cyclomaltoheptaose) do not catalyze the benzoin condensation as well [334,335].…”

Section: An Intermediate Carbanionmentioning

confidence: 99%

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Organocatalysis: Fundamentals and Comparisons to Metal and Enzyme Catalysis

et al. 2016

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Catalysis fulfills the promise that high-yielding chemical transformations will require little energy and produce no toxic waste. This message is carried by the study of the evolution of molecular catalysis of some of the most important reactions in organic chemistry. After reviewing the conceptual underpinnings of catalysis, we discuss the applications of different catalysts according to the mechanism of the reactions that they catalyze, including acyl group transfers, nucleophilic additions and substitutions, and C-C bond forming reactions that employ umpolung by nucleophilic additions to C=O and C=C double bonds. We highlight the utility of a broad range of organocatalysts other than compounds based on proline, the cinchona alkaloids and binaphthyls, which have been abundantly reviewed elsewhere. The focus is on organocatalysts, although a few examples employing metal complexes and enzymes are also included due to their significance. Classical Brønsted acids have evolved into electrophilic hands, the fingers of which are hydrogen donors (like enzymes) or other electrophilic moieties. Classical Lewis base catalysts have evolved into tridimensional, chiral nucleophiles that are N-(e.g., tertiary amines), P-(e.g., tertiary phosphines) and C-nucleophiles (e.g., N-heterocyclic carbenes). Many efficient organocatalysts bear electrophilic and nucleophilic moieties that interact simultaneously or not with both the electrophilic and nucleophilic reactants. A detailed understanding of the reaction mechanisms permits the design of better catalysts. Their construction represents a molecular science in itself, suggesting that sooner or later chemists will not only imitate Nature but be able to catalyze a much wider range of reactions with high chemo-, regio-, stereo-and enantioselectivity. Man-made organocatalysts are much smaller, cheaper and more stable than enzymes.

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“…In this respect, this rate acceleration is modest compared to natural enzyme equivalent. [16][17][18] In addition, methanolysis of 7-acetoxy-4-methylcoumarin was enhanced about 6-fold by succinoglycan, acid polysaccharide from Rhizobium meliloti. 19 We also investigated the methanolysis reaction by glucose (4 and 88 mM) and β-cyclodextrin (β-CD, 4 and 12 mM) to identify the effect of other typical carbohydrates.…”

mentioning

confidence: 99%