A peptide-based catalyst approach to regioselective functionalization of carbohydrates

Griswold, Keith S.; Miller, Scott J.

doi:10.1016/j.tet.2003.05.002

Cited by 144 publications

(82 citation statements)

References 21 publications

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“…Procedure for Chart 3 Racemic-12 (100 mg, 0.51 mmol) was dissolved in 12 N HCl (2.0 mL) and stirred under reflux for 7 h. The mixture was concentrated in vacuo to give a solid of racemic-4 containing NH 4 Cl. The solid was stirred at 180°C in vacuo for 1 h to sublimate NH 4 Cl and give pure racemic-4 as a colorless solid (140 mg, quant.).…”

Section: Methodsmentioning

confidence: 99%

“…The solid was stirred at 180°C in vacuo for 1 h to sublimate NH 4 Cl and give pure racemic-4 as a colorless solid (140 mg, quant.). To a stirred mixture of racemic-4 (500 mg, 1.8 mmol), 13 (1.3 g, 3.8 mmol) and Nmethylmorpholine (0.71 mL, 6.4 mmol) in dichloromethane (DCM) (10 mL), were added N-hydroxybenzotriazole (HOBt) (0.74 g, 5.5 mmol) and WSC·HCl (1.1 g, 5.5 mmol) at r.t. After 24 h, DCM was removed in vacuo and the residue was dissolved in AcOEt (20 mL), washed with saturated aqueous NaHCO 3 (10 mL), H 2 O (10 mL) and brine (10 mL), dried over Na 2 SO 4 , filtered and concentrated in vacuo.…”

Section: Methodsmentioning

confidence: 99%

“…[1][2][3][4][5][6] Especially, C 2 -symmetric-2,5-disubstituted PPY is a privileged structure for site-and chemoselective molecular transformation. For example, catalyst 1 was found to be effective for site-selective acylation of glycopyranoside derivatives, [7][8][9][10][11] chemoselective monoacylation of linear diols, 12) and site-selective acylation of a cardiac glycosides, digitoxin 13) and lanatoside C (5) 14) (Fig.…”

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confidence: 99%

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A Concise Access to C2-Symmetric Chiral 4-Pyrrolidinopyridine Catalysts with Dual Functional Side Chains

Mishiro

Takeuchi

Furuta

et al. 2016

CHEMICAL & PHARMACEUTICAL BULLETIN

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A practical method was developed for the preparation of a diastereomeric library of C 2 -symmetric chiral 4-pyrrolidinopyridine catalysts with dual amide side chains. Use of a racemic precursor is the key to the concise production of catalysts with diverse stereochemisty.Key words organocatalyst; C 2 -symmetry; pyrrolidinopyridine; catalyst library; racemic precursor Various chiral 4-dimethylaminopyridine (DMAP) and 4-pyrrolidinopyridine (PPY) derivatives have been developed and extensively employed in asymmetric acyl transfer and the related reactions.1-6) Especially, C 2 -symmetric-2,5-disubstituted PPY is a privileged structure for site-and chemoselective molecular transformation. For example, catalyst 1 was found to be effective for site-selective acylation of glycopyranoside derivatives, 7-11) chemoselective monoacylation of linear diols, 12) and site-selective acylation of a cardiac glycosides, digitoxin 13) and lanatoside C (5) 14) (Fig. 1). Highly geometryselective acylation of tetra-substituted α,α′-alkenediols has been also achieved by employing catalyst 2a.15) Catalyst 2b was found to be effective for chemoselective acylation of sterically hindered secondary alcohols in the presence of otherwise more reactive primary alcohols.16) Asymmetric desymmetrization of meso-diols has been performed by catalyst 3 17) (Fig. 1). All of these C 2 -symmetric PPY catalysts have been prepared from versatile precursor 4. 7)For the above-mentioned site-and chemoselective molecular transformations, precise molecular recognition process between the catalysts and the substrates seems to be involved. 18,19) The amide side chains at C(2) and C(5) of the pyrrolidine ring are assumed to be responsible for the molecular recognition process. Therefore, preparation of all four possible isomers of C 2 -symmetric PPY catalysts with dual chiral amide side chains at C(2) and C(5) such as 1, 1a, ent-1, and ent-1a seemed to be meaningful for optimizing the conditions for the targeted site-selective molecular transformation (Fig. 2). For example, site-selective acylation of lanatoside C (5) took place at the C(4⁗)-OH in 86% site-selectivity among eight hydroxy groups in the different micro environments in the presence of catalyst 1 14) (Fig. 2). On the other hand, the diastereomeric and enantiomeric catalysts 1a, ent-1, and ent-1a gave the C(4⁗)-, C(3⁗)-, and C(3⁗)-O-acylates as the major acylate in 73, 62, and 80% site-selectively, respectively. Accordingly, site-selectivity of the acylation was critically affected by the nature and stereochemistry of the amide side chains at C(2) and C(5) of the pyrrolidine ring of the PPY catalysts.These four diastereomeric catalysts have been prepared from versatile precursor 4 and its enantiomer. We have reported a method for the preparation of 4 starting from L-pyroglutamic acid (6) via tedious five-step sequence in 16% overall yield 7) (Fig. 3A). Large-scale preparation of 4 has been often problematic because of poor reproducibility of the transformation from 7 to 8 with catalytic amount of CuI....

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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A Concise Access to C2-Symmetric Chiral 4-Pyrrolidinopyridine Catalysts with Dual Functional Side Chains

Mishiro

Takeuchi

Furuta

et al. 2016

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Combinatorial methods are therefore appealing for the discovery of catalytically active peptides and have proven successful for the identification of, for example, highly active and selective acylation catalysts by Miller and coworkers. 1,10,11 However, the screening of combinatorial libraries requires either efficient high-throughput automation for the testing of parallel libraries or smart screening methods that allow for the detection of catalytically active compounds in split-and-mix libraries. 1,12,13 We developed the screening method of ''catalystsubstrate coimmobilization'' that allows for the identification of catalytically active compounds within split-and-mix libraries for essentially any bimolecular reaction.…”

Section: Introductionmentioning

confidence: 99%

Solid‐supported and pegylated H–Pro–Pro–Asp–NHR as catalysts for asymmetric aldol reactions

et al. 2005

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H-Pro-Pro-Asp-NH2 is a highly active and selective catalyst for asymmetric aldol reactions. Here, the versatility of H-Pro-Pro-Asp-NH2 has been further improved by immobilization on a solid support and functionalization with a short polyethylene glycol linker at the C-terminus. The development, synthesis, and the catalytic properties in aldol reactions of H-Pro-Pro-Asp-resin and H-Pro-Pro-Asp-Ahx-NH(CH2CH2O)3CH3 are described. For the solid-supported catalyst, TentaGel with a loading of 0.1-0.2 mmol g(-1) proved to be the optimal support. The solid-supported catalyst can be recycled at least three times without a significant drop in the catalytic activity or selectivity. Using the pegylated catalyst H-Pro-Pro-Asp-Ahx-NH(CH2CH2O)3CH3, only 0.5 mol % are necessary to obtain aldol products in up to 96% yield and 91% enantiomeric excess. In all cases, enantioselectivities are comparable to those obtained with the parent catalyst H-Pro-Pro-Asp-NH2. Thus, immobilization of H-Pro-Pro-Asp-NH2 on Tentagel as well as pegylation led to catalysts with selectivities comparable to the nonmodified catalyst, exhibiting additional distinct advantages such as facile reusability, ease of handling, higher solubility, and thereby greater versatility. handling, higher solubility, and thereby greater versatility.

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“…[91] Moderate bis gute Chemoselektivitäten konnten mit Peptidkatalysatoren in der Acylierung von Carbohydraten erzielt werden. [92,93] Gly betont die Verwandtschaft zu den entsprechenden aAminosäuren) [95] führt zu einem lipophileren und strukturell weniger flexiblen Oligopeptid, das in nichtpolaren organischen Lösungsmitteln gut löslich ist. eeWerte von typischerweise > 99 % (für das verbleibende Diol) und S-Werte > 50 konnten in der kinetischen Racematspaltung von trans-Cycloalkan-1,2-diolen 148 erzielt werden (Schema 23).…”

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Organokatalytischer, enantioselektiver Acyltransfer auf racemische sowie meso‐Alkohole, ‐Amine und ‐Thiole

2011

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Der Acyltransfer ist ein Paradebeispiel für den Transfer funktioneller Gruppen, sowohl in der Natur als auch im chemischen Labor. Acylierungen sind am Aufbau komplexer natürlicher Moleküle beteiligt und spielen eine entscheidende Rolle für den biologischen Energietransport. Die Charakterisierung kovalenter Acyl‐Enzym‐Intermediate trieb sowohl mechanistische Studien als auch die Entwicklung biomimetischer Verfahren an. Folglich verwendeten Chemiker zunächst die Werkzeuge der Natur in Form von Enzymen und natürlichen Alkaloiden als Katalysatoren, um schließlich eine Vielzahl kleiner, synthetischer Moleküle für den selektiven Acyltransfer zu entwickeln. Anders als die Natur nutzen Chemiker praktische Acylierungsreaktionen für die Stereoselektion und zum Schutz funktioneller Gruppen. Die Zahl der Studien zum Acyltransfer hat in den letzten 15 Jahren deutlich zugenommen. Dieser Aufsatz beschreibt diese Entwicklungen mit einem Schwerpunkt auf den im Titel genannten Substanzklassen.

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A peptide-based catalyst approach to regioselective functionalization of carbohydrates

Cited by 144 publications

References 21 publications

A Concise Access to <i>C</i><sub>2</sub>-Symmetric Chiral 4-Pyrrolidinopyridine Catalysts with Dual Functional Side Chains

A Concise Access to <i>C</i><sub>2</sub>-Symmetric Chiral 4-Pyrrolidinopyridine Catalysts with Dual Functional Side Chains

Solid‐supported and pegylated H–Pro–Pro–Asp–NHR as catalysts for asymmetric aldol reactions

Organokatalytischer, enantioselektiver Acyltransfer auf racemische sowie meso‐Alkohole, ‐Amine und ‐Thiole

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