Catalytic Approaches to Chemo- and Site-Selective Transformation of Carbohydrates

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(10), P. 6793 - 6838

Published: April 26, 2023

Carbohydrates are a fundamental unit playing pivotal roles in all the biological processes. It is thus essential to develop methods for synthesizing, functionalizing, and manipulating carbohydrates further understanding of their functions creation sugar-based functional materials. is, however, not trivial such methods, since densely decorated with polar similarly reactive hydroxy groups stereodefined manner. New approaches chemo- site-selective transformations are, therefore, great significance revolutionizing sugar chemistry enable easier access sugars interest. This review begins brief overview innate reactivity carbohydrates. followed by discussions about catalytic enhance, override, or be orthogonal transformation avoids making list reactions, but rather focuses on summarizing concept behind each reported transformation. The literature references were sorted into sections based underlying ideas approaches, which we hope will help readers have better sense current state innovative field.

Language: Английский

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Carbene-catalyzed chirality-controlled site-selective acylation of saccharides

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 2, 2025

Acylation stands as a fundamental process in both biological pathways and synthetic chemical reactions, with acylated saccharides their derivatives holding diverse applications ranging from bioactive agents to building blocks. A longstanding objective organic synthesis has been the site-selective acylation of without extensive pre-protection alcohol units. In this study, we demonstrate that by simply altering chirality N-heterocyclic carbene (NHC) catalysts, site-selectivity saccharide reactions can be effectively modulated. Our investigation reveals intriguing selectivity shift stems combination factors, including match/mismatch inter- / intramolecular hydrogen bonding between NHC catalyst substrates. These findings provide valuable insights into design reaction engineering, highlighting potential glycoside analysis, such fluorescent labelling, α/β identification, orthogonal selective late-stage modifications. The units synthesis. Here, authors

Language: Английский

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Regioselective Substitution of BINOL

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(10), P. 6643 - 6689

Published: May 9, 2024

1,1′-Bi-2-naphthol (BINOL) has been extensively used as the chirality source in fields of molecular recognition, asymmetric synthesis, and materials science. The direct electrophilic substitution at aromatic rings optically active BINOL developed one most convenient strategies to structurally modify for diverse applications. High regioselectivity achieved reaction with electrophiles. Depending upon conditions patterns, various functional groups can be introduced specific positions, such 6-, 5-, 4-, 3-positions, BINOL. Ortho-lithiation 3-position directed by 2-position have prepare 3- 3,3′-substituted BINOLs. use transition metal-catalyzed C–H activation also explored functionalize 3-, 7-positions. These regioselective substitutions allowed construction tremendous amount derivatives fascinating structures properties reviewed this article. Examples applications BINOLs varying catalysis, chiral sensing are provided.

Language: Английский

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Electrochemical Synthesis of Glycosyl Fluorides Using Sulfur(VI) Hexafluoride as the Fluorinating Agent

Organic Letters, Journal Year: 2022, Volume and Issue: 24(12), P. 2294 - 2298

Published: March 17, 2022

This manuscript describes the electrochemical synthesis of 17 different glycosyl fluorides in 73-98% yields on up to a 5 g scale that relies use SF6 as an inexpensive and safe fluorinating agent. Cyclic voltammetry related mechanistic studies carried out subsequently suggest active species generated through cathodic reduction are transient under these reductive conditions sulfur fluoride byproducts effectively scavenged by Zn(II) generate benign salts.

Language: Английский

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A synergistic Rh(I)/organoboron-catalysed site-selective carbohydrate functionalization that involves multiple stereocontrol

Nature Chemistry, Journal Year: 2022, Volume and Issue: 15(3), P. 424 - 435

Published: Dec. 30, 2022

Abstract Site-selective functionalization is a core synthetic strategy that has broad implications in organic synthesis. Particularly, exploiting chiral catalysis to control site selectivity complex carbohydrate functionalizations emerged as leading method unravel unprecedented routes into biologically relevant glycosides. However, robust catalytic systems available overcome multiple facets of stereoselectivity challenges this end still remain scarce. Here we report synergistic Rh(I)- and organoboron-catalysed protocol, which enables access synthetically challenging but arylnaphthalene Our depicts the employment Rh(I) site-selective showcases utility boronic acid compatible co-catalyst. Crucial success our judicious choice suitable organoboron catalyst. We also determine exquisite aspects stereocontrol, including enantio-, diastereo-, regio- anomeric dynamic kinetic resolution, are concomitantly operative.

Language: Английский

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Asymmetric Transfer Hydrogenation of Heterocyclic Compounds in Continuous Flow Using an Immobilized Chiral Phosphoric Acid as the Catalyst

Synthesis, Journal Year: 2023, Volume and Issue: 55(15), P. 2361 - 2369

Published: May 3, 2023

Abstract This manuscript describes transfer hydrogenation of bicyclic nitrogen-containing heterocyclic compounds using the immobilized chiral phosphoric acid catalyst (R)-PS-AdTRIP in batch and continuous flow. A significant improvement enantioselectivities is achieved flow with a fluidized bed reactor packed when rate increased from 0.2 mL/min to 2.0–2.5 mL/min. The optimized conditions consistently provide 4–6% ee higher selectivity than 2 mol% (R)-PS-AdTRIP, are used generate multiple products same reactor.

Language: Английский

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Catalyst-Controlled, Site-Selective Functionalization of Levoglucosan Analogues Mediated by Chiral Zinc Diamine Complexes

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

In this work, we developed a site-selective functionalization of levoglucosan analogues. This strategy used simple zinc diamine complexes for regioselective at O2 or O4. Successful transformations monotosyl analogues allowed the preparation useful intermediates in carbohydrate chemistry, such as four protected Černý epoxides and three amino sugars. unique method represents rare use desymmetrization 1,3-diols.

Language: Английский

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Modular Synthesis and Cytotoxicity Evaluation of Dragocins A—C and Their Analogues: Discovery of a Potential Anticancer Agent

Chinese Journal of Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 11, 2025

Comprehensive Summary Dragocins A—C are structurally unique marine natural products featuring an uncommon tri‐oxa‐tricyclic[6.2.1]undecane moiety. However, their extremely low abundance has hindered extensive screening of bioactivities. We hereby describe efficient and modular approach to synthesizing dragocins analogues using commercially available inexpensive anisomycin D‐ribosyl thioglycoside derivative as the starting materials. A key feature our synthesis is construction skeleton. This challenging architecture achieved by stereocontrolled formation β‐ribofuranosidic bond DDQ (2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone)‐promoted intramolecular cross‐dehydrogenative etherification at benzylic position. Our also characterized successful installation a chlorine atom methoxy group tertiary C‐4' position via late‐stage silver‐catalyzed decarboxylative chlorination reaction electrophilic enol intermediate. Cytotoxicity evaluations synthesized compounds revealed demethyl dragocin A, N ‐demethylated potential anticancer candidate due its strong cytotoxicity against A549 lung, HCT116 colorectal MCF7 breast cancer cell lines. work demonstrated preliminary structure‐activity relationship this compound, setting solid foundation for developing novel candidates.

Language: Английский

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Rh(II) and Chiral Phosphoric Acid Co-catalyzed Selective O–H Insertions for Stereodivergent O-Alkylation of Glycosides

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 10, 2025

Carbohydrates are synthetically challenging molecules with essential biological functions in all living systems. The selective synthesis and modification of carbohydrates crucial for investigating their functions. Controlling chemo-, regio-, stereoselectivity is a central theme carbohydrate synthesis. Achieving the full set stereoisomers derivatives would significantly enhance efficiency building compound libraries studies drug discovery. However, functionalization seemingly identical hydroxyl groups remains long-standing challenge organic chemistry. In synthesis, achieving precise control both relative configurations catalyst-controlled reactions that create new stereocenter presents significant synthetic challenge. Herein, we developed an efficient method stereodivergent O-alkylation via Rh(II)/chiral phosphoric acid-cocatalyzed insertion metal carbenoids. This system mild robust, offering excellent selectivity across broad range substrates high regio- stereoselectivity. Furthermore, this strategy opens up vast opportunities

Language: Английский

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Controlling Stereoselectivity with Noncovalent Interactions in Chiral Phosphoric Acid Organocatalysis

Chemical Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: March 18, 2025

Chiral phosphoric acids (CPAs) have emerged as highly effective Brønsted acid catalysts in an expanding range of asymmetric transformations, often through novel multifunctional substrate activation modes. Versatile and broadly appealing, these benefit from modular tunable structures, compatibility with additives. Given the unique types noncovalent interactions (NCIs) that can be established between CPAs various reactants─such hydrogen bonding, aromatic interactions, van der Waals forces─it is unsurprising catalyst systems become a promising approach for accessing diverse chiral product outcomes. This review aims to provide in-depth exploration mechanisms by which impart stereoselectivity, positioning NCIs central feature connects broad spectrum catalytic reactions. Spanning literature 2004 2024, it covers nucleophilic additions, radical atroposelective bond formations, highlighting applicability CPA organocatalysis. Special emphasis placed on structural mechanistic features govern CPA-substrate well tools techniques developed enhance our understanding their behavior. In addition emphasizing details stereocontrolling elements individual reactions, we carefully structured this natural progression specifics broader, class-level perspective. Overall, findings underscore critical role catalysis significant contributions advancing synthesis.

Language: Английский

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