Halogen, Chalcogen, Pnictogen, and Tetrel Bonding in Non‐Covalent Organocatalysis: An Update

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(31)

Опубликована: Май 11, 2024

The use of noncovalent interactions based on electrophilic halogen, chalcogen, pnictogen, or tetrel centers in organocatalysis has gained noticeable attention. Herein, we provide an overview the most important developments last years with a clear focus experimental studies and catalysts which act via such non-transient interactions.

Язык: Английский

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Harnessing Multistep Chalcogen Bonding Activation in the α-Stereoselective Synthesis of Iminoglycosides

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(15), С. 10608 - 10620

Опубликована: Апрель 2, 2024

The use of noncovalent interactions (NCIs) has received significant attention as a pivotal synthetic handle. Recently, the exploitation unconventional NCIs gained considerable traction in challenging reaction manifolds such glycosylation due to their capacity facilitate entry into difficult-to-access sugars and glycomimetics. While investigations involving oxacyclic pyrano- or furanoside scaffolds are relatively common, methods that allow selective synthesis biologically important iminosugars comparatively rare. Here, we report phosphonochalcogenide (PCH) catalyze stereoselective α-iminoglycosylation iminoglycals with wide array glycosyl acceptors remarkable protecting group tolerance. Mechanistic studies have illuminated counterintuitive role catalyst serially activating both donor acceptor up/downstream stages through chalcogen bonding (ChB). dynamic interaction chalcogens substrates opens up new mechanistic opportunities based on iterative ChB engagement disengagement multiple elementary steps.

Язык: Английский

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A Hexavalent Tellurium-Based Chalcogen Bonding Catalysis Platform: High Catalytic Activity and Controlling of Selectivity

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 13, 2025

Herein, we describe a hexavalent tellurium-based chalcogen bonding catalysis platform capable of addressing reactivity and selectivity issues. This research demonstrates that tellurium salts can serve as class highly active catalysts for the first time. The centers in these have only one exposed interaction site, thus providing favorable condition controlling reaction selectivity. advantages were demonstrated by their remarkable catalytic activity cyanidation difluorocyclopropenes through C-F bond activation, which otherwise low reactive under strong Lewis acids or inaccessible representative divalent/tetravalent donors. catalyst was further highlighted its capability to address previously unresolved problem associated with acid approach, upon using some less silyl enol ethers nucleophiles functionalization difluorocyclopropenes. generality this versatile application different systems. differentiate two similar free OH groups glycosyl acceptors achieve excellent regio- stereoselectivity synthesis disaccharides, tetravalent gave Mechanistic investigation suggests catalyst-glycosyl donor-acceptor ternary supramolecular complex is operative.

Язык: Английский

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Stereoselective Entry into α,α’‐C‐Oxepane Scaffolds through a Chalcogen Bonding Catalyzed Strain‐Release C‐Septanosylation Strategy

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(29)

Опубликована: Апрель 30, 2024

Abstract The utility of unconventional noncovalent interactions (NCIs) such as chalcogen bonding has lately emerged a robust platform to access synthetically difficult glycosides stereoselectively. Herein, we disclose the versatility phosphonochalcogenide (PCH) catalyst facilitate into challenging, but biologically interesting 7‐membered ring α,α’‐ C ‐disubstituted oxepane core through an α‐selective strain‐release ‐glycosylation. Methodically, this strategy represents switch from more common entropically less desired macrocyclizations thermodynamically favored ring‐expansion approach. In light general lack stereoselective methods ‐septanosides, remarkable palette silyl‐based nucleophiles can be reliably employed in our method. This include broad variety useful synthons, easily available silyl‐allyl, silyl‐enol ether, silyl‐ketene acetal, vinylogous silyl‐alkyne and silylazide reagents. Mechanistic investigations suggest that mechanistic shift towards intramolecular aglycone transposition involving pentacoordinate silicon intermediate is likely responsible steering stereoselectivity.

Язык: Английский

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Recent Advances and Strategies towards Synthesis of Indolyl and Tryptophan‐C‐Glycoside Scaffolds

Advanced Synthesis & Catalysis, Год журнала: 2024, Номер 366(7), С. 1484 - 1508

Опубликована: Фев. 29, 2024

Abstract Recently, C ‐glycosidic bonds have emerged as pivotal elementary units present in many naturally occurring alkaloids well pharmaceutically active molecules. Because of the stability and great utility ‐glycosides, synthetic approaches en route to C−C bond formation gradually become a center attraction carbohydrate chemistry. Towards these researches, ‐glycosylation with heteroaryl moieties like indole, tryptophan can remarkably expand functional structural evolution, which has value for medicinal chemists chemical biologists. The indolyl tryptophan‐ ‐glycosides unique structures biological activities that attracted number studies. Therefore, motifs possessed an extensive interest direction efficient synthesis. Herein, this review systematically summarizes classical ‐heteroaryl glycosides mainly focusing on indole Furthermore, highlighted recently developed metal‐catalyzed C−H functionalization photoinduced cross‐coupling strategies aim control regioselectivity diastereoselectivity reaction In view type, mechanism, status, will cover synthesis diverse regio‐ from four perspectives include a) conventional approach, b) heterocyclization sequence, c) functionalization, d) cross‐coupling. 1. Introduction 2. Strategies 2.1. Conventional approach 2.2. Heterocyclization sequence 2.3. Metal‐catalyzed 2.4. Photoinduced 3. Summary Outlook

Язык: Английский

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Pnictogen‐Bonding Enzymes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(45)

Опубликована: Июль 5, 2024

Abstract The objective of this study was to create artificial enzymes that capitalize on pnictogen bonding, a σ‐hole interaction is essentially absent in biocatalysis. For purpose, stibine catalysts were equipped with biotin derivative and combined streptavidin mutants identify an efficient transfer hydrogenation catalyst for the reduction fluorogenic quinoline substrate. Increased catalytic activity from wild‐type best coincides depth σ hole Sb(V) center, emergence saturation kinetic behavior. Michaelis–Menten analysis reveals transition‐state recognition low micromolar range, more than three orders magnitude stronger millimolar substrate recognition. Carboxylates preferred by contribute hydrogen‐bonded ion pairing anion‐π interactions emerging pyridinium product. challenging stereoselectivity aqueous systems further emphasizes compatibility bonding higher order catalysis.

Язык: Английский

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Neutral Chalcogen Bonding Enabled Photoinduced Cross‐Electrophile C—S/Se Coupling of Aryl Iodides via S_RN1 Process

Chinese Journal of Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Март 7, 2025

Comprehensive Summary Cross‐coupling reactions between aryl halides and thiolates or selenolates typically require transition metals, photocatalysts, strong bases, or/and malodorous thiols/selenols, with various mechanisms proposed. This study aims to leverage a new application of neutral ChB address these challenges enable very simple photoinduced cross‐electrophile C—S/Se coupling using readily available chalcogen electrophiles. Mechanistic investigations have revealed the important role in facilitating single electron transfer processes, thereby enabling generation thiolates/selenolates from stable electrophiles α ‐aminoalkyl radicals, which possess capability abstract halogen atoms iodides. Moreover, provided support for radical nucleophilic substitution mechanism.

Язык: Английский

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Hydrogen-Bond-Mediated Glycosylation Reactions with Glycosyl Picolinates

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Апрель 11, 2025

Herein, we report a generally applicable hydrogen-bond-mediated glycosylation protocol of glycosyl picolinate donors with charged (thio)urea hydrogen-bond-donor catalyst. A variety nucleophiles, including complex natural products, glycosides, amino acids, and less nucleophilic phenolic acceptors were also glycosylated successfully. Hydrogen-bond-mediated systems combined different strategies explored to achieve stereoselective glycosylation. mechanistic study revealed that catalysts form the donor-catalyst noncovalent through hydrogen bonds then produce oxocarbenium species.

Язык: Английский

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Glycosylidene-carbene-mediated homologation of boronic esters for the synthesis of boro-ketosides

Chem Catalysis, Год журнала: 2024, Номер 4(4), С. 100946 - 100946

Опубликована: Март 8, 2024

Язык: Английский

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Asymmetric Carbene Insertion into Se‐S Bonds by Synergistic Rh(II)/Guanidine Catalysis Involving Chalcogen‐Bond Assistance

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 2, 2024

The efficient construction of chalcogen-atom-based chiral compounds remains a challenge, despite the importance organoselenium and organosulfur in life materials science. Chalcogen atoms can form net attractive interactions called chalcogen bonds, but it is an undeveloped tool to assist asymmetric catalysis. Herein, we report enantioselective insertion platform install stereogenic center bearing selenyl thiocyano functional groups. Our method operates by synergistic catalysis guanidine achiral dirhodium complex three-component or four-component reaction, through Se-S bond into carbene species, competing successfully with spontaneous racemic process showing high regioselectivity. As elucidated spectroscopic experiments computational studies, unique mechanism involving as well hydrogen bonding was established account for enantiocontrol. stereoselectivity holds broad array selenylthiocyanatopropanoates, which showed excellent anti-inflammatory toward IL-1β low cytotoxicity.

Язык: Английский

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