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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Strong Bases and beyond: The Prominent Contribution of Neutral Push–Pull Organic Molecules towards Superbases in the Gas Phase

International Journal of Molecular Sciences, Год журнала: 2024, Номер 25(11), С. 5591 - 5591

Опубликована: Май 21, 2024

In this review, the principles of gas-phase proton basicity measurements and theoretical calculations are recalled as a reminder how PA/GB scale, based on Brønsted–Lowry theory, was constructed in (PA—proton affinity and/or GB—gas-phase enthalpy Gibbs energy respectively). The origins exceptionally strong some organic nitrogen bases containing N-sp3 (amines), N-sp2 (imines, amidines, guanidines, polyguanides, phosphazenes), N-sp (nitriles) rationalized. particular, role push–pull development superbasicity region is emphasized. Some reasons for difficulties poly-functional highlighted. Various structural phenomena being relation with acid–base equilibria that should be considered quantum-chemical parameters discussed. preparation methods site protonation briefly reviewed. Finally, recent trends research neutral superbases, leaning toward catalytic other remarkable applications, underlined.

Язык: Английский

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Asymmetric Synthesis of Hydroindoles via Desymmetrizing [3+2] Annulation of p-Quinamines and Arylalkylketenes

Organic Letters, Год журнала: 2024, Номер 26(16), С. 3366 - 3370

Опубликована: Апрель 12, 2024

The asymmetric desymmetrizing [3+2] annulation reaction of p-quinamines and arylalkylketenes to synthesize hydroindoles was realized. Catalyzed by chiral bisguanidinium hemisalt via multiple hydrogen bond interactions, enantiomerically enriched products with reversal diastereoselectivity in comparison the racemic version were afforded good yields under mild conditions. Diaryl-substituted could also perform Friedel–Crafts type addition give more complicated multicycles. Density functional theory calculations revealed that enantio- stem from varied hydrogen-bonding manners.

Язык: Английский

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Regioselectivity of conjugate addition of secondary amines and thiols to α-substituted enyne aldehydes

Tetrahedron, Год журнала: 2025, Номер unknown, С. 134494 - 134494

Опубликована: Янв. 1, 2025

Язык: Английский

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Mechanistic Study on the Asymmetric Cascade Michael Addition of Alkynone and Oxindole Catalyzed by Chiral Guanidine

The Journal of Organic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Март 26, 2025

Density functional theory (DFT) calculations with the M06-2X-D3 were used to get mechanistic investigation and stereoselectivity of cascade Michael addition alkynone oxindole, catalyzed by a chiral guanidine-amide compound. The reaction proceeded through two-step synergistic process involving sequential C–C C–O bond formation, together an H-shift. Because high energy barriers 33.5 kcal mol−1 (for construction) 41.3 mol–1 construction), was difficult proceed without catalyst. guanidine catalyst facilitated generation enolized oxindole species nucleophilicity, activating both enolate via ion-pairing multiple hydrogen bonding, significantly lowering activation barriers. combination unit sulfonamide backbone created excellent semiclosed environment, promoting asymmetric induction. Due steric effects from ortho- para-substituted iPr groups in SO2Ar, bulky Cy group, backbone, SS-configuration spirocyclization product enantio- diastereoselectivity formed predominantly. E/Z selectivity formation key α,β-unsaturated ketone intermediate influenced catalyst-substrate interactions. Extension alkyl chain at 3-position substrate led more difficult, hindering construction spirooxindoles.

Язык: Английский

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Markovnikov Protoborylation of Unactivated Terminal Alkenes via Copper-Guanidine Catalysis

The Journal of Organic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Май 23, 2025

Herein copper-catalyzed Markovnikov protoborylation of unactivated terminal alkenes was achieved through the employment a bulky σ-donating guanidine ligand. The reaction demonstrated good tolerance to diverse functional groups and remarkable selectivity for branched borylation products (86:14-97:3) under ambient conditions, which enabled synthesis secondary alkyl boronates in grams with further valuable derivatizations. Mechanistic studies suggested boryl insertion C═C bonds via Cu-guanidine complex ruled out possibility diboration-protodeboronation process.

Язык: Английский

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Asymmetric construction of spirobenzofuran indolinones via cascade reaction of 3-hydroxyoxindoles with coumarins

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(23), С. 6813 - 6818

Опубликована: Янв. 1, 2024

A series of enantioenriched spirobenzofuran indolinones were afforded via an asymmetric organocatalytic cascade reaction 3-hydroxyoxindoles with coumarins. Meanwhile, the stereo-determining step was disclosed.

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, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 2, 2024

Abstract 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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The Enantiopure 1,2-Diphenylethylenediamine (DPEDA) Motif in the Development of Organocatalysts for Asymmetric Reactions: Advances in the Last 20 Years

Catalysts, Год журнала: 2024, Номер 14(12), С. 915 - 915

Опубликована: Дек. 12, 2024

1,2-Diphenylethylenediamine (DPEDA) is a privileged chiral scaffold being used in the construction of broad variety organocatalysts and ligands for enantioselective organic reactions. This molecule gave significant contribution synthesis structurally different bi/multifunctional organocatalysts. DPEDA played an essential role development capable yielding important information on reaction mechanisms, like enamine, iminium, hydrogen-bonding anion-binding catalysis. The aim present review to highlight summarize achievements reached last 20 years (2004–2024) chemistry DPEDA-based asymmetric synthesis.

Язык: Английский

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