Palladium‐Catalyzed [4+2] and [6+2] Dipolar Cycloadditions for the Construction of Benzo[d]isothiazole 1,1‐Dioxide Fused 1,3‐Oxazinanes and 1,3‐Oxazocanes^†

Chinese Journal of Chemistry, Год журнала: 2023, Номер 42(8), С. 829 - 834

Опубликована: Дек. 8, 2023

Comprehensive Summary The Pd‐catalyzed dipolar cycloaddition represents a significant synthetic strategy for the construction of useful heterocyclic compounds. This study developed [4+2] and [6+2] reactions benzo[ d ]isothiazole 1,1‐dioxides (BDs) leading to synthesis BD‐fused 1,3‐oxazinane 1,3‐oxazocane derivatives, respectively. In particular, 1,3‐oxazinanes demonstrated regio‐ enantioselective characteristics, resulting in products with good yields, enantioselectivity regioselectivity (if applicable). Furthermore, reaction this work represented first medium‐sized ring compounds based on BDs.

Язык: Английский

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Synthesis of N-alkoxy amines and hydroxylamines via the iridium-catalyzed transfer hydrogenation of oximes

Organic & Biomolecular Chemistry, Год журнала: 2022, Номер 20(32), С. 6394 - 6399

Опубликована: Янв. 1, 2022

An efficient and practical strategy for the construction of N -alkoxy amines hydroxylamines through corresponding oximes is described via an Ir-catalyzed acid-assisted system with high yields a good substrate scope.

Язык: Английский

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Catalysis, kinetics and mechanisms of organo-iridium enantioselective hydrogenation-reduction

Catalysis Science & Technology, Год журнала: 2019, Номер 10(3), С. 590 - 612

Опубликована: Дек. 11, 2019

The synthesis of chiral molecules is great importance to the pharmaceutical, agrochemical, flavour and fragrance industries.

Язык: Английский

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Asymmetric Transfer Hydrogenation of α,β‐Unsaturated Carbonyl Compounds to Saturated Alcohols as Catalyzed by Iridium Complexes of Tricyclic Bioxazoline‐Fused Imidazole‐Derived N‐Heterocyclic Carbene Ligands

ChemistrySelect, Год журнала: 2019, Номер 4(1), С. 357 - 365

Опубликована: Янв. 8, 2019

Abstract A series of chiral iridium(I) ( 1 ‐ 3 ) e complexes bioxazoline fused imidazole derived N‐heterocyclic carbene (NHC) ligands successfully carried out asymmetric transfer hydrogenation α , β ‐unsaturated ketones in good to excellent yields ca . 36‐91%) and low enantioselectivites 5‐31% ee at mol % the catalyst loading presence NaOH as a base i ‐PrOH 75° C hours reaction time. The were synthesized directly from NHC precursors namely {(3 R ,7 )‐3,7‐di‐R‐2,3,7,8‐tetrahydrodioxazolo[3,2‐c:3′,2′‐e]imidazol‐4‐ium trifluoromethanesulfonate, R= s ‐butyl d ), 2 ‐propyl )} by treatment with {(COD)IrCl} (COD=1,5‐cyclooctadiene) t ‐BuOK room temperature. ligand commercially available optically pure amino acids sequence reactions without requiring any resolution.

Язык: Английский

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Recent Advances in the Syntheses and Catalytic Applications of Homonuclear Ru‐, Rh‐, and Ir‐Complexes of C_NHC^C Cyclometalated Ligands

Chemistry - A European Journal, Год журнала: 2021, Номер 27(67), С. 16581 - 16600

Опубликована: Сен. 1, 2021

In the past few decades, chemistry of cyclometalated species has gained momentum with increased applications in several areas scientific developments. Cyclometalation reactions result formation stable metallacycles through generation metal-carbon covalent bonds by activating unreactive Csp2 -H or Csp3 bonds. The extra stability enhances their applicability scopes especially area homogeneous catalysis. recent research development this area, NHC ligands (strong σ-donor and generally, weak π-acceptor) have been found to be one most suitable candidates for intramolecular C-H activation process which leads species. growth cyclometalation that started late 20th century is still continuing various examples derived transition metal-based complexes came into picture. As covering all reported literatures (includes mainly metals) will exceed limits minireview, we restricted ourselves (2015 - May 2021) common Ru-, Rh-, Ir-based CNHC ^C catalytic conversions such as transfer hydrogenation, amidation, oxidation alcohols, annulations, so forth.

Язык: Английский

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Dual Role of Vinyl Sulfonamides as N‐Nucleophiles and Michael Acceptors in the Enantioselective Synthesis of Bicyclic δ‐Sultams

Advanced Synthesis & Catalysis, Год журнала: 2018, Номер 360(15), С. 2885 - 2893

Опубликована: Май 30, 2018

Abstract A new methodology for the synthesis of enantiomerically enriched bicyclic δ‐sultams is described, involving an initial organocatalytic intramolecular aza‐Michael reaction vinyl sulfonamides bearing a conjugated ketone at remote position. The resulting Michael adducts were then subjected to conjugate addition over sulfone moiety, thus rendering final sultams containing two stereocenters. key point this strategy relies on use as both, nitrogen nucleophiles and acceptors. phosphazene‐derived bases avoided racemization intermediate derivatives, 6‐membered ring in manner with small erosion enantiopurity. Anyway, after recrystallization, obtained almost pure form. Nevertheless, enantioselective either 5‐membered products or benzofused derivatives was found be out scope our strategy. magnified image

Язык: Английский

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A kinetic resolution strategy for the synthesis of chiral octahedral NHC–iridium(iii) catalysts

Chemical Communications, Год журнала: 2019, Номер 55(43), С. 6058 - 6061

Опубликована: Янв. 1, 2019

The transmetalation reaction of a chiral-bidentate NHC–silver complex to racemic [lr(μ-Cl)(ppy)₂]₂ operates with kinetic resolution leading chiral octahedral NHC–iridium(iii) complexes and enantio-enriched bis-cyclometalated iridium(iii) complexes.

Язык: Английский

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Bis-Cyclometalated Indazole and Benzimidazole Chiral-at-Iridium Complexes: Synthesis and Asymmetric Catalysis

Molecules, Год журнала: 2021, Номер 26(7), С. 1822 - 1822

Опубликована: Март 24, 2021

A new class of bis-cyclometalated iridium(III) catalysts containing two inert cyclometalated 6-tert-butyl-2-phenyl-2H-indazole bidentate ligands or 5-tert-butyl-1-methyl-2-phenylbenzimidazoles is introduced. The coordination sphere complemented by labile acetonitriles, and a hexafluorophosphate ion serves as counterion for the monocationic complexes. Single enantiomers chiral-at-iridium complexes (>99% er) are obtained through chiral-auxiliary-mediated approach using monofluorinated salicyloxazoline investigated in enantioselective conjugate addition indole to an α,β-unsaturated 2-acyl imidazole asymmetric Nazarov cyclization.

Язык: Английский

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Synthesis and Application of Planar Chiral Cyclic (Amino)(ferrocenyl)carbene Ligands Bearing FeCp* Group

Organometallics, Год журнала: 2019, Номер 38(9), С. 2211 - 2217

Опубликована: Май 2, 2019

New cyclic (amino)(ferrocenyl)carbene (CAFeC) ligands containing the Cp* group have been developed as a modification of their prototype Cp version. The generation new carbenes was indirectly confirmed by trapping experiments in which carbene precursor reacted with sulfur or [IrCl(cod)]2 presence base. electronic properties CAFeCs were evaluated determining Tolman parameter (TEP) Ir dicarbonyl complex [IrCl(CO)2(CAFeC)] that synthesized via [IrCl(cod)(CAFeC)]. It revealed donor strengths very high and comparable to those (amino)(alkyl)carbenes (CAACs). influence steric effect on enantioselectivity changing be significant an Ir-catalyzed asymmetric transfer hydrogenation N-sulfonylimine where used chiral ligands.

Язык: Английский

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Redox‐Switchable Transfer Hydrogenations with P‐Chiral Dendritic Ferrocenyl Phosphine Complexes

European Journal of Inorganic Chemistry, Год журнала: 2020, Номер 2020(17), С. 1654 - 1669

Опубликована: Фев. 18, 2020

Attaining absolute control over a catalytic process and, therewith, exploiting its full potential pleases scientists in their ambitious and ongoing endeavor to perform catalysis like Nature does. In this regard, redox‐switchable certainly holds great potential, constantly gaining importance modern research. Herein, we report the application of P ‐stereogenic dendritic ferrocenyl phosphines ruthenium‐catalyzed transfer hydrogenation ketone yielding an enantioenriched alcohol. By adding chemical oxidant or reductant, activity complexes was reversibly switched off back on again course hydrogen reaction. This has been rationalized mainly terms distinct electronic communication between redox‐active group center. The highly functionalized catalysts presented here might impact way prospective homogeneous will be designed.

Язык: Английский

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