The Effect of Basic Ligands and Alkenes on the Regioselectivity of C−H Additions of Tertiary Amines to Alkenes

Chemistry - A European Journal, Год журнала: 2024, Номер 30(32)

Опубликована: Апрель 4, 2024

Abstract Highly regioselective C−H alkylation reactions of tertiary anilines and alkyl amines with simple alkenes have been achieved by the use imidazolin‐2‐iminato scandium complexes. This protocol provided an efficient atom‐economical route to structurally diverse amine derivatives. The basic ligand, a coordinating THF in catalyst substitution alkene substrates were found switch regioselectivity presumably due generation different types catalytically active species or formation relatively stable intermediates. On basis deuterium labeling experiments KIE experiments, possible catalytical cycles understand reaction mechanism as well regioselectivity.

Язык: Английский

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Accessing secondary amine containing fine chemicals and polymers with an earth-abundant hydroaminoalkylation catalyst

Green Chemistry, Год журнала: 2023, Номер 25(7), С. 2629 - 2639

Опубликована: Янв. 1, 2023

Titanium-catalyzed hydroaminoalkylation has emerged as an atom-economical, earth-abundant synthesis of N-containing products.

Язык: Английский

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Iridium-, Ruthenium-, and Nickel-Catalyzed C–C Couplings of Methanol, Formaldehyde, and Ethanol with π-Unsaturated Pronucleophiles via Hydrogen Transfer

The Journal of Organic Chemistry, Год журнала: 2022, Номер 88(8), С. 4965 - 4974

Опубликована: Ноя. 30, 2022

In this Perspective, the use of methanol and ethanol as C1 C2 feedstocks in metal-catalyzed C-C couplings to π-unsaturated pronucleophiles via hydrogen auto-transfer is surveyed. these processes, alcohol oxidation form an aldehyde electrophile balanced by reduction hydrocarbon a transient organometallic nucleophile. Mechanistically related reductive paraformaldehyde mediated reductants or formic acid also are described. These processes encompass first catalytic enantioselective and, more broadly, illustrate how native reducing ability alcohols enable departure from premetalated reagents carbonyl addition.

Язык: Английский

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B(C₆F₅)₃-Catalyzed C(sp³)–H Alkylation of Tertiary Amines with Electron-Deficient Olefins: Determinants of Site Selectivity

ACS Catalysis, Год журнала: 2024, Номер 14(10), С. 8041 - 8049

Опубликована: Май 8, 2024

The reason for the site selectivity previously reported B(C6F5)3-catalyzed C(sp3)–H alkylation of tertiary amines with electron-deficient olefins remains a mystery. appears to be governed by number electron-withdrawing groups (EWGs) on olefin: one EWG results in α-alkylation, whereas two EWGs (one each end double bond) result β-alkylation. In this study, we solved mystery and unlocked pathway β-alkylation bearing only EWG. Control experiments density functional theory calculations provided detailed picture reaction mechanism both α- Furthermore, demonstrated broad scope reaction.

Язык: Английский

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Synthesis and Reactivity of a Bipyridyl Tantalum Complex

Inorganic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 9, 2025

The bipyridyl tantalum complex (2,6-iPr2C6H3O)3Ta(bipy) (2) is synthesized by the reaction of (2,6-iPr2C6H3O)3TaCl2 (1) and 2,2′-bipyridine in presence excess potassium graphite (KC8). Complex 2 coordinates readily with pyridine 4-(dimethylamino)pyridine (dmap) to form Lewis base adducts (2,6-iPr2C6H3O)3Ta(bipy)(L) (L = py (3), dmap (4)), it exhibits rich redox reactivity toward small molecules: (a) single electron transfer (SET) occurs upon exposure phenyl sulfide or selenide dimer, giving open-shell, bipy-centered radical complexes (2,6-iPr2C6H3O)3Ta(bipy•)(PhE) (E S (5), Se (6)). (b) Regioselective C–C σ-bond formation via coupling observed SET aldehydes, ketones, imines furnish insertion products 7–13, namely, sterically more crowded benzophenone, acetophenone, 2,6-dichlorobenzaldehyde, benzophenone imine couple C6 C6′ bipy 2, respectively, whereas less hindered benzaldehyde, cyclohexanone, benzylideneaniline C2 C2′ bipy, respectively. (c) serves as a synthon for (2,6-iPr2C6H3O)3Ta(III) contact diazene, organic azides, 1,4-diaza-1,3-diene (conjugated)alkyne derivatives, which imido/azido/hydrazido (2,6-iPr2C6H3O)3Ta(═NPh)(bipy0) (14), (2,6-iPr2C6H3O)3Ta(═N3(2,6-iPr2C6H3))(bipy0) (15), (2,6-iPr2C6H3O)3Ta(═NSiMe3)(bipy0) (16), (2,6-iPr2C6H3O)3Ta(═N2CPh2)(bipy0) (17); σ2-enediamide (2,6-iPr2C6H3O)3Ta(η2-N,N′-p-MeC6H4-DAD) (18); metallacyclopropenes (2,6-iPr2C6H3O)3Ta(η2-C2Ph2) (19) (2,6-iPr2C6H3O)3Ta[η2-C(Ph)═C(C≡CPh)](bipy0) (20) are formed two-electron process,

Язык: Английский

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The literature of heterocyclic chemistry, part XXII, 2022

Advances in heterocyclic chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Язык: Английский

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Advances in Transition Metal-Catalyzed Hydroamination of Strained Ring Systems: A Comprehensive Review

Tetrahedron, Год журнала: 2025, Номер unknown, С. 134652 - 134652

Опубликована: Апрель 1, 2025

Язык: Английский

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Regioselective Hydroaminoalkylation with Silylated Alkenes for β-Amino Acid Synthesis

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

Опубликована: Апрель 8, 2025

Catalyst and substrate steric electronic features that influence regioselectivity in hydroaminoalkylation were leveraged to develop a synthetic approach for the selective synthesis of β-amino acids. An situ generated tantalum-ureate catalyst was used prepare 18 γ-silylated amines up 93% yield from internal silylated alkenes. β-Amino silane regioisomer production rarely observed, making this work one few examples highly regioselective with unsymmetric These γ-amino silanes converted alcohols modified Tamao-Fleming oxidation strategy followed by two additional steps acids, including key fragment anticancer drug candidate Ipatasertib.

Язык: Английский

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Mechanism and Origin of Site Selectivity and Regioselectivity of Scandium-Catalyzed Benzylic C–H Alkylation of Tertiary Anilines with Alkenes

Inorganic Chemistry, Год журнала: 2023, Номер 62(2), С. 979 - 988

Опубликована: Янв. 5, 2023

Benzylic C(sp3)-H alkylation of tertiary anilines with alkenes by an anilido-oxazoline-ligated scandium alkyl catalyst was recently reported C-H site selectivity and alkene-dependent regioselectivity. Revealing the mechanism origin is undoubtedly great importance for understanding experimental observations developing new reactions. Herein, density functional theory (DFT) calculations have been carried out on model reaction Sc-catalyzed benzylic N,N-dimethyl-o-toluidine allylbenzene. The generally undergoes generation active species, alkene insertion, protonation steps. difference distortion energy aniline moiety in transition states, which related to ring size forming metallacycles, accounts activation. activation possessing less strained five-membered metallacycle compared ortho-C(sp2)-H α-methyl results observed experimentally. Both steric electronic factors are responsible 1,2-insertion regioselectivity alkyl-substituted alkenes, while control 2,1-insertion manner vinylsilanes. analysis original substrates further strengthens These help us obtain mechanistic expected be conducive development functionalization

Язык: Английский

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Applications of Vanadium, Niobium, and Tantalum Complexes in Organic and Inorganic Synthesis

ACS Organic & Inorganic Au, Год журнала: 2022, Номер 3(2), С. 74 - 91

Опубликована: Дек. 30, 2022

Organometallic catalysis is a powerful strategy in chemical synthesis, especially with the cheap and low toxic metals based on green chemistry principle. Thus, selection of metal particularly important to plan relevant applicable processes. The group VB have been subject exciting significant advances both organic inorganic synthesis. In this Review, we summarized some reports from recent decades, which are about development utilized various types reactions, such as oxidation, reduction, alkylation, dealkylation, polymerization, aromatization, protein practical water splitting.

Язык: Английский

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