Chemistry - An Asian Journal, Journal Year: 2023, Volume and Issue: 18(23)
Published: Oct. 9, 2023
A sustainable and metal-free protocol has been described for the reduction of unprotected indoles. The catalytic system consists B(C6 F5 )3 THF as a Lewis acid-base pair that can activate B-H bond pincolborane (HBpin). encompasses broad substrate scope. Control experiments were conducted to understand possible intermediates involved during present protocol.
Language: Английский
Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(26)
Published: Feb. 14, 2024
Abstract This review provides a comprehensive overview of mono‐alkylation methodologies targeting crucial nitrogen moieties – amines, amides, and sulfonamides found in organic building blocks pharmaceuticals. Emphasizing the intersection chemical precision with drug discovery, central challenge addressed is achieving one‐pot mono‐selective short‐chain N‐alkylations (methylations, ethylations, n ‐propylations), preventing undesired overalkylation. Additionally, sustainable, safe, benign alternatives to traditional alkylating agents, including alcohols, carbon dioxide, carboxylic acids, nitriles, alkyl phosphates, quaternary ammonium salts, carbonates, are explored. review, categorized by nature agent, aids researchers selecting suitable methods for N‐alkylation.
Language: Английский
Citations
6
Organic & Biomolecular Chemistry, Journal Year: 2025, Volume and Issue: 23(10), P. 2400 - 2410
Published: Jan. 1, 2025
In this study, we present the first catalytic methodology for synthesizing N-methyl secondary amides via dehydrative condensation of hydroxycarboxylic acids with readily available and safe aqueous methylamine, employing diboronic acid anhydride (DBAA) as catalyst. DBAA catalysis can also be applied to direct amidations using ethylamine or dimethylamine. Moreover, demonstrate applicability system concise synthesis eight biologically active compounds containing β-amino alcohol motifs, including halostachine, synephrine, longimammine, phenylephrine, metanephrine, normacromerine, etilefrine, macromerine.
Language: Английский
Citations
0
Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown
Published: Feb. 17, 2025
Herein, we report the carbene-like activity of a nonisolable, highly ambiphilic cyclic (alkenyl)(amino)carbene (SMeCAenAC, 3), which is stabilized as [(SMeCAenAC)(H)N(SiMe3)2] (4). This protected form (4) stable in air and moisture. Compound 4 can be used carbene source through deamination upon heating to 130-140 °C. Moreover, density functional theory (DFT) calculations indicate that SMeCAenAC has smallest singlet-triplet gap (37.05 kcal/mol) narrow highest occupied molecule orbital (HOMO)-lowest unoccupied molecular (LUMO) (3.92 eV) among (alkyl)(amino)carbenes (CAACs). The precursor (3) synthesized on multigram scale with good yield. SMeCAenAC-coordinated copper complex showed excellent efficiency catalytic addition phenols electron-deficient olefins. study also highlights [SMeCAenAC-H]OTf for metal-free catalysis, property uniquely characteristic an carbene, even though formation free was not achieved.
Language: Английский
Citations
0
Organic Letters, Journal Year: 2025, Volume and Issue: unknown
Published: March 25, 2025
A new catalytic conversion type of nitro substrate with CO2 as a single-carbon source is presented, wherein great collection azaheterocycles generated by newly established iridium-catalyzed, copper-induced reductive system. This procedure handily employs poly(methylhydrosiloxane) (PMHS) the reductant to simultaneously realize dual reduction highest oxidation-state and units in one operation. Elaborate mechanistic studies illustrate essential role iridium catalyst reducing NO2 moiety well double functions copper additive subsequent formylation C-H cyclization steps.
Language: Английский
Citations
0
Organic Letters, Journal Year: 2025, Volume and Issue: unknown
Published: April 11, 2025
This study reports the catalytic N-methylation of NH-sulfoximines using carbon dioxide (CO2) under metal-free conditions. A mesoionic N-heterocyclic olefin (mNHO) was used as a catalyst for in presence 9-borabicyclo[3.3.1]nonane (9-BBN) mild process to convert various into N-methylsulfoximines. protocol also applicable synthesis 13C-labeled N-methylsulfoximines 13CO2. mechanistic cycle proposed by performing series control reactions and successfully characterizing active intermediates either single-crystal X-ray or NMR spectroscopic studies.
Language: Английский
Citations
0
Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown
Published: April 21, 2025
Stereogenic units are a critical source of molecular complexity, but their stereoselective formation via main group ambiphiles─which suitable for derivatizing wide scope functionalities─is largely unexplored. Herein, using chiral cyclic (alkyl)(amino)carbenes (ChiCAACs), we study stereoinduction during the oxidative addition E-H σ-bonds (E = C, N, O, Si, P). Through computational modeling, relationship between stereochemical outcome and mechanism is elucidated, providing insight into when why ChiCAACs exhibit excellent stereoselectivities. Altogether, these results demonstrate potential ambiphiles to generate stereogenic in highly controlled manner opening avenues applying "metal-like" reactivity metal-free asymmetric syntheses.
Language: Английский
Citations
0
Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(62)
Published: Aug. 15, 2024
Abstract The synthesis and reactivity of an air water stable Bicyclic (alkyl)(amino)carbene (BICAAC) stabilized phosphenium cation (1) is reported. Air are rare in the literature. Compound 1 obtained by reaction BICAAC with Ph 2 PCl THF followed anion exchange LiOTf. reduction oxidation yielded corresponding α‐radical phosphine species (2) oxide (3) respectively. All compounds well characterized single crystal X‐ray diffraction studies. Lewis acidity 3 determined conducting fluoride ion affinity experiments using UV‐Vis spectrophotometry multinuclei NMR spectroscopy. Compounds exhibited selective binding to but did not interact other halides (Cl − Br ). Quantum chemical calculations were performed understand structure nature bonding interactions these compounds, as comprehend specific over halide ions.
Language: Английский
Citations
3
ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(10), P. 8087 - 8095
Published: May 8, 2024
In this report, an unusual bond activation strategy has been demonstrated by BICAAC, which essentially emulates the behavior of a transition metal. The ambiphilic nature specific carbene facilitated simultaneous proton and hydride capture from alcohol molecule to carry out smooth dehydrogenation under mild conditions. route closely follows traditional metal–ligand bifunctional substrate. hydrogen extracted substrate becomes stored in carbon, unambiguously ascertained isolation intermediate its X-ray crystallographic characterization. Such event further interrogated detail deuterium-labeling experiment DFT computations substantiate critical role carbene's ambiphilicity. Additionally, delivered situ-generated olefinic completely mimic borrowing reaction organocatalytic fashion. Both rehydrogenation reactions have conducted single pot using BICAAC as catalyst that alkylates fluorene at 9-position series alcohols alkyl source. A thorough mechanistic sketch describes involvement radical for latter part reaction, overall bringing different outlook carbene-promoted small-molecule reactions.
Language: Английский
Citations
2
ChemCatChem, Journal Year: 2024, Volume and Issue: 16(21)
Published: July 16, 2024
Abstract Here we report on the use of formic acid as a green and safe reagent for N‐methylation primary amides in presence Pd/In 2 O 3 solid catalyst. No additive is needed are selectively N‐methylated good to excellent yields. The reaction operates through formylation/reduction pathway, leaving amide carbonyl untouched.
Language: Английский
Citations
1
Dalton Transactions, Journal Year: 2024, Volume and Issue: unknown
Published: Jan. 1, 2024
This review covers the synthesis, characterization, and reactivity of bicyclic(alkyl)(amino)carbenes (BICAACs) outlines diverse applications BICAACs in organometallic chemistry, metal-free catalysis, main-group chemistry.
Language: Английский
Citations
1