Solid‐State Structures of Primary Long‐Chain Alkylamine Borane Adducts – Synthesis, Properties and Computational Analysis DOI Creative Commons
Kevin Turani‐I‐Belloto, María‐José Valero‐Pedraza,

Eddy Petit

et al.

ChemistrySelect, Journal Year: 2022, Volume and Issue: 7(43)

Published: Nov. 16, 2022

Abstract Two new members of the amine boranes family are hexadecylamine borane C 16 H 33 NH 2 BH 3 (C16AB) and octadecylamine 18 35 (C18AB). They easily synthesized by reaction corresponding amines with dimethyl sulfide. Both white solids; they crystalline isostructural (monoclinic, s.g. P2 1 /a (No. 14)). Their successful synthesis has been verified molecular (FTIR, Raman, NMR) structural analyses as well computational calculations (e. g. Mulliken charges). These have also pointed out existence dihydrogen bonds between δ+ one molecule δ− another molecule. The thermal stability C16AB C18AB was studied. solids melts at 70–80 °C; 100 ca. 210 °C dehydrogenate while releasing 1.1‐1.4 wt% pure ; and, above °C, decompose in high extent. All these findings may open way to future works on self‐assembly, advanced materials hydrogen storage. This is discussed hereafter.

Language: Английский

Selective [2σ + 2σ] Cycloaddition Enabled by Boronyl Radical Catalysis: Synthesis of Highly Substituted Bicyclo[3.1.1]heptanes DOI

Tao Yu,

Jinbo Yang, Zhijun Wang

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(7), P. 4304 - 4310

Published: Feb. 10, 2023

In contrast to the traditional and widely-used cycloaddition reactions involving at least a π bond component, [2σ + 2σ] radical between bicyclo[1.1.0]butanes (BCBs) cyclopropyl ketones has been developed provide modular, concise, atom-economical synthetic route substituted bicyclo[3.1.1]heptane (BCH) derivatives that are 3D bioisosteres of benzenes core skeleton number terpene natural products. The reaction was catalyzed by combination simple tetraalkoxydiboron(4) compound B2pin2 3-pentyl isonicotinate. broad substrate scope demonstrated synthesizing series new highly functionalized BCHs with up six substituents on 99% isolated yield. Computational mechanistic investigations supported pyridine-assisted boronyl catalytic cycle.

Language: Английский

Citations

124
Difluoromethylation of Unactivated Alkenes Using Freon-22 through Tertiary Amine-Borane-Triggered Halogen Atom Transfer DOI
Zhi‐Qi Zhang,

Yue‐Qian Sang,

Cheng‐Qiang Wang

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(31), P. 14288 - 14296

Published: July 27, 2022

The application of abundant and inexpensive fluorine feedstock sources to synthesize fluorinated compounds is an appealing yet underexplored strategy. Here, we report a photocatalytic radical hydrodifluoromethylation unactivated alkenes with industrial chemical, chlorodifluoromethane (ClCF2H, Freon-22). This protocol realized by merging tertiary amine-ligated boryl radical-induced halogen atom transfer (XAT) organophotoredox catalysis under blue light irradiation. A broad scope readily accessible featuring variety functional groups drug natural product moieties could be selectively difluoromethylated good efficiency in metal-free manner. Combined experimental computational studies suggest that the key XAT process ClCF2H both thermodynamically kinetically favored over hydrogen pathway owing formation strong boron–chlorine (B–Cl) bond low-lying antibonding orbital carbon–chlorine (C–Cl) bond.

Language: Английский

Citations

97
Photoinduced Halogen-Atom Transfer by N-Heterocyclic Carbene-Ligated Boryl Radicals for C(sp3)–C(sp3) Bond Formation DOI Creative Commons
Ting Wan, Luca Capaldo, Davide Ravelli

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 145(2), P. 991 - 999

Published: Dec. 30, 2022

Herein, we present a comprehensive study on the use of N-heterocyclic carbene (NHC)-ligated boryl radicals to enable C(sp3)–C(sp3) bond formation under visible-light irradiation via Halogen-Atom Transfer (XAT). The methodology relies an acridinium dye generate boron-centered from corresponding NHC-ligated boranes single-electron transfer (SET) and deprotonation. These subsequently engage with alkyl halides in XAT step, delivering desired nucleophilic radicals. strategy is very mild accommodates broad scope halides, including medicinally relevant compounds biologically active molecules. key role operative reaction mechanism has been elucidated through combination experimental, spectroscopic, computational studies. This stands as significant advancement chemistry radicals, which had long restricted radical reductions, enabling C–C photoredox conditions.

Language: Английский

Citations

54
Recent Advances in C–H Functionalisation through Indirect Hydrogen Atom Transfer DOI Creative Commons
Filip S. Meger, John A. Murphy

Molecules, Journal Year: 2023, Volume and Issue: 28(16), P. 6127 - 6127

Published: Aug. 18, 2023

The functionalisation of C–H bonds has been an enormous achievement in synthetic methodology, enabling new retrosynthetic disconnections and affording simple equivalents for synthons. Hydrogen atom transfer (HAT) is a key method forming alkyl radicals from substrates. Classic reactions, including the Barton nitrite ester reaction Hofmann–Löffler–Freytag reaction, among others, provided early examples HAT. However, recent developments photoredox catalysis electrochemistry have made HAT powerful tool capable introducing wide range functional groups into bonds. Moreover, greater mechanistic insights stimulated development increasingly site-selective protocols. Site-selectivity can be achieved through tuning electron density at certain using additives, judicious choice reagent, solvent system. Herein, we describe latest methods functionalizing C–H/Si–H/Ge–H indirect between 2018–2023, as well critical discussion reagents, aspects, substrate scopes, background contexts

Language: Английский

Citations

29
Halogen Atom Transfer-Induced Homolysis of C–F Bonds by the Excited-State Boryl Radical DOI

Jangwoo Koo,

Weonjeong Kim, Byung Hak Jhun

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(33), P. 22874 - 22880

Published: Aug. 2, 2024

A novel reactivity toward C-F bond functionalization has been developed, which could be designated as fluorine atom transfer (FAT). photoexcited state of an

Language: Английский

Citations

11
Dearomative 1,4-Difunctionalization of Non-Activated Arenes Enabled by Boryl Radical-Mediated Halogen-Atom Transfer DOI
Chengliang Deng, Hao Wu,

Sheng Li

et al.

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 1294 - 1304

Published: Jan. 7, 2025

Given the widespread presence of spirocyclic scaffolds in natural products and pharmacologically relevant synthetic compounds, development efficient methodologies for their construction holds great importance medicinal chemistry pharmaceutical research. In this study, a general photochemical dearomative spirocyclization nonactivated arenes has been established. The key to method lies ability amine-borane radicals activate aryl bromides iodides via halogen-atom transfer, thereby allowing conversion halides into corresponding subsequent chemodivergent transformations. remarkable compatibility versatility 1,4-difunctionalization is showed by rapid assembly structurally diverse 1,4-cyclohexadiene-based spirocycles incorporating oxindole, indoline, or dihydrobenzofuran subunits. Moreover, potential utility protocol exemplified formal total synthesis vasopressin V2 receptor antagonist Satavaptan.

Language: Английский

Citations

1
Photocatalytic [3 + 2]-annulation via sodium tetraarylborate: a fundamental approach for synthesizing 1,4,2-diazaborole analogs DOI Creative Commons

Hao-Ni Qin,

Haowen Jiang, Yi Zhao

et al.

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Nitriles stabilize neutral diarylboryl radicals, generating the RCN-BAr 2 complex, an efficient boron-nitrogen synthon that reacts with imines and olefins for photocatalytic synthesis of boron–nitrogen heterocycles, such as 1,4,2-diazaboroles.

Language: Английский

Citations

1
Chlorine-radical-mediated C–H oxygenation reaction under light irradiation DOI Creative Commons
Yuki Itabashi, Haruyasu Asahara, Kei Ohkubo

et al.

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(49), P. 7506 - 7517

Published: Jan. 1, 2023

This feature article summarizes the C–H oxygenation reaction involving chlorine radicals generated by light irradiation.

Language: Английский

Citations

19
Photocatalytic Boryl Radicals Triggered Sequential B─N/C─N Bond Formation to Assemble Boron‐Handled Pyrazoles DOI Creative Commons
Yang Xie, Ruilong Zhang,

Ze‐Le Chen

et al.

Advanced Science, Journal Year: 2023, Volume and Issue: 11(3)

Published: Nov. 29, 2023

Abstract Vinyldiazo compounds are one of the most important synthons in construction a cyclic ring. Most photochemical transformations vinyldiazo mainly focusing on utilization their C═C bond site, while reactions taking place at terminal nitrogen atom largely unexplored. Herein, photocatalytic cascade radical cyclization LBRs with reagents through sequential B─N/C─N formation is described. The reaction starts addition (Lewis base–boryl radicals) diazo followed by intramolecular to access wide range boron‐handled pyrazoles good excellent yields. Control experiments, together detailed mechanism studies well explain observed reactivity. Further demonstrate utility this approach for applications pharmaceutical and agrochemical research.

Language: Английский

Citations

17
Photoinduced Intermolecular Radical Hydroalkylation of Olefins via Ligated Boryl Radicals-Mediated Halogen Atom Transfer DOI Creative Commons

Ting Wan,

Łukasz W. Ciszewski, Davide Ravelli

et al.

Organic Letters, Journal Year: 2024, Volume and Issue: 26(27), P. 5839 - 5843

Published: July 1, 2024

Light-mediated Halogen-Atom Transfer (XAT) has become a significant methodology in contemporary synthesis. Unlike α-aminoalkyl and silyl radicals, ligated boryl radicals (LBRs) have not been extensively explored as halogen atom abstractors. In this study, we introduce NHC-ligated boranes optimal radical chain carriers for the intermolecular reductive hydroalkylation hydroarylation of electron-deficient olefins by using direct UV-A light irradiation. DFT analysis allowed us to rationalize critical role NHC ligand facilitating efficient propagation.

Language: Английский

Citations

8