Chemical Communications, Journal Year: 2021, Volume and Issue: 57(13), P. 1655 - 1658
Published: Jan. 1, 2021
A
palladium-catalyzed
selective
B(3)–H
arylation
of
Language: Английский
Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(21), P. 4065 - 4079
Published: Oct. 24, 2021
ConspectusCarboranes are a class of polyhedral carbon-boron molecular clusters featuring three-dimensional aromaticity, which often considered as 3D analogues benzene. Their unique structural and electronic properties make them invaluable building blocks for applications ranging from functional materials to versatile ligands pharmaceuticals. Thus, selective functionalization carboranes has received tremendous research interest. In earlier days, the vast majority works in this area were focused on cage carbon via facile deprotonation CH, followed by reaction with electrophiles. On contrary, B-H activation is very challenging since 10 bonds o-carborane similar, how achieve desired transformation at specific boron vertex long-standing issue.As more electronegative than boron, property results different charges cage, follow order B(3,6)-H ≪ B(4,5,7,11)-H < B(8,10)-H B(9,12)-H. We thought that difference may trigger favorite interaction proper transition metal complex bond carborane, could be utilized solve selectivity issue. Accordingly, our strategy described follows: (1) electron-rich catalysts good most electron-deficient (connected both C-H vertices); (2) relatively B(8,9,10,12)-H (with no bonding either (3) directing-group-assisted catalysis appropriate only one vertex), whose lie middle range bonds. This been successfully applied laboratory other groups development series synthetic routes catalytic carborane resulting synthesis large number cage-boron-functionalized derivatives regioselective fashion. Subsequently, significant progress emerging made.In 2013 we reported tetrafluorination o-carboranes using an Pd(II) salt, [Pd(MeCN)4][BF4], catalyst. 2014 disclosed first example carboxy-directed alkenylation B(4) promoted Ir(III) 2017 presented Ir(I)-catalyzed diborylation also uncovered Pd-catalyzed asymmetric chiral-at-cage 2018. These proof-of-principle studies have greatly stimulated activities enabled catalysts. so far developed toolbox methods B-olefination, -arylation, -alkenylation, -alkynylation, -oxygenation, -sulfenylation, -borylation, -halogenation, -amination. recently expanded base catalysis. As field progresses, expect will invented, detailed Account promote these efforts.
Language: Английский
Citations
110
Bulletin of the Chemical Society of Japan, Journal Year: 2020, Volume and Issue: 94(3), P. 879 - 899
Published: Dec. 18, 2020
Abstract Carboranes are a class of carbon-boron molecular clusters, possessing extraordinary characteristics including three-dimensional aromaticity conjugated by σ-bonds, icosahedral geometry and inherent robustness. They finding growing applications as valuable building blocks in boron neutron capture therapy agents, pharmacophores, nanomaterials, optoelectronic, organometallic/coordination chemistry more. Therefore, the effective controlled functionalization carboranes has attracted enormous research interests, particularly regio- enantio-selective cage BH derivatization among ten chemically similar vertices o-carboranes. Only recent few years, significant progress been made transition metal catalyzed vertex-specific functionalization. This review summarizes advances this realm.
Language: Английский
Citations
77
Chemical Science, Journal Year: 2020, Volume and Issue: 11(39), P. 10764 - 10769
Published: Jan. 1, 2020
B–H: site-selective B(3,4)–H arylations were accomplished at room temperature by versatile palladium catalysis enabled weakly coordinating amides.
Language: Английский
Citations
55
Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown
Published: Sept. 13, 2024
The innovation of synthetic strategies for selective B-H functionalization is a pivotal objective in the realm boron cluster chemistry. However, precise, efficient, and rapid bond carboranes that distant from existing functional groups remains intractable owing to limited approaches site-selective control established methods. Herein, we report dative bonding activation strategy nonclassical remote site
Language: Английский
Citations
7
Chinese Journal of Chemistry, Journal Year: 2020, Volume and Issue: 38(4), P. 383 - 388
Published: Jan. 16, 2020
Summary of main observation and conclusion Ir‐catalyzed cascade dehydrogenative CH/BH BH/OH cross‐coupling carboranyl carboxylic acid with readily available benzoic has been achieved, leading to the facile synthesis previously unavailable carborano‐coumarin in a simple one‐pot process. Two cage B—H, one aryl C—H O—H bonds are activated construct efficiently new B—C B—O bonds. The cyclization can stop at first B—H/C—H step by tuning reaction conditions, resulting series α‐carboranyl carborane derivatives. Control experiments indicate that dehydrocoupling proceeds preferentially over B—H/O—H dehydrocoupling, both directing groups oxidants crucial for this reaction. An iridium(V) intermediate is proposed be involved catalytic cycle.
Language: Английский
Citations
40
Chemical Science, Journal Year: 2021, Volume and Issue: 12(47), P. 15563 - 15571
Published: Jan. 1, 2021
Metal-catalyzed selective mono-acylmethylation of pyridylcarboranes has been realized, which provides further utility to construct carborane-fused indoliziniums and quinoliziniums.
Language: Английский
Citations
35
Inorganic Chemistry, Journal Year: 2022, Volume and Issue: 61(13), P. 5326 - 5334
Published: March 21, 2022
The B(9)-H halogenation of o-carborane and m-carborane was achieved with excellent selectivities in hexafluoroisopropanol (HFIP) under simple reaction conditions: single reagent [trichloroisocyanuric acid (TCCA), tribromoisocyanuric (TBCA) or N-iodosuccinimide (NIS)], catalyst-free, air-/moisture-tolerant, convenient work-up. With this method, a variety 9-halogenated o-carboranes m-carboranes were obtained good to yields broad tolerance functional groups.
Language: Английский
Citations
28
Organic Letters, Journal Year: 2022, Volume and Issue: 24(6), P. 1318 - 1322
Published: Feb. 7, 2022
A highly efficient Ir-catalyzed regioselective cage B(4)-H acylmethylation of o-carboranyl acids using sulfoxonium ylides as alkylating regents has been developed, leading to the preparation a large class B(4)-acylmethylated o-carboranes in good excellent yields with broad substrate scope under redox neutral conditions. The -COOH moiety serves traceless directing group and controls regioselectivity monoselectivity.
Language: Английский
Citations
24
Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 26(22), P. 5037 - 5050
Published: Feb. 5, 2020
A facile approach to the synthesis of diaryl- and dialkyl-substituted monophosphino-o-carboranes by rhodium(I)-catalyzed phosphine-directed B3,6 -H activation has been developed for first time. Upon switching rhodium(I) palladium(II), C-arylated B6 -halogenated products were obtained using tBuOLi Li2 CO3 as base, respectively. These discoveries provide some simple efficient approaches modification monophosphino-o-carboranes.
Language: Английский
Citations
38
Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 26(32), P. 7212 - 7218
Published: Feb. 10, 2020
Abstract Iridium‐catalyzed formal alkyne hydroboration with cage B−H of o ‐carborane has been achieved, leading to the controlled synthesis a series 3,6‐[ trans ‐(AlkCH=CH)] 2 ‐ ‐carboranes (Alk=alkyl), 3‐ cis ‐(ArCH=CH)‐ (Ar=aryl), and ‐(ArCH=CH)‐6‐ ‐(AlkCH=CH)‐ in high yields excellent regio‐ very good – selectivity. The most electron‐deficient B(3,6)−H vertices favor oxidative addition on electron‐rich metal centers, which is responsible for regioselectivity. On other hand, configuration resultant olefinic units dominated by substituents. Alkyl groups lead ‐configuration whereas bulky aryl substitutions result ‐configuration.
Language: Английский
Citations
37