- Nickel(II)-Catalyzed Addition of Aryl and Heteroaryl Boroxines to the Sulfinylamine Reagent TrNSO: The Catalytic Synthesis of Sulfinamides, Sulfonimidamides, and Primary Sulfonamides
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We report a redox-neutral Ni(II)-catalyzed addition of (hetero)aryl boroxines to N-sulfinyltritylamine (TrNSO). The reactions use a catalyst generated from the combination of commercial, air-stable NiCl2·(glyme) and a commercially available bipyridine lig
- Lo, Pui Kin Tony,Willis, Michael C.
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supporting information
p. 15576 - 15581
(2021/10/02)
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- Copper-Catalyzed Asymmetric Arylation of N-Heteroaryl Aldimines: Elementary Step of a 1,4-Insertion
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Copper complexes of monodentate phosphoramidites efficiently promote asymmetric arylation of N-azaaryl aldimines with arylboroxines. DFT calculations and experiments support an elementary step of 1,4-insertion in the reaction pathway, a step in which an aryl-copper species adds directly across four atoms of C=N?C=N in the N-azaaryl aldimines.
- Wu, Chunlin,Qin, Xurong,Moeljadi, Adhitya Mangala Putra,Hirao, Hajime,Zhou, Jianrong Steve
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supporting information
p. 2705 - 2709
(2019/02/06)
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- Rhodium-Catalyzed Enantioposition-Selective Hydroarylation of Divinylphosphine Oxides with Aryl Boroxines
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The rhodium-catalyzed hydroarylation of divinylphosphine oxides (RP(O)(CH=CH2)2) with aryl boroxines ((ArBO)3) gives the corresponding monoarylation products (RP(O)(CH=CHAr)CH2CH3) in high yields. One of the two vinyl groups in the phosphine oxide undergoes oxidative arylation while the other one is reduced to an ethyl moiety. These reactions proceed with high selectivity in terms of the enantiotopic vinyl groups in the presence of (R)-DTBM-segphos/Rh to give the P-stereogenic monoarylation products with high enantioselectivity.
- Wang, Zhe,Hayashi, Tamio
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supporting information
p. 1702 - 1706
(2018/02/06)
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- Unveiling the role of boroxines in metal-free carbon-carbon homologations using diazo compounds and boronic acids
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By means of computational and experimental mechanistic studies the fundamental role of boroxines in the reaction between diazo compounds and boronic acids was elucidated. Consequently, a selective metal-free carbon-carbon homologation of aryl and vinyl boroxines using TMSCHN2, giving access to TMS-pinacol boronic ester products, was developed.
- Bomio, Claudio,Kabeshov, Mikhail A.,Lit, Arthur R.,Lau, Shing-Hing,Ehlert, Janna,Battilocchio, Claudio,Ley, Steven V.
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p. 6071 - 6075
(2017/08/29)
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- Palladium(II)-Catalyzed Enantioselective Synthesis of α-(Trifluoromethyl)arylmethylamines
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We describe a method for the synthesis of α-(trifluoromethyl)arylmethylamines that consists of the palladium(II)-catalyzed addition of arylboroxines to imines derived from trifluoroacetaldehyde. Palladium acetate is used as a catalyst with electron-neutral or electron-rich arylboroxines, and it was found that addition of an ammonium or silver salt was crucial to promote the reaction of electron-poor boroxines. With (S)-t-Bu-PyOX as the chiral ligand, this method delivers a variety of α-trifluoromethylated amines in 57-91% yield and with greater than 92% ee in most cases.
- Johnson, Thomas,Luo, Bo,Lautens, Mark
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p. 4923 - 4930
(2016/07/06)
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- Oxidative coupling of aryl boron reagents with sp3-carbon nucleophiles: The enolate chan–evans–lam reaction
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Reported is a versatile new oxidative method for the arylation of activated methylene species. Under mild reaction conditions (RT to 40°C), Cu(OTf)2mediates the selective coupling of functionalized aryl boron species with a variety of stabilized sp3-nucleophiles. Tertiary malonates and amido esters can be employed as substrates to generate quaternary centers. Complementing either traditional cross-coupling or SNAr protocols, the transformation is chemoselective in the presence of halogen electrophiles, including aryl bromides and iodides. Substrates bearing amide, sulfonyl, and phosphonyl groups, which are not amenable to coupling under mild Hurtley-type conditions, are suitable reaction partners.
- Moon, Patrick J.,Halperin, Heather M.,Lundgren, Rylan J.
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supporting information
p. 1894 - 1898
(2016/12/03)
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- Asymmetric Synthesis of Triarylmethanes by Rhodium-Catalyzed Enantioselective Arylation of Diarylmethylamines with Arylboroxines
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The reaction of racemic diarylmethylamines, (Ar1Ar2CHNR2), where Ar1 is substituted with a 2-hydroxy group, with arylboroxines (Ar3BO)3 in the presence of a chiral diene-rhodium catalyst gave high yields of chiral triarylmethanes (Ar1Ar2CH?Ar3) with high enantioselectivity (up to 97% ee). The reaction is assumed to proceed through o-quinone methide intermediates which undergo Rh-catalyzed asymmetric 1,4-addition of the arylboron reagents.
- Huang, Yinhua,Hayashi, Tamio
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supporting information
p. 7556 - 7559
(2015/07/01)
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- Vibrational properties of boroxine anhydride and boronate ester materials: Model systems for the diagnostic characterization of covalent organic frameworks
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The vibrational characteristics of 28 different boronic acid, boroxine anhydride, and boronate ester species have been systematically investigated using a combination of experimental infrared (IR) spectroscopy and computational modeling. IR bands characteristic to each boron-containing functionality have been categorized and assigned in conjunction with density functional theory (B3LYP/6-31G(d)), with the aim of better understanding and distinguishing the vibrational characteristics of covalent organic frameworks (COFs) built from boronic acids. In several cases, vibrational assignments differ from those previously reported in the literature on boronic acid-based COFs. Vibrations commonly regarded as diagnostic for one functionality are found in regions of the IR spectrum where other functionalities also show characteristic peaks. The collective experimental and computational results reveal that several alternative bands in the IR region can be used to more diagnostically distinguish between boronic acid, boroxine anhydride, and boronate ester species. The results presented herein provide the tools for straightforward characterization of boroxine anhydride and boronate ester species using IR spectroscopy. The results can be applied to additional theoretical studies of larger COF-like assemblies as well as the analysis of other boronic-acid-based materials.
- Smith, Merry K.,Northrop, Brian H.
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p. 3781 - 3795
(2014/07/08)
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- Enantioselective, nickel-catalyzed suzuki cross-coupling of quinolinium ions
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Quinolinium ions are engaged in an asymmetric, Ni-catalyzed Suzuki cross-coupling to yield 2-aryl- and 2-heteroaryl-1,2-dihydroquinolines. Key to the development of this method is the use of a Ni(II) precatalyst that activates without the need for strong reductants or high temperatures. The Ni-iminium activation mode is demonstrated as an exceptionally mild pathway to generate enantioenriched products from racemic starting materials.
- Shields, Jason D.,Ahneman, Derek T.,Graham, Thomas J. A.,Doyle, Abigail G.
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supporting information
p. 142 - 145
(2014/01/23)
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- Diastereoselective synthesis of vicinally bis(trifluoromethylated) alkylboron compounds through successive insertions of 2,2,2-trifluorodiazoethane
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The usefulness of embedded CF3 substituents within organic substructures necessitates the development of diverse methods for incorporating this functional group. A recently reported route to α-trifluoromethylated alkylboron compounds by an α-transfer mechanism has now been extended to the synthesis of unprecedented, vicinally ditrifluoromethylated alkylboron compounds in a diastereoselective fashion. The utility of these products is highlighted by conversion of the C-B bond into other functional groups.
- Molander, Gary A.,Ryu, Da Weon
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supporting information
p. 14181 - 14185
(2015/02/19)
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- Palladium(II)-catalyzed enantioselective synthesis of α- (trifluoromethyl)arylmethylamines
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Trifluoromethylacetaldimines, generated in situ from the corresponding N,O-acetals, undergo 1,2-addition of arylboroxines under palladium(II) catalysis to generate a variety of α-(trifluoromethyl)arylmethylamines with good to high enantioselectivity (up to 97% ee). The pyridine-oxazolidine (PyOX) class of ligands was found to be particularly suitable for this transformation, which proceeds without exclusion of ambient air and moisture.
- Johnson, Thomas,Lautens, Mark
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supporting information
p. 4043 - 4045
(2013/09/12)
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- Syntheses, characterization and reactivity of Lewis acid-base adducts based on B-N dative bonds
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Three Lewis acid-base adducts [(PhBO)3·2hmt] (1), [(PhBO)3-hmt-(PhBO)3] (2) and [{(F-Ph)BO} 3·hmt] (3) (hmt = hexamethylenetetramine) were prepared by the treatment of phenylboronic acid [PhB(OH)2] or
- Saha, Sudeshna,Kottalanka, Ravi Kumar,Panda, Tarun K.,Harms, Klaus,Dehnen, Stefanie,Nayek, Hari Pada
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p. 329 - 334
(2013/10/01)
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- Scalable synthesis of oxazolones from propargylic alcohols through multistep palladium(II) catalysis: β-selective oxidative heck coupling of cyclic sulfonyl enamides and aryl boroxines
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A whale of a scale: The title oxidative Heck coupling proceeded with unusual β selectivity to generate a variety of branched substituted oxazolones (see scheme; Ts=p-toluenesulfonyl). The three-step synthesis from readily available starting materials with a simple palladium catalyst and inexpensive reagents could be carried out in a single reaction vessel or scaled up for the preparation of large amounts of these amino acid precursors. Copyright
- Alamsetti, Santosh Kumar,Persson, Andreas K. A.,Jiang, Tuo,Baeckvall, Jan-E.
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supporting information
p. 13745 - 13750
(2014/01/06)
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- Rhodium(I)/diene-catalyzed addition reactions of arylborons with ketones
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Rh(I)/diene-catalyzed addition reactions of arylboroxines/arylboronic acids with unactivated ketones to form tertiary alcohols in good to excellent yields are described. By using C2-symmetric (3aR,6aR)-3,6-diaryl-1,3a,4,6a- tetrahydropentalenes as ligands, the asymmetric version of such an addition reaction, with up to 68% ee, was also realized.
- Liao, Yuan-Xi,Xing, Chun-Hui,Hu, Qiao-Sheng
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supporting information; experimental part
p. 1544 - 1547
(2012/06/05)
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- Mild and ligand-free Pd(II)-catalyzed conjugate additions to hindered γ-substituted cyclohexenones
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Ligand-free cationic Pd(II) catalyst with NaNO3 as an additive is a highly active catalytic system for conjugate additions to sterically hindered γ-substituted cyclohexenones. More challenging γγ- and βγ-substrates also react well to produce products with quaternary centers in good dr. The conjugate additions occur in a diastereoselective fashion under mild, practical and air-stable conditions, using readily available commercial reagents.
- Jordan-Hore, James A.,Sanderson, James N.,Lee, Ai-Lan
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supporting information; scheme or table
p. 2508 - 2511
(2012/07/03)
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- Solid-state 11B and 13C NMR, IR, and X-ray crystallographic characterization of selected arylboronic acids and their catechol cyclic esters
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Nine arylboronic acids, seven arylboronic catechol cyclic esters, and two trimeric arylboronic anhydrides (boroxines) are investigated using 11B solid-state NMR spectroscopy at three different magnetic field strengths (9.4, 11.7, and 21.1T). Through the analysis of spectra of static and magic-angle spinning samples, the 11B electric field gradient and chemical shift tensors are determined. The effects of relaxation anisotropy and nutation field strength on the 11B NMR line shapes are investigated. Infrared spectroscopy was also used to help identify peaks in the NMR spectra as being due to the anhydride form in some of the arylboronic acid samples. Seven new X-ray crystallographic structures are reported. Calculations of the 11B NMR parameters are performed using cluster model and periodic gauge-including projector-augmented wave (GIPAW) density functional theory (DFT) approaches, and the results are compared with the experimental values. Carbon-13 solid-state NMR experiments and spectral simulations are applied to determine the chemical shifts of the ipso carbons of the samples. One bond indirect 13C-11B spin-spin (J) coupling constants are also measured experimentally and compared with calculated values. The 11B/10B isotope effect on the 13C chemical shift of the ipso carbons of arylboronic acids and their catechol esters, as well as residual dipolar coupling, is discussed. Overall, this combined X-ray, NMR, IR, and computational study provides valuable new insights into the relationship between NMR parameters and the structure of boronic acids and esters. Copyright
- Oh, Se-Woung,Weiss, Joseph W. E.,Kerneghan, Phillip A.,Korobkov, Ilia,Maly, Kenneth E.,Bryce, David L.
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scheme or table
p. 388 - 401
(2012/08/13)
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- Rh-catalyzed addition of arylboroxines to cyclic N -(Isopropanesulfinyl) ketimines
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Arylboroxines, which are easily accessed by drying commercially available arylboronic acids, are added to N-(isopropanesulfinyl)ketimines derived from cyclohexanone, N-Boc-piperidin-4-one, and tetrahydropyran-4-one in high yields and with excellent functional group compatibility via rhodium catalysis. These results contrast with additions to the corresponding ketimines incorporating the larger N-tert-butanesulfinyl group, which give considerably lower yields. Efficient two-step preparation of racemic isopropanesulfinamide from inexpensive isopropyl disulfide and recycling of the isopropanesulfinyl group from the addition products are also described.
- Jung, Hyung Hoon,Buesking, Andrew W.,Ellman, Jonathan A.
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p. 9593 - 9600,8
(2012/12/12)
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- Rh-catalyzed addition of arylboroxines to cyclic N -(Isopropanesulfinyl) ketimines
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Arylboroxines, which are easily accessed by drying commercially available arylboronic acids, are added to N-(isopropanesulfinyl)ketimines derived from cyclohexanone, N-Boc-piperidin-4-one, and tetrahydropyran-4-one in high yields and with excellent functional group compatibility via rhodium catalysis. These results contrast with additions to the corresponding ketimines incorporating the larger N-tert-butanesulfinyl group, which give considerably lower yields. Efficient two-step preparation of racemic isopropanesulfinamide from inexpensive isopropyl disulfide and recycling of the isopropanesulfinyl group from the addition products are also described.
- Jung, Hyung Hoon,Buesking, Andrew W.,Ellman, Jonathan A.
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p. 9593 - 9600
(2013/01/15)
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- Bis-sulfamyl imines: Potent substrates for asymmetric additions of arylboroxines under rhodium catalysis
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Bis-sulfamyl imines are shown to be potentially ideal substrates for rhodium-catalysed asymmetric additions of arylboron nucleophiles as they show: (i) near perfect enantioselectivities (11 examples, 98-99+% ee), (ii) good to excellent diastereoselectivities (10-32:1 rac:meso), and (iii) high functional group tolerance in removal of the low molecular weight protecting group via mild heating in aqueous pyridine.
- Crampton, Rosemary,Woodward, Simon,Fox, Martin
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supporting information; experimental part
p. 903 - 906
(2011/06/19)
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- Highly functional group compatible Rh-catalyzed addition of arylboroxines to activated N-tert-butanesulfinyl ketimines
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The rhodium-catalyzed addition of readily accessible arylboroxines to N-tert-butanesulfinyl ketimines derived from oxetan-3-one, N-Boc-azetidin-3-one, and isatins proceeds in high yields with excellent functional group compatibility. Moreover, high diastereoselectivities are observed for the additions to the N-sulfinyl ketimines derived from isatins.
- Jung, Hyung Hoon,Buesking, Andrew W.,Ellman, Jonathan A.
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supporting information; experimental part
p. 3912 - 3915
(2011/09/16)
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- CuCl/bipyridine-catalyzed addition reactions of arylboroxines with aldehydes, α,β-unsaturated ketones, and N-tosyl aldimines
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CuCl/bipyridine-catalyzed addition reactions of arylboroxines with aldehydes and α,β-unsaturated ketones at elevated temperatures were described. By using the microwave energy, CuCl/bipyridine-catalyzed addition reactions of arylboroxines with aldimines were also realized.
- Liao, Yuan-Xi,Hu, Qiao-Sheng
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body text
p. 7602 - 7607
(2011/11/12)
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- Nickel-catalyzed efficient and practical Suzuki-Miyaura coupling of alkenyl and aryl carbamates with aryl boroxines
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(Figure Presented) Suzuki-Miyaura coupling of unactivated alkenyl carbamates Is described to construct polysubstituted olefins. The developed process is also suitable for heteroaromatic and even electron-rich aromatic carbamates.
- Xu, Li,Li, Bi-Jie,Wu, Zhen-Hua,Lu, Xing-Yu,Guan, Bing-Tao,Wang, Bi-Qin,Zhao, Ke-Qing,Shi, Zhang-Jie
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supporting information; experimental part
p. 884 - 887
(2010/04/29)
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- Chiral tetrafluorobenzobarrelenes as effective ligands for rhodium-catalyzed asymmetric 1,4-addition of arylboroxines to β,β-disubstituted α,β-unsaturated ketones
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(Chemical Equotion Present) Lock, Stock and Two Smoking Barrelenes: The rhodium-catalyzed 1,4-addition of readily available arylboronic acid anhydrides to simple β,β-disubstituted α,βunsaturated ketones creates quaternary carbon stereocenters with high enantiomeric excesses using a chiral tetrafluorobenzobarrelene ligand.
- Shintani, Ryo,Takeda, Momotaro,Nishimura, Takahiro,Hayashi, Tamio
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supporting information; experimental part
p. 3969 - 3971
(2010/09/03)
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- Construction of polysubstituted olefins through Ni-Catalyzed direct activation of Alkenyl C-O of substituted alkenyl acetates
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(Figure Presented) Reliable companion: For the first time cross-coupling between alkenyl acetates and arylboroxines/PhZnCl has been developed via Ni catalysis. Alkenyl acetates could be well-differ-entiated from aryl acetates (see scheme). This reliable method provides a convenient pathway to construct polysubstituted styrene derivatives.
- Sun, Chang-Liang,Yang, Wang,Xiao, Zhou,Wu, Zhen-Hua,Li, Bi-Jie,Guan, Bing-Tao,Shi, Zhang-Jie
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supporting information; body text
p. 5844 - 5847
(2010/09/03)
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- Hetero-arylboroxines: The first rational synthesis, X-ray crystallographic and computational analysis
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A novel series of hetero-arylboroxines were synthesized and structurally characterized by X-ray diffraction, NMR and computational analysis. The solid-state structures of the hetero-arylboroxines represent the first report of AB2-type hetero-arylboroxines.
- Iovine, Peter M.,Gyselbrecht, Charles R.,Perttu, Emily K.,Klick, Cole,Neuwelt, Alexander,Loera, Jason,DiPasquale, Antonio G.,Rheingold, Arnold L.,Kua, Jeremy
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supporting information; experimental part
p. 3791 - 3794
(2009/02/02)
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- High performance of a chiral diene-rhodium catalyst for the asymmetric 1,4-addition of arylboroxines to α,β-unsaturated ketones
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A rhodium complex coordinated with (S,S)-2,5-dibenzylbicyclo[2.2.2]octa-2, 5-diene (Bn-bod*) showed high catalytic activity and high enantioselectivity in the asymmetric 1,4-addition of arylboroxines to cyclic α,β-unsaturated ketones, 0.005-0.01 mol % of the catalyst giving high yields of the addition products with not lower than 94% ee. The turnover frequency of the catalyst is up to 1.4 × 104 h-1.
- Chen, Fu-Xue,Kina, Asato,Hayashi, Tamio
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p. 341 - 344
(2007/10/03)
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- Polyfluoroorganoboron-oxygen compounds. 1: Polyfluorinated aryl(dihydroxy)boranes and tri(aryl)boroxins
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A general preparative procedure for polyfluorinated aryl(dihydroxy)boranes C6H5-nFnB(OH)2 (n = 3 - 5) is described. Polyfluorinated aryl(dihydroxy)boranes are easily dehydrated to the corresponding tri(aryl)boroxins (C6H5-nFnBO)3 by thermal or chemical treatment. The property of the acids C6H5-nFnB(OH)2 to condensate depends on the number and on the position of the fluorine atoms in the aryl group. Examples of both classes of boron compounds were isolated as pure individuals and characterized by multinuclear NMR spectroscopy.
- Frohn,Adonin,Bardin,Starichenko
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p. 2827 - 2833
(2008/10/08)
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