- 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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- 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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- Direct Amidation of N-Boc- and N-Cbz-Protected Amines via Rhodium-Catalyzed Coupling of Arylboroxines and Carbamates
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N-Boc- and N-Cbz-protected amines are directly converted into amides by a novel rhodium-catalyzed coupling of arylboroxines and carbamates, replacing the traditional two-step deprotection-condensation sequence. Both protected anilines and aliphatic amines are efficiently transformed into a wide variety of secondary benzamides, including sterically hindered and electron-deficient amides, as well as in the presence of acid-labile and reducible functional groups.
- Lim, Diane S. W.,Lew, Tedrick T. S.,Zhang, Yugen
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supporting information
p. 6054 - 6057
(2016/01/09)
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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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- Novel rhodamine dyes via suzuki coupling of xanthone triflates with arylboroxins
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Novel rhodamine dyes were prepared from xanthone precursors in a 'one-pot' procedure via reaction of the xanthone with trifluoromethanesulfonic anhydride followed by Pd-mediated Suzuki coupling between the xanthone triflate and an arylboroxin. Rhodamines with 9-(3- or 4-carboxyphenyl) and 9-(3-nitrophenyl) substituents were prepared by this procedure. The procedure also works well with thio- and selenoxanthones, but not with telluroxanthones. Georg Thieme verlag Stuttgart.
- Calitree, Brandon D.,Detty, Michael R.
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scheme or table
p. 89 - 92
(2010/07/16)
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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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- Arylation and vinylation of α-diazocarbonyl compounds with boroxines
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An alternative approach for α-arylation and α-vinylation of carbonyl compounds is described: reaction between aryl-or vinylboroxines with α-diazocarbonyl compounds leads to the formation of α-arylated or α-vinylated carbonyl compounds under mild conditions.
- Peng, Cheng,Zhang, Wei,Yan, Guobing,Wang, Jianbo
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supporting information; experimental part
p. 1667 - 1670
(2009/08/07)
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- Synthetic and X-ray diffraction studies of borosiloxane cages [R′Si(ORBO)3SiR′] and the adducts of [ButSi{O(PhB)O}3SiBut] with pyridine or N,N,N′,N′-tetramethylethylenediamine
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Eleven borosiloxane [R′Si(ORBO)3SiR′] compounds where R′ = But and R = Ph (1), 4-PhC6H4 (2), 4-ButC6H4 (3), 3-NO2C6H4 (4), 4-CH(O)C6H4 (5), CpFeC5H4 (6), 4-C(O)CH3C6H4 (7), 4-ClC6H4 (8), 2,4-F2C6H3 (9), and R′ = cyclo-C6H11 and R = Ph (10), and 4-BrC6H4 (11) have been synthesized and characterized by spectroscopic (IR, NMR), mass spectrometric and, for compounds where R′ = But and R = 4-PhC6H4 (2), 4-ButC6H4 (3), 3-NO2C6H4 (4), CpFeC5H4 (6) and 2,4-F2C6H3 (9), X-ray diffraction studies. These compounds contain trigonal planar RBO2 and tetrahedral R′SiO3 units located around 11-atom "spherical" Si2O6B3 cores. The dimensions of the Si2O6B3 cores in compounds 2, 3, 4, 6 and 9 are remarkably similar. The reaction between [ButSi{O(PhB)O}3SiBut] (1), and excess pyridine yields the 1:1 adduct [ButSi{O(PhB)O}SiBut]. NC5H5 (12) while the reaction between 1 and N,N,N′,N′-tetramethylethylenediamine in equimolar amounts affords a 2:1 borosiloxane:amine adduct [ButSi{O(PhB)O}3SiBut]2 · Me2NCH2CH2NMe2 (13). Compounds 12 and 13 were characterised with IR and (1H, 13C and11B) NMR spectroscopies and the structure of the pyridine complex 12 was determined with X-ray techniques.
- Ferguson, George,Lawrence, Simon E.,Neville, Lorraine A.,O'Leary, Brian J.,Spalding, Trevor R.
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p. 2482 - 2492
(2008/10/09)
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