7294-51-1Relevant articles and documents
Nickel(II)-Catalyzed Addition of Aryl and Heteroaryl Boroxines to the Sulfinylamine Reagent TrNSO: The Catalytic Synthesis of Sulfinamides, Sulfonimidamides, and Primary Sulfonamides
Lo, Pui Kin Tony,Willis, Michael C.
supporting information, p. 15576 - 15581 (2021/10/02)
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
Copper-Catalyzed Asymmetric Arylation of N-Heteroaryl Aldimines: Elementary Step of a 1,4-Insertion
Wu, Chunlin,Qin, Xurong,Moeljadi, Adhitya Mangala Putra,Hirao, Hajime,Zhou, Jianrong Steve
supporting information, p. 2705 - 2709 (2019/02/06)
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.
Copper-mediated anomeric: O -arylation with organoboron reagents
Dimakos, Victoria,Liu, Jacklyn J. W.,Ge, Zhenlu,Taylor, Mark S.
supporting information, p. 5671 - 5674 (2019/06/18)
Copper-mediated couplings of arylboroxines with glycosyl hemiacetals furnish O-aryl glycosides via Csp2-O bond formation. The method enables the anomeric O-arylation of protected pyranose and furanose derivatives, and is tolerant of functionalized arylboroxine partners. Whereas mixtures of anomers are formed from glucopyranose, galactopyranose and arabinofuranose hemiacetals, the α-anomer is generated selectively from mannopyranose and mannofuranose-derived substrates.
Kinetics and Mechanism of the Palladium-Catalyzed Oxidative Arylating Carbocyclization of Allenynes
Bartholomeyzik, Teresa,Pendrill, Robert,Lihammar, Richard,Jiang, Tuo,Widmalm, G?ran,B?ckvall, Jan-E.
supporting information, p. 298 - 309 (2018/01/17)
Pd-catalyzed C-C bond-forming reactions under oxidative conditions constitute a class of important and widely used synthetic protocols. This Article describes a mechanistic investigation of the arylating carbocyclization of allenynes using boronic acids and focuses on the correlation between reaction conditions and product selectivity. Isotope effects confirm that either allenic or propargylic C-H activation occurs directly after substrate binding. With an excess of H2O, a triene product is selectively formed via allenic C-H activation. The latter C-H activation was found to be turnover-limiting and the reaction zeroth order in reactants as well as the oxidant. A dominant feature is continuous catalyst activation, which was shown to occur even in the absence of substrate. Smaller amounts of H2O lead to mixtures of triene and vinylallene products, where the latter is formed via propargylic C-H activation. The formation of triene occurs only in the presence of ArB(OH)2. Vinylallene, on the other hand, was shown to be formed by consumption of (ArBO)3 as a first-order reactant. Conditions with sub-stoichiometric BF3·OEt2 gave selectively the vinylallene product, and the reaction is first order in PhB(OH)2. Both C-H activation and transmetalation influence the reaction rate. However, with electron-deficient ArB(OH)2, C-H activation is turnover-limiting. It was difficult to establish the order of transmetalation vs C-H activation with certainty, but the results suggest that BF3·OEt2 promotes an early transmetalation. The catalytically active species were found to be dependent on the reaction conditions, and H2O is a crucial parameter in the control of selectivity.
Preparation of Quaternary Centers via Nickel-Catalyzed Suzuki-Miyaura Cross-Coupling of Tertiary Sulfones
Ariki, Zachary T.,Maekawa, Yuuki,Nambo, Masakazu,Crudden, Cathleen M.
supporting information, p. 78 - 81 (2018/01/17)
We describe the development of a nickel-catalyzed Suzuki-Miyaura cross-coupling of tertiary benzylic and allylic sulfones with arylboroxines. A variety of tertiary sulfones, which can easily be prepared via a deprotonation-alkylation route, were reacted to afford symmetric and unsymmetric quaternary products in good yields. We highlight the use of either BrettPhos or Doyle's phosphines as effective ligands for these challenging desulfonative coupling reactions. The utility of this methodology was demonstrated in the concise synthesis of a vitamin D receptor modulator analogue.
Rhodium-Catalyzed Enantioposition-Selective Hydroarylation of Divinylphosphine Oxides with Aryl Boroxines
Wang, Zhe,Hayashi, Tamio
supporting information, p. 1702 - 1706 (2018/02/06)
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.
Highly Enantioselective Ferrocenyl Palladacycle-Acetate Catalysed Arylation of Aldimines and Ketimines with Arylboroxines
Schrapel, Carmen,Frey, Wolfgang,Garnier, Delphine,Peters, René
supporting information, p. 2448 - 2460 (2017/02/23)
Benzylic N-substituted stereocenters constitute a frequent structural motif in drugs. Their highly enantioselective generation is hence of technical importance. An attractive strategy is the arylation of imines with organoboron reagents. Chiral Rh complexes have reached a high level of productivity for this reaction type. In this article we describe that an electron rich PdIIcatalyst also performs well in the arylation of aldimines, comparable to the best Rh catalysts. The ferrocenyl palladacycle-acetate catalyst allows for a broad substrate scope and very high enantioselectivities. Commonly observed side reactions like aryl–aryl homocouplings and imine hydrolysis could be blocked. Mechanistic studies implicate that a) the acetate ligand is crucial for transmetallation, b) the active catalyst is most likely a palladacycle-OAc monomer, c) the rate limiting step is probably the product release. By added KOAc the arylation could also be applied to ketimines.
Unveiling the role of boroxines in metal-free carbon-carbon homologations using diazo compounds and boronic acids
Bomio, Claudio,Kabeshov, Mikhail A.,Lit, Arthur R.,Lau, Shing-Hing,Ehlert, Janna,Battilocchio, Claudio,Ley, Steven V.
, p. 6071 - 6075 (2017/08/29)
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.
Palladium(II)-Catalyzed Enantioselective Synthesis of α-(Trifluoromethyl)arylmethylamines
Johnson, Thomas,Luo, Bo,Lautens, Mark
, p. 4923 - 4930 (2016/07/06)
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.
Rhodium-Catalyzed Asymmetric Arylation/Defluorination of 1-(Trifluoromethyl)alkenes Forming Enantioenriched 1,1-Difluoroalkenes
Huang, Yinhua,Hayashi, Tamio
supporting information, p. 12340 - 12343 (2016/10/07)
The reaction of 1-(trifluoromethyl)alkenes (CF3CH=CHR) with arylboroxines (ArBO)3 in the presence of a chiral diene-rhodium catalyst gave high yields of chiral 1,1-difluoroalkenes (CF2=CHC?HArR) with high enantioselectivity (≥95% ee). The reaction is assumed to proceed through β-fluoride elimination of a β,β,β-trifluoroalkylrhodium intermediate that is generated by arylrhodation of the 1-(trifluoromethyl)alkene.
