5084-80-0Relevant articles and documents
A new polymorph of tri(p-tolyl)boroxine
Haberecht, Monika C.,Bolte, Michael,Wagner, Matthias,Lerner, Hans-Wolfram
, p. 657 - 665 (2005)
A new orthorhombic polymorph of tri(p-tolyl)boroxine (Pmn21) with relatively short intermolecular B-O distances of 3.321 A was crystallized from CDCl3 at ambient temperature. The crystal structure of the orthorhombic polymorph of tri
Synthesis of borophosphonate cage compounds: Influence of substituent and concentration effects on product distribution in condensation reactions of aryl phosphonic acids and boronic acids
Liu, Qian,Contrella, Nathan D.,Filatov, Alexander S.,Jordan, Richard F.
, p. 254 - 262 (2015)
Aryl borophosphonate cage compounds [ArPO3BAr′]n with n = 4 or 6 were synthesized by condensation reactions of ArP(O)(OH)2 and Ar′B(OH)2. (3,5-tBu2-Ph)P(O)(OH)2 (1) reacts with a
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.
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.