1143018-83-0Relevant articles and documents
Unlocking the catalytic potential of tris(3,4,5-trifluorophenyl)borane with microwave irradiation
Carden, Jamie L.,Gierlichs, Lukas J.,Wass, Duncan F.,Browne, Duncan L.,Melen, Rebecca L.
, p. 318 - 321 (2019)
The catalytic activity of tris(3,4,5-trifluorophenyl)borane has been explored in the 1,2-hydroboration reactions of unsaturated substrates. Under conventional conditions, the borane was found to be active only in the hydroboration of aldehyde, ketone and imine substrates, with alkenes and alkynes not being reduced effectively. The use of microwave irradiation on the other hand has permitted alkenes and alkynes to be hydroborated in good yields.
Metal–Ligand Cooperativity of the Calix[4]pyrrolato Aluminate: Triggerable C?C Bond Formation and Rate Control in Catalysis
Ebner, Fabian,Greb, Lutz,Sigmund, Lukas Maximilian
, p. 17118 - 17124 (2020)
Metal-ligand cooperativity (MLC) had a remarkable impact on transition metal chemistry and catalysis. By use of the calix[4]pyrrolato aluminate, [1]?, which features a square-planar AlIII, we transfer this concept into the p-block and fully elucidate its mechanisms by experiment and theory. Complementary to transition metal-based MLC (aromatization upon substrate binding), substrate binding in [1]? occurs by dearomatization of the ligand. The aluminate trapps carbonyls by the formation of C?C and Al?O bonds, but the products maintain full reversibility and outstanding dynamic exchange rates. Remarkably, the C?C bonds can be formed or cleaved by the addition or removal of lithium cations, permitting unprecedented control over the system's constitutional state. Moreover, the metal-ligand cooperative substrate interaction allows to twist the kinetics of catalytic hydroboration reactions in a unique sense. Ultimately, this work describes the evolution of an anti-van't Hoff/Le Bel species from their being as a structural curiosity to their application as a reagent and catalyst.
Synthesis and characterization of rare-earth metallate amido complexes bearing the 2-amidate-functionalized indolyl ligand and their application in the hydroboration of esters with pinacolborane
Bao, Qin,Gao, Jianjian,Hong, Dongjing,Mu, Xiaolong,Song, Lulu,Wang, Shaowu,Wei, Yun,Zhou, Shuangliu,Zhu, Xiancui
, p. 2953 - 2961 (2022/02/21)
The reactions of 2-amidate-functionalized indolyl proligand 2-(2,6-iPr2C6H3NHCO)C8H5NH (H2L) with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 were studied leading to the synthesis and characterization of a series of novel discrete trinuclear rare-earth metallate amido complexes containing the anion [{η1:(μ2-η1:η1):η1-LREN(SiMe3)2}3(μ3-Cl)]? and cation Li+(THF)4 (RE = Y(1a), Nd (1b), Sm (1c), Gd (1d), Dy (1e), Er (1f), and Yb (1g)) in good yields by silylamine elimination. All of the complexes were characterized by spectroscopic methods, elemental analyses and single-crystal X-ray diffraction, and complexes 1a and 1c were additionally characterized by NMR spectroscopy. As proof of principle of their activity, these complexes were used as precatalysts for the hydroboration of esters using HBpin as the hydride source displaying high activity under neat and room temperature conditions. As a result, the ligand, ionic and multinuclear cooperative effects on catalytic activity were observed.
Catalytic Hydroboration of Esters by Versatile Thorium and Uranium Amide Complexes
Makarov, Konstantin,Kaushansky, Alexander,Eisen, Moris S.
, p. 273 - 284 (2022/01/03)
The challenging hydroboration of esters is achieved using simple uranium and thorium amides, U[N(SiMe3)2]3 and [(Me3Si)2N]2An[κ2-(N,C)-CH2Si(CH3)2N(SiMe3)] (An = Th or U) acting as precatalysts in the reaction with pinacolborane (HBpin). All three complexes showed impressive catalytic activities, reaching excellent yields. A large scope of esters was investigated including aliphatic, aromatic, and heterocyclic esters that were transformed cleanly to the corresponding hydroborated alcohols, which readily hydrolyzed to the free alcohols. Moreover, the actinide catalysts demonstrated unexpected high functional tolerance toward nitro, halide, cyano, and heteroaromatic functional groups. The reaction exhibited excellent selectivity toward the ester when additional double and triple unsaturated C-C bonds were present. Lactones and poly caprolactone have been successfully cleaved to the monomeric units, showing a great promise toward polymer degradation and recycling. Detailed kinetic studies are provided in order to determine the rate dependence on the concentration of catalyst, HBpin, and ester. A plausible mechanism is proposed based on stoichiometric reactions, DFT calculations, thermodynamic measurements, and deuterium-labeling studies.
