149777-83-3Relevant articles and documents
Polyhedral Cu2O Crystals for Diverse Aryl Alkyne Hydroboration Reactions
Tsai, Hsin-Yi,Madasu, Mahesh,Huang, Michael H.
, p. 1300 - 1303 (2019)
Cu2O cubes, octahedra, and rhombic dodecahedra have been used to examine facet-dependent catalytic activity in aryl alkyne hydroboration reactions. Although the reaction can proceed by using ethanol or other alcohols as solvent, the use of 1,4-dioxane gave the best product yield. All particle shapes gave exclusively the E-product, but the rhombic dodecahedra exposing {110} surfaces were consistently far more reactive than the other particle morphologies. A product yield of 99 % was achieved by using Cu2O rhombic dodecahedra to catalyze the hydroboration of phenylacetylene at 60 °C for 5 h. The rhombic dodecahedra have been shown to catalyze a variety of substituted aryl alkynes, which demonstrates their potential as a versatile catalyst.
Aluminum Hydride Catalyzed Hydroboration of Alkynes
Bismuto, Alessandro,Thomas, Stephen P.,Cowley, Michael J.
, p. 15356 - 15359 (2016)
An aluminum-catalyzed hydroboration of alkynes using either the commercially available aluminum hydride DIBAL-H or bench-stable Et3Al?DABCO as the catalyst and H-Bpin as both the boron reagent and stoichiometric hydride source has been developed. Mechanistic studies revealed a unique mode of reactivity in which the reaction is proposed to proceed through hydroalumination and σ-bond metathesis between the resultant alkenyl aluminum species and HBpin, which acts to drive turnover of the catalytic cycle.
Photoswitchable metal-mediated catalysis: Remotely tuned alkene and alkyne hydroborations
Neilson, Bethany M.,Bielawski, Christopher W.
, p. 3121 - 3128 (2013)
A photochromic dithienylethene-annulated N-heterocyclic carbene (NHC)-Rh(I) complex was synthesized and found to undergo reversible electrocyclic ring closure upon alternate exposure to UV (λirr 313 nm) and visible (λirr >500 nm) radiation. Under ambient light, the Rh catalyst efficiently promoted the hydroboration of alkenes and alkynes with pinacolborane. However, upon UV irradiation to effect a photocyclization within the NHC ligand, the catalytic activity was reduced by up to an order of magnitude. The disparity in the rates was used to photoswitch the rates of a series of hydroboration reactions, thus demonstrating the first examples of photomodulating a transition-metal catalyst by tuning its electronic properties. The rate attenuation observed under UV irradiation was attributed to inhibition of the rate-determining reductive elimination step arising from a decrease in electron-donating ability of the photocyclized NHC ligated to the Rh center.
Zwitterion-Initiated Hydroboration of Alkynes and Styrene
Bismuto, Alessandro,Cowley, Michael J.,Thomas, Stephen P.
, p. 2382 - 2385 (2021)
The hydroboration of alkynes and styrene with HBpin has been developed using tris(pentaflurophenyl)borane (B(C6F5)3) as the initiator of catalysis. The hydroboration is proposed to be initiated by Lewis acid activation of the alkyne by (B(C6F5)3) to form a highly reactive zwitterionic species which subsequently react with HBpin to give the alkenyl boronic ester. This zwitterion has also showed potential to be a competent catalyst for the hydroboration of styrene. The zwitterionic intermediate is analogous to that proposed in the Piers borane-catalysed hydroboration and 1,1-carboboration of alkynes with B(C6F5)3. (Figure presented.).
Cyclic (Alkyl)(amino)carbene Ligands Enable Cu-Catalyzed Markovnikov Protoboration and Protosilylation of Terminal Alkynes: A Versatile Portal to Functionalized Alkenes**
Bertrand, Guy,Engle, Keary M.,Gao, Yang,Grotjahn, Douglas B.,Jazzar, Rodolphe,Junor, Glen P.,Kang, Taeho,Kendrick, Aaron,Yazdani, Sima
supporting information, p. 19871 - 19878 (2021/08/13)
Regioselective hydrofunctionalization of alkynes represents a straightforward route to access alkenyl boronate and silane building blocks. In previously reported catalytic systems, high selectivity is achieved with a limited scope of substrates and/or rea
Cobalt-Catalyzed Markovnikov-Type Selective Hydroboration of Terminal Alkynes
Chen, Jieping,Shen, Xuzhong,Lu, Zhan
supporting information, p. 690 - 694 (2020/11/30)
A cobalt-catalyzed Markovnikov-type hydroboration of terminal alkynes with HBpin to access α-alkenyl boronates with good regioselectivity and atom economy is reported. A new ligand has been developed for the cobalt hydride catalyst that has been used for a unique Markovnikov selective insertion of terminal alkynes into metal hydride bond. This operationally simple protocol exhibits excellent functional group tolerance to deliver valuable alkene derivatives.
