- Atomic-dispersed platinum anchored on porous alumina sheets as an efficient catalyst for diboration of alkynes
-
Atomic-dispersed Pt anchored on defect-rich porous alumina sheets (Pt/dp-Al2O3) was accessed via a wet impregnation combined with pyrolysis method. These nanosheets functionalized by atomic-dispersed Pt possess a high density of active sites, exhibiting an exceptional catalytic activity combined with cyclic performance in the diboration of alkynes. The selectivity and conversion yield could reach as high as 97% and 98%, respectively.
- Chen, Wenxing,Jiang, Zhuoli,Shang, Huishan,Zhang, Jiatao,Zhou, Danni
-
-
Read Online
- A general strategy to prepare atomically dispersed biomimetic catalysts based on host-guest chemistry
-
Herein, we report a general strategy based on host-guest interactions to fabricate atomically dispersed biomimetic catalysts, which were evaluated by diboration of phenylacetylene. The structure and function of these mimics are quite similar to those of enzymes, namely, the atomically dispersed metal serves as an active site, the external macromolecular structure plays a role as an enzyme catalytic pocket to stabilize the reaction intermediates and the interactions between the intermediates and functional groups near to the active site can reduce the reaction activation energy.
- Han, Xiao,Chen, Zheng,Chen, Wenxing,Lv, Chunlin,Ji, Yongjun,Li, Jing,Cheong, Weng-Chon,Lei, Xiaojuan,Peng, Qing,Chen, Chen,Wang, Dingsheng,Lian, Chao,Li, Yadong
-
supporting information
p. 1895 - 1898
(2021/03/01)
-
- Dehydrogenative Diboration of Alkynes Catalyzed by Ir/CO/tBuNC System
-
Catalytic dehydrogenative diboration (DHDB) of alkyne with HBpin was achieved using [Ir(COD)Cl]2 and other related Ir precursors under CO atmosphere. The selectivity for DHDB over hydroboration was higher in less polar solvents and under higher
- Lai, Qingheng,Ozerov, Oleg V.
-
-
- Base-catalyzed diborylation of alkynes: synthesis and applications of cis-1,2-bis(boryl)alkenes
-
An efficient, transition-metal free, and practical approach to cis-bis(boryl)alkenes from various alkynes was disclosed in the presence of a catalytic amount of K2CO3 under mild conditions. Meanwhile, tetrasubstituted alkenes and phenanthrene derivatives were readily constructed from the target diborylalkenes via Suzuki-Miyaura cross coupling.
- Kuang, Zhijie,Gao, Guoliang,Song, Qiuling
-
-
- Gold-nanoparticle-catalyzed mild diboration and indirect silaboration of alkynes without the use of silylboranes
-
Commercially available Au nanoparticles supported on TiO2 were used to catalyze the cis diboration of terminal and internal alkynes with bis(pinacolato)diboron. The products were obtained in excellent yields by using milder conditions, shorter reaction times, and lower catalyst loadings than those required for a heterogeneous Au nanopore catalyst. The catalytic system could be recovered and reused for five consecutive runs without any loss of activity. The combination of bis(pinacolato)- diboron with the 1,2-disilane in the presence of Au/TiO2 allowed for the σ-bond metathesis to take place and the in situ formation of the Au nanoparticle-tethered silylborane. Given that the Au-catalyzed silaboration of alkynes is faster than the rates of the corresponding disilylation and diboration pathways, we were able to achieve the indirect silaboration of alkynes with good chemoselectivities (65–85 %) without the direct use of silylboranes, which are expensive and difficult to synthesize.
- Kidonakis, Marios,Stratakis, Manolis
-
p. 4265 - 4271
(2017/11/09)
-
- An experimental and theoretical study into the facile, homogenous (N-heterocyclic carbene)2-Pd(0) catalyzed diboration of internal and terminal alkynes
-
Pd(ITMe)2(PhCCPh) acts as a highly reactive pre-catalyst in the unprecedented homogenous catalyzed diboration of terminal and internal alkynes, yielding a number of novel and known syn-1,2-diborylalkenes in a 100% stereoselective manner. DFT calculations suggest that a similar reaction pathway to that proposed for platinum phosphine analogues is followed, and that destabilization of key intermediates by the NHCs is vital to the overall success for the palladium-catalyzed B-B addition to alkynes.
- Ansell, Melvyn B.,Menezes Da Silva, Vitor H.,Heerdt, Gabriel,Braga, Ataualpa A. C.,Spencer, John,Navarro, Oscar
-
p. 7461 - 7467
(2016/10/21)
-
- Solvent-and ligand-free diboration of alkynes and alkenes catalyzed by platinum nanoparticles on titania
-
Platinum nanoparticles supported on titania efficiently catalyzed the diboration of alkynes and alkenes under solvent-and ligand-free conditions in air. The cis-1,2-diborylalkenes and 1,2-diborylalkanes were obtained in moderate to excellent yields following, in most cases, a simple filtration workup protocol. The versatility of the cis-1,2-diboronvinyl compounds was demonstrated in a series of organic transformations, including the Suzuki-Miyaura cross coupling and the boron-halogen exchange. Click diboration: The diboration of alkynes and alkenes catalyzed by platinum nanoparticles on titania is shown to take place under solvent-and ligand-free conditions in air. The 1,2-diboronvinyl compounds are obtained with exclusive cis stereochemistry and are subjected to different useful chemical transformations.
- Alonso, Francisco,Moglie, Yanina,Pastor-Perez, Laura,Sepulveda-Escribano, Antonio
-
p. 857 - 865
(2014/03/21)
-
- Remarkable catalytic property of nanoporous gold on activation of diborons for direct diboration of alkynes
-
A novel catalytic property of nanoporous gold for activation of bis(pinacolato)diboron has been reported that allows the direct diboration of alkynes to proceed sufficiently in a heterogeneous process. The experimental results revealed that the nanoporous gold catalyst is able to cleave the B-B bond of bis(pinacolato)diboron without using any additives.
- Chen, Qiang,Zhao, Jian,Ishikawa, Yoshifumi,Asao, Naoki,Yamamoto, Yoshinori,Jin, Tienan
-
supporting information
p. 5766 - 5769
(2013/12/04)
-
- Stereoselective single (copper) or double (platinum) boronation of alkynes catalyzed by magnesia-supported copper oxide or platinum nanoparticles
-
Copper(II) oxide nanoparticles supported on magnesia have been prepared from CuII supported on magnesia by hydrogen reduction at 400°C followed by storage under ambient conditions. X-ray photoelectron spectroscopy of the material clearly shows that immediately after the reduction copper(0)-metal nanoparticles are present on the magnesia support, but they undergo fast oxidation to copper oxide upon contact with the ambient for a short time. TEM images show that the catalytically active CuO/MgO material is formed of well-dispersed copper oxide nanoparticles supported on fibrous MgO. CuO/MgO exhibits a remarkable catalytic activity for the monoborylation of aromatic, aliphatic, terminal, and internal alkynes, the products being formed with high regio-(borylation at the less substituted carbon) and stereoselectivity (trans-configured). CuO/MgO exhibits complete chemoselectivity towards the monoborylation of alkynes in the presence of alkenes. Other metal nanoparticles such as gold or palladium are inactive towards borylation, but undergo undesirable oligomerization or partial hydrogenation of the Ci£C triple bond. In contrast, platinum, either supported on magnesia or on nanoparticulate ceria, efficiently promotes the stereoselective diborylation of alkynes to yield a cis-configured diboronate alkene. By using platinum as the catalyst we have developed a tandem diborylation/hydrogenation reaction that gives vic-diboronated alkanes from alkynes in one pot.
- Grirrane, Abdessamad,Corma, Avelino,Garcia, Hermenegildo
-
scheme or table
p. 2467 - 2478
(2011/04/24)
-
- One-pot synthesis of α,α-difluoroimines from alkynes through tandem catalytic diboration/fluorination/imination reaction
-
Tandem catalytic diboration/fluorination/imination of arylacetylenes leads to the formation of α,α-difluoroimines, where the adjacent C{double bond, long}N and C-F2 bonds are formed simultaneously. The convenient one-pot protocol involves a Pt(0)-catalyzed diboration of terminal or internal arylalkynes followed by electrophilic fluorination with Selectfluor in the presence of primary amines and a dehydrating agent. A plausible mechanism for the three consecutive steps (diboration/fluorination/imination) is suggested in accordance with the electronic properties of the substrates. Alkynes/catalytic diboration/alkenyl diboronate esters/Selectfluor/electrophilic fluorination/α,α-difluoroimines.
- Ramírez, Jesús,Fernández, Elena
-
p. 3841 - 3845
(2008/02/07)
-
- Catalytic diboration of unsaturated molecules with platinum(0)-NHC: Selective synthesis of 1,2-dihydroxysulfones
-
Readily available N-heterocyclic platinum complexes provide active catalytic species for 1,2-diboration and anticipate a wide range of applications in alkenes and alkynes. Unprecedented catalytic B - B addition of heteroatom-containing sub-strates provided high selectivity into organosulfur - diboronate esters. Their in situ basic oxidation afforded the desired 1,2-dihydroxysulfones in high yields.
- Lillo, Vanesa,Mata, Jose,Ramirez, Jesus,Peris, Eduardo,Fernandez, Elena
-
p. 5829 - 5831
(2008/10/09)
-
- Convenient synthesis of α,α-difluorinated carbonyl compounds from alkynes through a fluoro-deboronation process
-
Catalytic diboration of alkynes towards alkenyl diboronates provides suitable intermediates that can be converted into α-fluorinated and α,α-difluorinated carbonyl compounds via electrophilic fluorination with Selectfluor. Georg Thieme Verlag Stuttgart.
- Ramirez, Jesus,Fernandez, Elena
-
p. 1698 - 1700
(2007/10/03)
-
- CATALYZED ENANTIOSELECTIVE TRANSFORMATION OF ALKENES
-
Enantioselective catalytic reactions that operate directly on unactivated alkenes for the preparation of chiral organic building blocks and new materials. More particularly, a catalyzed enantioselective reaction that operates on an unsaturated hydrocarbon, such as an alkene, to provide an enantiomerically enriched reactive organometallic intermediate, which can be converted to a variety of multifunctional optically active reaction products.
- -
-
Page/Page column 61
(2010/02/10)
-
- Catalytic enantioselective hydrogenation of vinyl bis(boronates)
-
Catalytic enantioselective hydrogenation of prochiral vinylmetallic reagents can provide an attractive alternative to hydrometalation and bismetalation of alkenes. In this contribution, the first highly enantioselective hydrogenation of vinyl boronic esters is described. The chiral reduction products are versatile intermediates for chemical synthesis. Copyright
- Morgan, Jeremy B.,Morken, James P.
-
p. 15338 - 15339
(2007/10/03)
-
- Platinum(0)-catalyzed diboration of alkynylboronates and alkynylphosphonates with bis(pinacolato)diborane(4) (see abstract)
-
The platinum(0)-catalyzed diboration addition reaction of bis(pinacolato)diborane(4) [(Me4C2O2)BB(O2C2Me4 ), 1] with various 1-alkynylphosphonates and 1-alkynylboronates 3a-d gave the desired novel cis-1,2-diboronated vinylphosphonate and trisboronated alkene products 5a, 5b and 5c, 5d respectively, in high yields. No detectable amount of the desired trisboronated alkene products 5c and 5d were isolated when the alkynylboronate was immediately added to a toluene solution of the catalyst and bis(pinacolato)diborane(4) followed by stirring overnight at 80 °C. Under these conditions, cis-1,2-diboronated alkenes 6c and 6d were obtained in 100% conversion yields. Only after changing the reaction conditions were 5c and 5d obtained in high yields. The structure and configuration of the new compounds have been fully characterized by 1H, 13C, 31P, and 11B NMR, GCMS, elemental analysis, and single-crystal X-ray structure determination. The structure of 5d was found to be fully isomorphous to that of 5c, with the C6H5 ring located in place (and similarly disordered about the 2-fold symmetry axis) of the C4H9 residue; therefore the results of the diffraction analysis, crystal data, and details of the structure determination of 5d are not included.
- Abu Ali, Hijazi,Al Quntar, Abed El Aziz,Goldberg, Israel,Srebnik, Morris
-
p. 4533 - 4539
(2008/10/08)
-
- Highly efficient monophosphine platinum catalysts for alkyne diboration
-
Automated parallel screening using a series of in situ generated platinum(0) phosphine complexes has allowed the identification of improved catalysts for the diboration of alkynes using bis(pinacolato)diboron (B2(pin)2, pin = OCMe2CMe2O). A selection of phosphines were added to [Pt(NBE)3] (NBE = norbornene), which contains only labile mono-olefin ligands, and the activity of the resulting solutions as catalysts for the diboration of 4-CF3C6H4C≡CC6H 4CF3-4′ 1 by B2(pin)2 was investigated by in situ GC-MS and/or NMR spectroscopy. This allowed the optimum phosphine : platinum stoichiometry to be identified as 1 : 1, and the large differences in catalyst activity depending on the nature of the phosphine to be quantified. The best phosphines employed in the study, PCy3 and PPh2(o-Tol) (o-Tol = C6H4Me-o), give activities orders of magnitude greater than the worst, such as P(C6F5)3 and PBut3. The monophosphine catalysts function much more efficiently than previous catalysts for a range of alkynes allowing diborations to be performed at ambient temperatures. The diboration of strained cyclic alkenes and some vinyl- and allyl-arenes proceeded well, although the catalysts were inactive for other olefinic systems examined. As a result of these studies, the isolable and stable compound [Pt(PCy3)(η2-C2H4) 2] was identified as an excellent catalyst for alkyne diboration even at room temperature.
- Thomas,Souza,Marder
-
p. 1650 - 1656
(2007/10/03)
-