768-59-2Relevant articles and documents
Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
supporting information, p. 9029 - 9039 (2021/06/28)
Chemoselective deoxygenation of carbonyls and alcohols using hydrogen by heterogeneous base-metal catalysts is crucial for the sustainable production of fine chemicals and biofuels. We report an aluminum metal-organic framework (DUT-5) node support cobalt(II) hydride, which is a highly chemoselective and recyclable heterogeneous catalyst for deoxygenation of a range of aromatic and aliphatic ketones, aldehydes, and primary and secondary alcohols, including biomass-derived substrates under 1 bar H2. The single-site cobalt catalyst (DUT-5-CoH) was easily prepared by postsynthetic metalation of the secondary building units (SBUs) of DUT-5 with CoCl2 followed by the reaction of NaEt3BH. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of CoII and AlIII centers in DUT-5-CoH and DUT-5-Co after catalysis. The coordination environment of the cobalt center of DUT-5-Co before and after catalysis was established by extended X-ray fine structure spectroscopy (EXAFS) and density functional theory. The kinetic and computational data suggest reversible carbonyl coordination to cobalt preceding the turnover-limiting step, which involves 1,2-insertion of the coordinated carbonyl into the cobalt-hydride bond. The unique coordination environment of the cobalt ion ligated by oxo-nodes within the porous framework and the rate independency on the pressure of H2 allow the deoxygenation reactions chemoselectively under ambient hydrogen pressure.
Ruthenium-catalyzed ester reductions applied to pharmaceutical intermediates
Shaalan, Youssef,Boulton, Lee,Jamieson, Craig
supporting information, p. 2745 - 2751 (2020/11/30)
Ruthenium pincer complexes were synthesized and used for catalytic ester reductions under mild conditions (～5 bar of hydrogen). An experimental design approach was used to optimize the conditions for yield, purity, and robustness. Evidence for the catalytically active ruthenium dihydride species is presented. Observed intermediates and side products, as well as time-course data, were used to build mechanistic insight. The optimized procedure was further demonstrated through scaled-up reductions of two pharmaceutically relevant esters, both in batch and continuous flow.
Selective hydrogenation of primary amides and cyclic di-peptides under Ru-catalysis
Subaramanian, Murugan,Sivakumar, Ganesan,Babu, Jessin K.,Balaraman, Ekambaram
supporting information, p. 12411 - 12414 (2020/10/30)
A ruthenium(II)-catalyzed selective hydrogenation of challenging primary amides and cyclic di-peptides to their corresponding primary alcohols and amino alcohols, respectively, is reported. The hydrogenation reaction operates under mild and eco-benign conditions and can be scaled-up.
Polymer-Anchored Bifunctional Pincer Catalysts for Chemoselective Transfer Hydrogenation and Related Reactions
Mujahed, Shrouq,Valentini, Federica,Cohen, Shirel,Vaccaro, Luigi,Gelman, Dmitri
, p. 4693 - 4699 (2019/10/28)
A series of polymer-supported cooperative PC(sp3)P pincer catalysts was synthesized and characterized. Their catalytic activity in the acceptorless dehydrogenative coupling of alcohols and the transfer hydrogenation of aldehydes with formic acid as a hydrogen source was investigated. This comparative study, examining homogeneous and polymer-tethered species, proved that carefully designing a link between the support and the catalytic moiety, which takes into consideration the mechanism underlying the target transformation, might lead to superior heterogeneous catalysis.
Hydrosilylation of carbonyl and carboxyl groups catalysed by Mn(i) complexes bearing triazole ligands
Martínez-Ferraté, Oriol,Chatterjee, Basujit,Werlé, Christophe,Leitner, Walter
, p. 6370 - 6378 (2019/11/20)
Manganese(i) complexes bearing triazole ligands are reported as catalysts for the hydrosilylation of carbonyl and carboxyl compounds. The desired reaction proceeds readily at 80 °C within 3 hours at catalyst loadings as low as 0.25 to 1 mol%. Hence, good to excellent yields of alcohols could be obtained for a wide range of substrates including ketones, esters, and carboxylic acids illustrating the versatility of the metal/ligand combination.
Nickel-Catalyzed Stereodivergent Synthesis of E- and Z-Alkenes by Hydrogenation of Alkynes
Murugesan, Kathiravan,Bheeter, Charles Beromeo,Linnebank, Pim R.,Spannenberg, Anke,Reek, Joost N. H.,Jagadeesh, Rajenahally V.,Beller, Matthias
, p. 3363 - 3369 (2019/06/28)
A convenient protocol for stereodivergent hydrogenation of alkynes to E- and Z-alkenes by using nickel catalysts was developed. Simple Ni(NO3)2?6 H2O as a catalyst precursor formed active nanoparticles, which were effective for the semihydrogenation of several alkynes with high selectivity for the Z-alkene (Z/E>99:1). Upon addition of specific multidentate ligands (triphos, tetraphos), the resulting molecular catalysts were highly selective for the E-alkene products (E/Z>99:1). Mechanistic studies revealed that the Z-alkene-selective catalyst was heterogeneous whereas the E-alkene-selective catalyst was homogeneous. In the latter case, the alkyne was first hydrogenated to a Z-alkene, which was subsequently isomerized to the E-alkene. This proposal was supported by density functional theory calculations. This synthetic methodology was shown to be generally applicable in >40 examples and scalable to multigram-scale experiments.
Mechanistic Study of Palladium-Catalyzed Hydroesterificative Copolymerization of Vinyl Benzyl Alcohol and CO
Yee, Gereon M.,Wang, Tong,Hillmyer, Marc A.,Tonks, Ian A.
, p. 1778 - 1786 (2019/04/30)
The copolymerization of vinyl benzyl alcohol (VBA) and carbon monoxide (CO) to give a new polyester poly(VBA-CO) has been achieved via palladium-catalyzed hydroesterification. Reaction conditions involve moderate temperatures, moderate to low CO pressures, and low catalyst loadings to give a low molar mass (Mn 3-4 kg/mol) polymer as a 2:1 mixture of linear to branched repeat units. The polymer molar mass increase is consistent with a step-growth polymerization mechanism, and ester yields of >97% are achieved within 24 h. However, increases in Mn cease beyond 16 h. Control experiments indicate that the degree of polymerization is limited due to a combination of side reactions such as alcoholic end-group oxidation, hydroxycarbonylation, and alcohol acetylation, which lead to the degradation of monomeric and polymeric end groups. When a less promiscuous substrate is used such as 10-undecenol, higher molar masses (Mn 16 kg/mol) are achieved. This method has the potential to be a mild route to new polyester architectures with appropriate mitigation of side reactions.
Nickel boride mediated chemoselective deprotection of 1,1-diacetates to aldehydes and deprotection with concomitant reduction to alcohols at ambient temperature
Bartwal, Gaurav,Saroha, Mohit,Khurana, Jitender.M.
, p. 97 - 103 (2017/12/28)
A variety of 1,1-diacetates have been chemoselectively and efficiently deprotected to the corresponding aldehydes as well as deprotected and concomitantly reduced to the corresponding alcohols in high yields at ambient temperature with nickel boride generated in situ using different molar ratios of sodium borohydride and nickel (II) chloride in methanol at room temperature. Deprotection and reduction of a variety of aromatic, aliphatic and heterocyclic acylals have been achieved efficiently. Mild reaction conditions, easy work-up, high yields and chemoselectivity demonstrate the efficiency of this new method.
Palladium Nanoparticle Loaded Bifunctional Silica Hybrid Material: Preparation and Applications as Catalyst in Hydrogenation Reactions
Surmiak, Sabrina K.,Doerenkamp, Carsten,Selter, Philipp,Peterlechner, Martin,Sch?fer, Andreas H.,Eckert, Hellmut,Studer, Armido
, p. 6019 - 6028 (2017/05/05)
Bifunctional mesoporous silica was prepared by co-condensation of tetraethyl orthosilicate (TEOS) with functionalized organosilanes containing azides or alkoxyamines. Orthogonal functional groups at the particles were selectively addressed in subsequent chemical modifications through “click”-chemistry (“click to ligand” strategy) and radical nitroxide exchange. Palladation with PdCl2 delivered Pd nanoparticle-loaded silica material bearing sulfoxides and additional aminoamides as stabilizing ligands by means of in situ reduction of the PdII-salt. These functional particles were successfully applied to the hydrogenation of alkynes and alkenes. Aldehyde hydrodeoxygenation and benzyl ether cleavage were achieved with these hybrid catalysts under mild conditions. Particles were analyzed by IR, TEM/STEM, EDX, and solid-state NMR spectroscopy.
An Efficient, Stable and Reusable Palladium Nanocatalyst: Chemoselective Reduction of Aldehydes with Molecular Hydrogen in Water
Kotha, Surya Srinivas,Sharma, Nidhi,Sekar, Govindasamy
supporting information, p. 1694 - 1698 (2016/10/13)
Palladium nanoparticles (Pd-BNP) stabilized by a binaphthyl-backbone can be efficiently used for the chemoselective reduction of aldehydes in the presence of hydrogen at room temperature in water. The Pd-BNP catalyst is easily recovered and reused for five catalytic cycles. (Figure presented.).
