scholarly journals General and selective deoxygenation by hydrogen using a reusable earth-abundant metal catalyst

2019 ◽  
Vol 5 (11) ◽  
pp. eaav3680 ◽  
Author(s):  
T. Schwob ◽  
P. Kunnas ◽  
N. de Jonge ◽  
C. Papp ◽  
H.-P. Steinrück ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Gas ◽  
Metal Catalyst ◽  
Tertiary Alcohols ◽  
Aryl Ketones ◽  
Earth Abundant ◽  
Fuels And Chemicals ◽  
Cost Efficient ◽  
Economic Upgrading ◽  
Selective Deoxygenation

Chemoselective deoxygenation by hydrogen is particularly challenging but crucial for an efficient late-stage modification of functionality-laden fine chemicals, natural products, or pharmaceuticals and the economic upgrading of biomass-derived molecules into fuels and chemicals. We report here on a reusable earth-abundant metal catalyst that permits highly chemoselective deoxygenation using inexpensive hydrogen gas. Primary, secondary, and tertiary alcohols as well as alkyl and aryl ketones and aldehydes can be selectively deoxygenated, even when part of complex natural products, pharmaceuticals, or biomass-derived platform molecules. The catalyst tolerates many functional groups including hydrogenation-sensitive examples. It is efficient, easy to handle, and conveniently synthesized from a specific bimetallic coordination compound and commercially available charcoal. Selective, sustainable, and cost-efficient deoxygenation under industrially viable conditions seems feasible.

Direct Asymmetric α-Hydroxylation of Cyclic α-Branched Ketones through Enol Catalysis

Synlett ◽  
2018 ◽  
Vol 30 (01) ◽  
pp. 49-53 ◽  
Author(s):  
Benjamin List ◽  
Grigory Shevchenko ◽  
Gabriele Pupo
Keyword(s):  
Natural Products ◽  
Phosphoric Acid ◽  
Carbonyl Compounds ◽  
Tertiary Alcohols ◽  
Chiral Phosphoric Acid

Enantiopure α-hydroxy carbonyl compounds are common scaffolds in natural products and pharmaceuticals. Although indirect approaches towards their synthesis are known, direct asymmetric methodologies are scarce. Herein, we report the first direct asymmetric α-hydroxylation of α-branched ketones through enol catalysis, enabling a facile access to valuable α-keto tertiary alcohols. The transformation, characterized by the use of nitrosobenzene as the oxidant and a new chiral phosphoric acid as the catalyst, delivers a good scope and excellent enantioselectivities.

scholarly journals Sustainable Hydrogenation of Nitroarenes to Anilines with Highly Active In-Situ Generated Copper Nanoparticles

2020 ◽  
Author(s):  
Fatma Pelin Kinik ◽  
Tu Ngugen ◽  
Mounir Mensi ◽  
Christopher Ireland ◽  
Kyriakos Stylianou ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Hydrogenation Reaction ◽  
Hydrogen Gas ◽  
Proof Of Concept ◽  
Drug Molecules ◽  
Highly Active ◽  
The Earth ◽  
Earth Abundant ◽  
Stability Issues

<div> <div> <div> <p>Metal nanoparticles (NPs) are usually stabilized by a capping agent, a surfactant, or a support material, to maintain their integrity. However, these strategies can impact their intrinsic catalytic activity. Here, we demonstrate that the in-situ formation of copper NPs (Cu0NPs) upon the reduction of the earth-abundant Jacquesdietrichite mineral with ammonia borane (NH3BH3, AB) can provide an alternative solution for stability issues. During the formation of Cu0NPs, hydrogen gas is released from AB, and utilized for the reduction of nitroarenes to their corresponding anilines, at room temperature and under ambient pressure. After the nitroarene-to-aniline conversion is completed, regeneration of the mineral occurs upon the exposure of Cu0NPs to air. Thus, the hydrogenation reaction can be performed multiple times without the loss of the Cu0NPs’ activity. As a proof-of-concept, the hydrogenation of drug molecules “flutamide” and “nimesulide” was also performed and isolated their corresponding amino-compounds in high selectivity and yield. </p> </div> </div> </div>

scholarly journals Transesterification of (hetero)aryl esters with phenols by an Earth-abundant metal catalyst

RSC Advances ◽  
2018 ◽  
Vol 8 (44) ◽  
pp. 25168-25176 ◽  
Author(s):  
Jianxia Chen ◽  
E. Namila ◽  
Chaolumen Bai ◽  
Menghe Baiyin ◽  
Bao Agula ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Metal Species ◽  
Metal Catalyst ◽  
Earth Abundant

Readily available and inexpensive Earth-abundant alkali metal species are used as efficient catalysts for the transesterification of aryl or heteroaryl esters with phenols which is a challenging and underdeveloped transformation.

scholarly journals Pd(II)-Catalyzed C-H Acylation of (Hetero)arenes—Recent Advances

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3247 ◽  
Author(s):  
Carlos Santiago ◽  
Nuria Sotomayor ◽  
Esther Lete
Keyword(s):  
Natural Products ◽  
Toxic Metal ◽  
Complex Molecules ◽  
Metal Waste ◽  
Recent Advances ◽  
Aryl Ketones ◽  
Recent Developments ◽  
Further Development

Di(hetero)aryl ketones are important motifs present in natural products, pharmaceuticals or agrochemicals. In recent years, Pd(II)-catalyzed acylation of (hetero)arenes in the presence of an oxidant has emerged as a catalytic alternative to classical acylation methods, reducing the production of toxic metal waste. Different directing groups and acyl sources are being studied for this purpose, although further development is required to face mainly selectivity problems in order to be applied in the synthesis of more complex molecules. Selected recent developments and applications are covered in this review.

scholarly journals Homogeneous cobalt-catalyzed reductive amination for synthesis of functionalized primary amines

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Kathiravan Murugesan ◽  
Zhihong Wei ◽  
Vishwas G. Chandrashekhar ◽  
Helfried Neumann ◽  
Anke Spannenberg ◽  
...  
Keyword(s):  
Density Functional ◽  
Reductive Amination ◽  
Primary Amines ◽  
Metal Catalyst ◽  
Gaseous Ammonia ◽  
Free Energy Surface ◽  
Chemical Research ◽  
Rate Determining Step ◽  
Earth Abundant ◽  
Density Functional Theory Computation

AbstractThe development of earth abundant 3d metal-based catalysts continues to be an important goal of chemical research. In particular, the design of base metal complexes for reductive amination to produce primary amines remains as challenging. Here, we report the combination of cobalt and linear-triphos (bis(2-diphenylphosphinoethyl)phenylphosphine) as the molecularly-defined non-noble metal catalyst for the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds, gaseous ammonia and hydrogen in good to excellent yields. Noteworthy, this cobalt catalyst exhibits high selectivity and as a result the -NH2 moiety is introduced in functionalized and structurally diverse molecules. An inner-sphere mechanism on the basis of the mono-cationic [triphos-CoH]+ complex as active catalyst is proposed and supported with density functional theory computation on the doublet state potential free energy surface and H2 metathesis is found as the rate-determining step.

scholarly journals Using nature’s blueprint to expand catalysis with Earth-abundant metals

Science ◽  
2020 ◽  
Vol 369 (6505) ◽  
pp. eabc3183 ◽  
Author(s):  
R. Morris Bullock ◽  
Jingguang G. Chen ◽  
Laura Gagliardi ◽  
Paul J. Chirik ◽  
Omar K. Farha ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Physical Properties ◽  
High Activity ◽  
Precious Metals ◽  
Sustainable Production ◽  
Platinum Group Metals ◽  
Catalytic Reactions ◽  
Redox Transformations ◽  
Earth Abundant ◽  
Fuels And Chemicals

Numerous redox transformations that are essential to life are catalyzed by metalloenzymes that feature Earth-abundant metals. In contrast, platinum-group metals have been the cornerstone of many industrial catalytic reactions for decades, providing high activity, thermal stability, and tolerance to chemical poisons. We assert that nature’s blueprint provides the fundamental principles for vastly expanding the use of abundant metals in catalysis. We highlight the key physical properties of abundant metals that distinguish them from precious metals, and we look to nature to understand how the inherent attributes of abundant metals can be embraced to produce highly efficient catalysts for reactions crucial to the sustainable production and transformation of fuels and chemicals.

A Study on Spirituous Liquor Efficiency Using Direct Alcohol Fuel Cell

2015 ◽  
Vol 658 ◽  
pp. 129-132
Author(s):  
Nutthapon Wongyao ◽  
Apichai Therdthianwong ◽  
Supaporn Therdthianwong
Keyword(s):  
Fuel Cell ◽  
Electrical Power ◽  
Open Circuit ◽  
Ethanol Solution ◽  
Hydrogen Gas ◽  
Initial Time ◽  
Metal Catalyst ◽  
Pure Ethanol ◽  
Direct Alcohol Fuel Cell ◽  
Alcohol Fuel

The electro-oxidation of 40 degree of alcohol as a local-commercial of spirituous liquor in Thailand compared with pure ethanol solution on the metal catalyst of PtSn/C was carried out. With using the 5 cm2 anode electrode of PtSn/C catalyst, the direct alcohol fuel cell was employed and then fed with 1 M of spirituous liquor at flow rate of 1 ml/min under operating condition of atmospheric pressure. The results from an output electrical power of 40 degree liquor fed into direct alcohol fuel cell (celled 40DFC) indicated that, at the initial time, the spirituous liquor provided the higher power density of 6 mW/cm2 compared with ethanol solution (celled DEFC) at the same concentration. For the cell open circuit voltage (OCV) using the spirituous liquor as fuel, it was 0.63 V which slightly lower than ethanol solution one. Nevertheless, 15 minutes left after applying the liquor, the cell performance was dramatic dropped due to the poisoned species of sulfur contained in liquor. The anode catalyst performance loss was also proved by using hydrogen gas for rechecking of the permanent degradation of fuel cell caused by feeding liquor onto the PtSn catalyst surface.

scholarly journals A practical synthesis of long-chain iso-fatty acids (iso-C12–C19) and related natural products

2013 ◽  
Vol 9 ◽  
pp. 1807-1812 ◽  
Author(s):  
Mark B Richardson ◽  
Spencer J Williams
Keyword(s):  
Fatty Acids ◽  
Natural Products ◽  
Selective Reduction ◽  
Isopropyl Group ◽  
Tertiary Alcohols ◽  
Practical Synthesis ◽  
Long Chain

A gram-scale synthesis of terminally-branched iso-fatty acids (iso-C12–C19) was developed commencing with methyl undec-10-enoate (methyl undecylenate) (for iso-C12–C14) or the C15and C16lactones pentadecanolide (for iso-C15–C17) and hexadecanolide (for iso-C18–C19). Central to the approaches outlined is the two-step construction of the terminal isopropyl group through addition of methylmagnesium bromide to the ester/lactones and selective reduction of the resulting tertiary alcohols. Thus, the C12, C17and C18iso-fatty acids were obtained in three steps from commercially-available starting materials, and the remaining C13–C16and C19iso-fatty acids were prepared by homologation or recursive dehomologations of these fatty acids or through intercepting appropriate intermediates. Highlighting the synthetic potential of the iso-fatty acids and various intermediates prepared herein, we describe the synthesis of the natural products (S)-2,15-dimethylpalmitic acid, (S)-2-hydroxy-15-methylpalmitic acid, and 2-oxo-14-methylpentadecane.

scholarly journals Selective Manganese-Catalyzed Dimerization and Cross-Coupling of Terminal Alkynes

2021 ◽  
Author(s):  
Stefan Weber ◽  
Luis F. Veiros ◽  
Karl Kirchner
Keyword(s):  
Dft Calculations ◽  
Precious Metal ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
Metal Catalyst ◽  
Catalyst Loading ◽  
Terminal Alkynes ◽  
Migratory Insertion ◽  
Earth Abundant ◽  
First Time

<div>For the first time, an efficient manganese-catalyzed dimerization of terminal alkynes to afford 1,3-enynes is described. This reaction is atom economic, implementing an inexpensive, earth abundant non-precious metal catalyst. The pre-catalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid C-H bond cleavage of the alkyne forming an active Mn(I) acetylide catalyst [Mn(dippe)(CO)2(C≡CPh)(η2-HC≡CPh)] together with liberated butanal. A range of aromatic and aliphatic terminal alkynes were efficiently and selectively converted into head-to-head Z-1,3-enynes and head-to-tail gem-1,3-enynes, respectively, in good to excellent yields. Moreover, cross-coupling of aromatic and aliphatic alkynes yields selectively head-to-tail gem-1,3-enynes. In all cases, the reactions were performed at 70 °C with a catalyst loading of 1-2 mol %. A mechanism based on DFT calculations is presented.</div><div><br></div>

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