Catalytic One-pot Reactions Research Articles

One Pot Enzyme-Catalyzed Cascade Benefit Systems

Enzyme-catalyzed cascade reactions have attracted an increasing attention with many advantages, such as environmental protection, high efficiency and no need for intermediate purification. The present overview has summarized enzymatic cascade benefit systems, including double-enzyme, multi-enzyme, and chemical-enzyme catalytic one-pot reactions. With the continuous developments in protein engineering, metabolic engineering, synthetic biology and systems biocatalysis, multi-step biotransformations will expand the scope of application, as well as enhance the biocatalytic efficiency.

A comprehensive experimental study on the production of key platform chemicals from raw biomass

In recent years, the utilization of biomass resources in the production of industrial chemicals and fuels become more preferable when considering low cost, renewability and environmental concerns. In this study, 5-hydroxymethylfurfural and levulinic acid obtained from catalytic one-pot reaction of different feedstocks (microcrystalline cellulose, corn straw, sorghum and waste fluff) under the specified conditions (temperature, time, solvent ratio, catalyst loading) using different cosolvents (methanol, hexane, tetrahydrofuran (THF), acetone) in reaction medium. Over the Amberlyst-15 catalyst, significant increase in levulinic acid concentration was achieved using acetone as cosolvent thus 94.34 ± 5.25 mg levulinic acid was obtained from 1 g sorghum at 180 °C for 30 min. The use of polar aprotic solvents such as THF and acetone promoted further hydrolysis of raw biomass materials in reaction medium.

Reduced graphene oxide enhanced emulsification for one-pot synthesis of high-density jet fuel

Synthesis of jet fuel with high density, good low-temperature property and high thermal stability is significant to aerospace industry. Here, a great-performance jet fuel blending including bi- and tri-cyclic hydrocarbons (C10 ~ C16) is synthesized with high yield through reduced graphene oxide (rGO) assisted H2SO4 catalytic one-pot reaction of cyclopentanol and methylcyclopentane. The reaction occurs through a consecutive way of dehydration, alkylation, rearrangement and hydrogen transfer. Carbon-based materials especially rGO are used as additive to increase the carbon yield by promoting the emulsification of reactants in sulfuric acid. Promoted emulsification improves the alkylation of cyclopentanol with methylcyclopentane and makes the hydrogen transfer easier, which highly increases the conversion of methylcyclopentane (54.9%), the carbon yield (83.2%) and the selectivity (97.3%) of products. Finally, a jet-fuel-ranged blending with overall yield of 71.8% is obtained by distillation, which shows high density of 0.90 g/mL, low freezing point of ＜-72 °C and a high oxidation onset temperature of 195.0 °C. This work provides a simple, efficient and low-cost way to synthesize high performance jet fuel from biomass.

The Multiple Facets of Iodine(III) Compounds in an Unprecedented Catalytic Auto-amination for Chiral Amine Synthesis.

Iodine(III) reagents are used in catalytic one-pot reactions, first as both oxidants and substrates, then as cross-coupling partners, to afford chiral polyfunctionalized amines. The strategy relies on an initial catalytic auto C(sp(3) )-H amination of the iodine(III) oxidant, which delivers an amine-derived iodine(I) product that is subsequently used in palladium-catalyzed cross-couplings to afford a variety of useful building blocks with high yields and excellent stereoselectivities. This study demonstrates the concept of self-amination of the hypervalent iodine reagents, which increases the value of the aryl moiety.

A Low-Valent Iron Imido Heterocubane Cluster: Reversible Electron Transfer and Catalysis of Selective C-C Couplings

Enzymes and cofactors with iron–sulfur heterocubane core structures, [Fe4S4], are often found in nature as electron transfer reagents in fundamental catalytic transformations. An artificial heterocubane with a [Fe4N4] core is reported that can reversibly store up to four electrons at very negative potentials. The neutral [Fe4N4] and the singly reduced low-valent [Fe4N4]− heterocubanes were isolated and fully characterized. The low-valent species bears one unpaired electron, which is localized predominantly at one iron center in the electronic ground state but fluctuates with increasing temperatures. The electrons stored or released by the [Fe4N4]/[Fe4N4]− redox couple can be used in reductive or oxidative CC couplings and even allow catalytic one-pot reactions, which show a remarkably enhanced selectivity in the presence of the [Fe4N4] heterocubanes.

A Low-Valent Iron Imido Heterocubane Cluster: Reversible Electron Transfer and Catalysis of Selective C-C Couplings.

Enzymes and cofactors with iron-sulfur heterocubane core structures, [Fe4 S4 ], are often found in nature as electron transfer reagents in fundamental catalytic transformations. An artificial heterocubane with a [Fe4 N4 ] core is reported that can reversibly store up to four electrons at very negative potentials. The neutral [Fe4 N4 ] and the singly reduced low-valent [Fe4 N4 ](-) heterocubanes were isolated and fully characterized. The low-valent species bears one unpaired electron, which is localized predominantly at one iron center in the electronic ground state but fluctuates with increasing temperatures. The electrons stored or released by the [Fe4 N4 ]/[Fe4 N4 ](-) redox couple can be used in reductive or oxidative CC couplings and even allow catalytic one-pot reactions, which show a remarkably enhanced selectivity in the presence of the [Fe4 N4 ] heterocubanes.

Copper-Catalyzed One-Pot Oxidation–Aldol/Henry Reaction of Benzylic ­Amines to α,β-Unsaturated Methyl Ketone/Nitro Compounds

A novel one-pot synthesis of α,β-unsaturated methyl ketone/nitro compounds from benzylic amines through an oxidation–aldol/Henry reaction is reported. The reaction proceeded well by using MCPBA as oxidant and CuCl₂·2H₂O as catalyst. A variety of functionalized α,β-unsaturated methyl ketone/nitro compounds were assembled in moderate yields by application of this catalytic one-pot reaction.

Layered Materials with Coexisting Acidic and Basic Sites for Catalytic One-Pot Reaction Sequences

Acidic montmorillonite-immobilized primary amines (H-mont-NH(2)) were found to be excellent acid-base bifunctional catalysts for one-pot reaction sequences, which are the first materials with coexisting acid and base sites active for acid-base tamdem reactions. For example, tandem deacetalization-Knoevenagel condensation proceeded successfully with the H-mont-NH(2), affording the corresponding condensation product in a quantitative yield. The acidity of the H-mont-NH(2) was strongly influenced by the preparation solvent, and the base-catalyzed reactions were enhanced by interlayer acid sites.

Palladium catalyzed multicomponent reactions in ordered sequence: new syntheses of o, o′-dialkylsubstituted diarylacetylenes and diarylalkylidenehexahydromethanofluorenes

Catalytic one-pot reactions of aromatic iodides with alkyl halides, phenylacetylene or diphenylacetylene, potassium acetate or carbonate, norbornene and palladium acetate in DMF or DMA are reported. A high selectivity towards dialkylsubstituted diarylacetylenes and diarylalkylidenehexahydromethanofluorenes, respectively, has been reached.

Internal olefins to linear amines.

The selective synthesis of linear amines from internal olefins or olefin mixtures was achieved through a catalytic one-pot reaction consisting of an initial olefin isomerization followed by hydroformylation and reductive amination. Key to the success is the use of specially designed phosphine ligands in the presence of rhodium catalysts. This reaction constitutes an economically attractive and environmentally favorable synthesis of linear aliphatic amines.