A Pd-Catalyzed in situ domino process for mild and quantitative production of 2,5-dimethylfuran directly from carbohydrates

2017 ◽  
Vol 19 (9) ◽  
pp. 2101-2106 ◽  
Author(s):  
Hu Li ◽  
Wenfeng Zhao ◽  
Anders Riisager ◽  
Shunmugavel Saravanamurugan ◽  
Zhongwei Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Mild Conditions

A sustainable catalytic system is developed to be efficient for producing the biofuel 2,5-dimethylfuran directly from carbohydrate biomass via an in situ domino process under mild conditions.

[bmim]PF6/KOH: A Recyclable Catalytic System for an Azide–Arylacetaldehyde [3 + 2] Cycloaddition

2017 ◽  
Vol 41 (11) ◽  
pp. 631-635
Author(s):  
Yuqin Jiang ◽  
Kai Wu ◽  
Xuxia Tan ◽  
Dandan Zhang ◽  
Wenpei Dong ◽  
...  
Keyword(s):  
Transition Metal ◽  
Organic Solvent ◽  
Catalytic System ◽  
Room Temperature ◽  
Reaction Medium ◽  
Metal Catalyst ◽  
Transition Metal Catalyst ◽  
Green Protocol ◽  
Mild Conditions

A fast and green protocol for the synthesis of 1,4-disubstituted 1,2,3-triazoles from azides and arylacetaldehydes at room temperature was developed using [bmim]PF6/KOH as the reaction medium. It was found that the in situ-generated carbene from [bmim]PF6/KOH acted as the catalyst. In the absence of a transition-metal catalyst and organic solvent, this azide–arylacetaldehyde [3 + 2] cycloaddition proceeds efficiently, with high levels of regioselectivity, broad range of substrates, excellent yields and simple operation under mild conditions.

scholarly journals Copper–phenanthroline catalysts for regioselective synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and of pyrrolo[1,2-a]phenanthrolines under mild conditions

2014 ◽  
Vol 10 ◽  
pp. 692-700 ◽  
Author(s):  
Rupankar Paira ◽  
Tarique Anwar ◽  
Maitreyee Banerjee ◽  
Yogesh P Bharitkar ◽  
Shyamal Mondal ◽  
...  
Keyword(s):  
Catalytic System ◽  
Cycloaddition Reaction ◽  
Regioselective Synthesis ◽  
Azomethine Ylides ◽  
Dipolar Cycloaddition ◽  
General Applicability ◽  
Mild Conditions ◽  
Stabilized Azomethine Ylides ◽  
High Yields

A new series of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and pyrrolo[1,2-a]phenanthrolines were efficiently built up from an 8-hydroxyquinoline derivative or phenanthroline via 1,3-dipolar cycloaddition reaction involving non-stabilized azomethine ylides, generated in situ from the parent furo[3,2-h]quinoliniums/phenanthroliums, in presence of a copper(II) chloride–phenanthroline catalytic system. The methodology combines general applicability with high yields.

One-Pot Synthesis of Polysubstituted Imidazoles Based on Pd(OAc)2/Ce(SO4)2/Bi(NO3)3 Trimetallic Cascade of Decarboxylation/Wacker-Type Oxidation/Debus–Radziszewski Reaction

Synthesis ◽  
2019 ◽  
Vol 51 (17) ◽  
pp. 3221-3230 ◽  
Author(s):  
Wei Sun ◽  
Mingjuan Zhang ◽  
Peilang Li ◽  
Yiqun Li
Keyword(s):  
Catalytic System ◽  
Multicomponent Reaction ◽  
Functional Group ◽  
Cascade Process ◽  
One Pot ◽  
Aryl Aldehydes ◽  
Mild Conditions ◽  
One Pot Synthesis ◽  
System A

A novel and highly efficient one-pot synthesis of polysubstituted imidazoles from α-hydroxyphenylacetic acids, diphenylacetylene, and amines has been achieved by Pd(OAc)2/Ce(SO4)2/Bi(NO3)3 trimetallic catalytic system. A series of control experiments showed that this overall reaction occurs through a one-pot cascade process combining the steps of decarboxylation of α-hydroxyphenylacetic acids, Wacker-type oxidation of diphenylacetylene, and Debus–Radziszewski annulation of aryl aldehydes and benzil generated in situ, as well as amines. This reaction represents a novel multicomponent reaction using α-hydroxyphenylacetic acids and diphenylacetylene as sources of aryl aldehydes and a β-diketone. This process exhibits a broad substrate scope and a good functional group tolerance to assemble the corresponding polysubstituted imidazoles in excellent yields (72–88%) under mild conditions.

Bioinspired Catalysis: Self-Assembly of a Protein and DNA as a Catalyst for the Aldol Reaction in Aqueous Media

Synlett ◽  
2017 ◽  
Vol 29 (05) ◽  
pp. 560-565 ◽  
Author(s):  
Guangxun Li ◽  
Zhuo Tang ◽  
Hongxin Liu ◽  
Ying-wei Wang ◽  
Shiqi Zhang
Keyword(s):  
Catalytic System ◽  
Electrostatic Interaction ◽  
Self Assembly ◽  
Aldol Reaction ◽  
Aqueous Media ◽  
Aldol Reactions ◽  
Mild Conditions ◽  
Self Assembling ◽  
High Yields

An interesting bioinspired catalyst formed from readily available DNA and a protein through electrostatic interaction in situ proved to be efficient in catalyzing aldol reactions under mild conditions in water. By using a self-assembling catalytic system formed from protamine and DNA, aldol adducts were obtained with high yields and moderate enantioselectivities. Preliminary experiments demonstrated that the chirality of the DNA could be effectively transferred to the reaction product through the bound molecules or proteins.

Practical allylation with unactivated allylic alcohols under mild conditions

2021 ◽  
Author(s):  
Shuangshuang Li ◽  
Ju Qiu ◽  
Bowen Li ◽  
Zuolian Sun ◽  
Peizhong Xie ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Catalytic System ◽  
Allylic Alcohols ◽  
Mild Conditions ◽  
Accelerate Proton

A practical palladium/calcium catalytic system was developed for dehydrative allylation concerning unactivated allylic alcohols. EtOH solvent with H2O additive was identified as powerful media to accelerate proton transfer. That catalytic...

scholarly journals The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 822
Author(s):  
Grzegorz Mlostoń ◽  
Jakub Wręczycki ◽  
Katarzyna Urbaniak ◽  
Dariusz M. Bieliński ◽  
Heinz Heimgartner
Keyword(s):  
Elemental Sulfur ◽  
Fluoride Anion ◽  
Ring Size ◽  
Mild Conditions ◽  
Tetrabutylammonium Fluoride ◽  
Cesium Fluoride ◽  
Secondary Reactions ◽  
Derivatives Of

Fluoride anion was demonstrated as a superior activator of elemental sulfur (S8) to perform sulfurization of thioketones leading to diverse sulfur-rich heterocycles. Due to solubility problems, reactions must be carried out either in THF using tetrabutylammonium fluoride (TBAF) or in DMF using cesium fluoride (CsF), respectively. The reactive sulfurizing reagents are in situ generated, nucleophilic fluoropolysulfide anions FS(8−x)−, which react with the C=S bond according to the carbophilic addition mode. Dithiiranes formed thereby, existing in an equilibrium with the ring-opened form (diradicals/zwitterions) are key-intermediates, which undergo either a step-wise dimerization to afford 1,2,4,5-tetrathianes or an intramolecular insertion, leading in the case of thioxo derivatives of 2,2,4,4-tetramethylcyclobutane-1,3-dione to ring enlarged products. In reactions catalyzed by TBAF, water bounded to fluoride anion via H-bridges and forming thereby its stable hydrates is involved in secondary reactions leading, e.g., in the case of 2,2,4,4-tetramethyl-3-thioxocyclobutanone to the formation of some unexpected products such as the ring enlarged dithiolactone and ring-opened dithiocarboxylate. In contrast to thioketones, the fluoride anion catalyzed sulfurization of their α,β-unsaturated analogues, i.e., thiochalcones is slow and inefficient. However, an alternative protocol with triphenylphosphine (PPh3) applied as a catalyst, offers an attractive approach to the synthesis of 3H-1,2-dithioles via 1,5-dipolar electrocyclization of the in situ-generated α,β-unsaturated thiocabonyl S-sulfides. All reactions occur under mild conditions and can be considered as attractive methods for the preparation of sulfur rich heterocycles with diverse ring-size.

A new approach to arylhydrazides via the reaction of the Mitsunobu reagent with arynes: further application to access diverse nitrogen-containing heterocycles in one pot

2017 ◽  
Vol 4 (8) ◽  
pp. 1636-1639 ◽  
Author(s):  
Bin Cheng ◽  
Bian Bao ◽  
Yanhe Chen ◽  
Ning Wang ◽  
Yun Li ◽  
...  
Keyword(s):  
One Pot ◽  
New Approach ◽  
Mild Conditions ◽  
Highly Active ◽  
Active Intermediates

A new route to arylhydrazides involving the reaction of two highly active intermediates, the 1,3-zwitterion generated in situ from the Mitsunobu reagent and arynes, under mild conditions has been developed.

scholarly journals Ultra-Small Pd(0) Nanoparticles into a Designed Semisynthetic Lipase: An Efficient and Recyclable Heterogeneous Biohybrid Catalyst for the Heck Reaction under Mild Conditions

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2358 ◽  
Author(s):  
David Lopez-Tejedor ◽  
Blanca de las Rivas ◽  
Jose M. Palomo
Keyword(s):  
Catalytic Activity ◽  
Protein Structure ◽  
Heck Reaction ◽  
Catalytic Performance ◽  
Reducing Agent ◽  
Chemically Modified ◽  
Mild Conditions ◽  
In Situ Formation ◽  
Geobacillus Thermocatenulatus

A novel heterogeneous enzyme-palladium (Pd) (0) nanoparticles (PdNPs) bionanohybrid has been synthesized by an efficient, green, and straightforward methodology. A designed Geobacillus thermocatenulatus lipase (GTL) variant genetically and then chemically modified by the introduction of a tailor-made cysteine-containing complementary peptide- was used as the stabilizing and reducing agent for the in situ formation of ultra-small PdNPs nanoparticles embedded on the protein structure. This bionanohybrid was an excellent catalyst in the synthesis of trans-ethyl cinnamate by Heck reaction at 65 °C. It showed the best catalytic performance in dimethylformamide (DMF) containing 10–25% of water as a solvent but was also able to catalyze the reaction in pure DMF or with a higher amount of water as co-solvent. The recyclability and stability were excellent, maintaining more than 90% of catalytic activity after five cycles of use.

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