A novel enantioselective synthesis of 6H-dibenzopyran derivatives by combined palladium/norbornene and cinchona alkaloid catalysis

2015 ◽  
Vol 13 (8) ◽  
pp. 2260-2263 ◽  
Author(s):  
Di Xu ◽  
Li Dai ◽  
Marta Catellani ◽  
Elena Motti ◽  
Nicola Della Ca’ ◽  
...  
Keyword(s):  
Catalytic System ◽  
Enantioselective Synthesis ◽  
Cinchona Alkaloid ◽  
System P ◽  
First Time

Chiral dibenzopyran derivatives were obtained by cinchona alkaloid, as organocatalyst, in combination, for the first time, with palladium/norbornene catalytic system.

Enantioselective synthesis of 8-azabicyclo[3.2.1]octanes via asymmetric 1,3-dipolar cycloadditions of cyclic azomethine ylides using a dual catalytic system

2019 ◽  
Vol 55 (11) ◽  
pp. 1552-1555 ◽  
Author(s):  
Hiroyuki Suga ◽  
Masahiro Yoshiwara ◽  
Takaaki Yamaguchi ◽  
Takashi Bando ◽  
Mizuki Taguchi ◽  
...  
Keyword(s):  
Catalytic System ◽  
Enantioselective Synthesis ◽  
Azomethine Ylides ◽  
Dipolar Cycloaddition ◽  
Dipolar Cycloadditions ◽  
System P

The asymmetric 1,3-dipolar cycloaddition between diazo imine-derived cyclic azomethine ylides and acryloylpyrazolidinone using a dual catalytic system is reported.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Assembly of Fluorinated Chromanones via Enantioselective Tandem Reaction

2021 ◽  
Author(s):  
Mengxue Lu ◽  
Zongli Xiong ◽  
Yuqiao Zhou ◽  
Xin Wang ◽  
Xiaoyi Li ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
Tandem Reaction ◽  
Unsaturated Aldehydes ◽  
Stereogenic Centers ◽  
First Time

The enantioselective synthesis of fluorinated tricyclic chromanones with multiple vicinal stereogenic centers has been realized for the first time, through the tandem reaction between 2-fluorinated 1-(2-hydroxyaryl)-1,3-diketones and α,β-unsaturated aldehydes. In...

Atom-transfer radical addition of fluoroalkyl bromides to alkenes via a photoredox/copper catalytic system

2021 ◽  
Author(s):  
Vladislav S. Kostromitin ◽  
Artem A. Zemtsov ◽  
Vladimir A. Kokorekin ◽  
Vitalij V. Levin ◽  
Alexander D. Dilman
Keyword(s):  
Catalytic System ◽  
Radical Addition ◽  
Atom Transfer ◽  
Alkyl Bromides ◽  
System P ◽  
Atom Transfer Radical Addition

A method for the addition of fluorinated alkyl bromides to alkenes is described.

Synthesis of 2-aminothiazoles from methylcarbonyl compounds using a Fe3O4 nanoparticle-N-halo reagent catalytic system

RSC Advances ◽  
2016 ◽  
Vol 6 (69) ◽  
pp. 64749-64755 ◽  
Author(s):  
Masoud Sadeghi ◽  
Javad Safari ◽  
Zohre Zarnegar
Keyword(s):  
Catalytic System ◽  
Fe3o4 Nanoparticle ◽  
Catalytic Systems ◽  
System P

An efficient protocol is developed for the synthesis of 2-aminothiazoles from unfunctionalized methylcarbonyl compounds using Fe3O4 nanoparticle-N-halo reagent catalytic systems.

Cobalt(ii)-catalyzed chelation-assisted C–H iodination of aromatic amides with I2

2018 ◽  
Vol 54 (11) ◽  
pp. 1359-1362 ◽  
Author(s):  
Yadagiri Kommagalla ◽  
Ken Yamazaki ◽  
Takuma Yamaguchi ◽  
Naoto Chatani
Keyword(s):  
Catalytic System ◽  
Cobalt Metal ◽  
System P

An air stable and inexpensive cobalt-metal, mild and efficient catalytic system.

Photoinduced controlled radical polymerization of methacrylates with benzaldehyde derivatives as organic catalysts

2017 ◽  
Vol 8 (23) ◽  
pp. 3574-3585 ◽  
Author(s):  
Wenchao Ma ◽  
Xianhong Zhang ◽  
Yuhong Ma ◽  
Dong Chen ◽  
Li Wang ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Radical Polymerization ◽  
Catalytic System ◽  
Controlled Radical Polymerization ◽  
System P ◽  
Benzaldehyde Derivatives ◽  
Organic Catalysts

Under 23 W CFL irradiation, block copolymers are obtained starting from a Pn-I macroinitiator in the presence of a benzaldehydic molecule-based catalytic system.

Synthesis of polyamides using palladium-on-carbon (Pd/C) as a heterogeneous, reusable and ligand-free catalytic system

RSC Advances ◽  
2015 ◽  
Vol 5 (114) ◽  
pp. 93773-93778 ◽  
Author(s):  
Anilkumar Satapathy ◽  
Sandip T. Gadge ◽  
Takehiko Sasaki ◽  
Bhalchandra M. Bhanage
Keyword(s):  
Catalytic System ◽  
Basic Problem ◽  
Catalyst Recovery ◽  
Excellent Yield ◽  
System P ◽  
Ligand Free ◽  
Palladium On Carbon

Polyamide has been synthesized by using Pd/C as a heterogeneous, phosphine-free and reusable catalytic system. The catalyst solves the basic problem of catalyst recovery and furnishes good to excellent yield of polyamides.

Systems theory

2017 ◽  
Author(s):  
Anastasia Marinopoulou
Keyword(s):  
Systems Theory ◽  
Multiple Realities ◽  
Traditional Epistemology ◽  
System P ◽  
History Of ◽  
Scientific Truth ◽  
Scientific System ◽  
First Time ◽  
Methodology Of Science ◽  
Scientific Purpose

In his systems’ theory, Luhmann attempts to redefine communication, and associates it with information. For Luhmann, communication is distinct from action (Handeln), and the rationality of the scientific system resides in the notion of Zweck, or in the ends of the sciences towards action. For the first time in the epistemological history of modernity, rationality is understood as a certain scientific purpose of action and not as the critique of scientific truth and validity of reason. The schism that Luhmann brought about between ‘traditional’ epistemology (reconsidered now as novel) and the ‘critical’ theory of science (seen by Luhmann as ‘traditional’) was irredeemable. In the following pages, I maintain that all evidence to the contrary such a divergence was inherent to modernity.Drawing on the Schützean model of multiple realities, Luhmann manages to blur the distinction between instrumentality and rationality by relativizing both within systemic complexity. According to Luhmann, complexity characterizes a multifaceted social system, such as science itself. However, I argue that where complexity, in Luhmann, interprets the systemic, it also employs presentism and partial situationalism to explain the essence and methodology of science as a system.

Sign in / Sign up

Export Citation Format

Share Document