Ni-Catalyzed regio- and stereoselective addition of arylboronic acids to terminal alkynes with a directing group tether

2017 ◽  
Vol 53 (27) ◽  
pp. 3894-3897 ◽  
Author(s):  
Madala Hari Babu ◽  
Gadi Ranjith Kumar ◽  
Ruchir Kant ◽  
Maddi Sridhar Reddy
Keyword(s):  
Catalytic System ◽  
Terminal Alkynes ◽  
Arylboronic Acids ◽  
Stereoselective Addition ◽  
Directing Group ◽  
First Time ◽  
P Addition

Addition of arylboronic acids to directing group tethered acetylenes in a regio and stereoselective manner using an inexpensive catalytic system is achieved for the first time to access highly sought after allyl/homoallyl alcohol/amine units.

scholarly journals Synthesis of New Functionally Substituted 9-Azabicyclo[4.2.1]nona-2,4,7-Trienes by Cobalt(I)-Catalyzed [6π + 2π]-Cycloaddition of N-Carbocholesteroxyazepine to Alkynes

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2932
Author(s):  
Gulnara N. Kadikova ◽  
Vladimir A. D’yakonov ◽  
Usein M. Dzhemilev
Keyword(s):  
Catalytic System ◽  
Nmr Spectra ◽  
Two Dimensional ◽  
Terminal Alkynes ◽  
First Time ◽  
Natural Metabolite ◽  
Covalently Bound

Catalytic [6π + 2π]-cycloaddition of N-carbocholesteroxyazepine with functionally substituted terminal alkynes and 1,4-butynediol was performed for the first time under the action of the Co(acac)2(dppe)/Zn/ZnI2 three-component catalytic system. The reaction gave previously undescribed but promising 9-azabicyclo[4.2.1]nona-2,4,7-trienes (in 79–95% yields), covalently bound to a natural metabolite, cholesterol. The structure of the synthesized azabicycles was confirmed by analysis of one- and two-dimensional (1H, 13C, DEPT 13C, COSY, NOESY, HSQC, HMBC) NMR spectra.

scholarly journals Palladium catalyzed regioselective B–C(sp) coupling via direct cage B–H activation: synthesis of B(4)-alkynylated o-carboranes

2016 ◽  
Vol 7 (9) ◽  
pp. 5838-5845 ◽  
Author(s):  
Yangjian Quan ◽  
Cen Tang ◽  
Zuowei Xie
Keyword(s):  
Terminal Alkynes ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
First Time ◽  
Intermolecular Coupling

Palladium-catalyzed direct intermolecular coupling of o-carboranes with alkynyl bromides or terminal alkynes has been achieved, for the first time, with the help of a traceless directing group –COOH, leading to the synthesis of a series of new cage B(4)-alkynylated-o-carboranes in high yields with excellent regioselectivity.

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.

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.

scholarly journals Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Hui-Ju Chen ◽  
Chien-Cheng Chiu ◽  
Tsui Wang ◽  
Dong-Sheng Lee ◽  
Ta-Jung Lu
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
High Efficiency ◽  
Aqueous Media ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Terminal Alkynes ◽  
Wide Range ◽  
Transfer Hydrogenation Reaction

The bis-NHC–Ag/Pd(OAc)2 catalytic system (NHC = N-heterocyclic carbene), a combination of bis-NHC–Ag complex and Pd(OAc)2, was found to be a smart catalyst in the Pd-catalyzed transfer hydrogenation of various functionalized arenes and internal/terminal alkynes. The catalytic system demonstrated high efficiency for the reduction of a wide range of various functional groups such as carbonyls, alkynes, olefins, and nitro groups in good to excellent yields and high chemoselectivity for the reduction of functional groups. In addition, the protocol was successfully exploited to stereoselectivity for the transformation of alkynes to alkenes in aqueous media under air. This methodology successfully provided an alternative useful protocol for reducing various functional groups and a simple operational protocol for transfer hydrogenation.

Ni-catalyzed direct iminoalkynylation of unactivated olefins with terminal alkynes: facile access to alkyne-labelled pyrrolines

2021 ◽  
Author(s):  
Xingjie Zhang ◽  
Di Qi ◽  
Chenchen Jiao ◽  
Zhiguo Zhang ◽  
Xiaopan Liu ◽  
...  
Keyword(s):  
Radical Cyclization ◽  
Terminal Alkynes ◽  
Mild Conditions ◽  
Type Coupling ◽  
First Time

The direct iminoalkynylation of unactivated olefins with terminal alkynes is achieved for the first time by nickel-catalyzed cascade iminyl-radical cyclization/Sonogashira-type coupling of γ,δ-unsaturated oxime esters under mild conditions. This transformation...

scholarly journals C–C (alkynylation) vs C–O (ether) bond formation under Pd/C–Cu catalysis: synthesis and pharmacological evaluation of 4-alkynylthieno[2,3-d]pyrimidines

2011 ◽  
Vol 7 ◽  
pp. 338-345 ◽  
Author(s):  
Dhilli Rao Gorja ◽  
K Shiva Kumar ◽  
K Mukkanti ◽  
Manojit Pal
Keyword(s):  
Cytotoxic Activity ◽  
Catalytic System ◽  
High Selectivity ◽  
Bond Formation ◽  
Terminal Alkynes ◽  
Ether Bond ◽  
Pharmacological Evaluation

The Pd/C–CuI–PPh3 catalytic system facilitated C–C bond formation between 4-chlorothieno[2,3-d]pyrimidines and terminal alkynes in methanol with high selectivity without generating any significant side products arising from C–O bond formation between the chloro compounds and methanol. A variety of novel 4-alkynylthieno[2,3- d]pyrimidines were prepared via alkynylation of 4-chlorothieno[2,3-d]pyrimidines in good to excellent yields. Some of the compounds synthesized were tested for cytotoxic activity in vitro.

Nickel Catalyzedsyn-Selective Aryl Nickelation and Cyclization of Aldehyde/Enone-Tethered Terminal Alkynes with Arylboronic Acids

2018 ◽  
Vol 83 (24) ◽  
pp. 15361-15371 ◽  
Author(s):  
Manda Rajesh ◽  
Maneesh Kumar Reddy Singam ◽  
Surendra Puri ◽  
Sridhar Balasubramanian ◽  
Maddi Sridhar Reddy
Keyword(s):  
Terminal Alkynes ◽  
Arylboronic Acids
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