C 1-Symmetric diphosphorus ligands in metal-catalyzed asymmetric hydrogenation to prepare chiral compounds

2021 ◽  
Author(s):  
Anirban Sen ◽  
Samir H. Chikkali
Keyword(s):  
Asymmetric Hydrogenation ◽  
Bioactive Molecules ◽  
Chiral Compounds ◽  
Drug Molecules ◽  
Metal Catalyzed

This review examines the potential of C1-symmetric diphosphorus ligands in metal-catalyzed asymmetric hydrogenation of alkenes to produce pharmaceutical intermediates, bioactive molecules, drug molecules, agrochemicals, and fragrances.

scholarly journals Organophotocatalytic selective deuterodehalogenation of aryl or alkyl chlorides

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanjun Li ◽  
Ziqi Ye ◽  
Yu-Mei Lin ◽  
Yan Liu ◽  
Yumeng Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Sodium Formate ◽  
Bioactive Molecules ◽  
Co Catalyst ◽  
Aryl Chlorides ◽  
Aryl Amine ◽  
Drug Molecules ◽  
Photocatalytic System ◽  
Site Selective ◽  
Environmentally Friendly Method

AbstractDevelopment of practical deuteration reactions is highly valuable for organic synthesis, analytic chemistry and pharmaceutic chemistry. Deuterodehalogenation of organic chlorides tends to be an attractive strategy but remains a challenging task. We here develop a photocatalytic system consisting of an aryl-amine photocatalyst and a disulfide co-catalyst in the presence of sodium formate as an electron and hydrogen donor. Accordingly, many aryl chlorides, alkyl chlorides, and other halides are converted to deuterated products at room temperature in air (>90 examples, up to 99% D-incorporation). The mechanistic studies reveal that the aryl amine serves as reducing photoredox catalyst to initiate cleavage of the C-Cl bond, at the same time as energy transfer catalyst to induce homolysis of the disulfide for consequent deuterium transfer process. This economic and environmentally-friendly method can be used for site-selective D-labeling of a number of bioactive molecules and direct H/D exchange of some drug molecules.

scholarly journals Expanding Roles for Organoboron Compounds – Versatile and Valuable Molecules for Synthetic, Biological and Medicinal Chemistry

2007 ◽  
Vol 60 (11) ◽  
pp. 795 ◽  
Author(s):  
Nicos A. Petasis
Keyword(s):  
Medicinal Chemistry ◽  
Structural Characteristics ◽  
Boronic Acids ◽  
Bioactive Molecules ◽  
Organoboron Compounds ◽  
Physiological Conditions ◽  
Present Essay ◽  
Electrophilic Reactivity ◽  
Metal Catalyzed ◽  
New Applications

The present essay offers an overview of the latest developments in the chemistry of organoboron compounds. The unique structural characteristics and the versatile reactivity profile of organoboron compounds continue to expand their roles in several areas of chemistry. A growing number of boron-mediated reactions have become vital tools for synthetic chemistry, particularly in asymmetric synthesis, metal-catalyzed processes, acid catalysis, and multicomponent reactions. As a result, boronic acids and related molecules have now evolved as major players in synthetic and medicinal chemistry. Moreover, their remnant electrophilic reactivity, even under physiological conditions, has allowed their incorporation in a growing number of bioactive molecules, including bortezomib, a clinically approved anticancer agent. Finally, the sensitive and selective binding of boronic acids to diols and carbohydrates has led to the development of a growing number of novel chemosensors for the detection, quantification, and imaging of glucose and other carbohydrates. There is no doubt that the chemistry of organoboron compounds will continue to expand into new discoveries and new applications in several fields of science.

The Stereochemistry of Organometallic Compounds. XXIX. Synthesis of Steroidal 1,4-Diphosphine, 1,3-Diphosphine and 1,6-Diphosphine and Their Evaluation as Ligands in Metal Catalyzed Asymmetric Synthesis

1987 ◽  
Vol 40 (6) ◽  
pp. 1083 ◽  
Author(s):  
RJ Thomson ◽  
WR Jackson ◽  
D Haarburger ◽  
EI Klabunovsky ◽  
VA Pavlov
Keyword(s):  
Asymmetric Synthesis ◽  
Asymmetric Hydrogenation ◽  
Organometallic Compounds ◽  
Carbon Bond ◽  
Bond Forming ◽  
Carbon Carbon Bond ◽  
Bond Forming Reactions ◽  
Hydrogenation Reactions ◽  
Metal Catalyzed ◽  
Asymmetric Carbon

The steroidal 1,4-diphosphines 3α- and 3β-diphenylphosphino-2a-(2'-diphenylphosphinoethyl)-5α-cholestanes and their 5H-benzo[b] phosphindole derivatives have been prepared and shown to be useful ligands in asymmetric hydrogenation reactions. Interestingly the 3α- and 3β-derivatives lead to opposing enantioselection preferences when used in these reactions. A steroidal 1,3-diphosphine, 3α-diphenylphosphino-2α-diphenylphosphinomethyl-5α-cholestane, has been prepared as a mixture containing some of the 3β-epimer. The 3α-1,3-diphosphine led to similar enantioselection in hydrogenation reactions as the 3α-1,4-diphosphine, and a model is proposed to explain the sense of the enantioselectivity in the 1,4- and 1,3-diphosphines. A steroidal 1,6-diphosphine has also been prepared but leads to lower optical yields in the hydrogenation reactions. These ligands have been shown to lead to only poor to moderate optical yields when used in asymmetric carbon-carbon bond forming reactions.

Asymmetric hydrogenation via architectural and functional molecular engineering

2001 ◽  
Vol 73 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Ryoji Noyori ◽  
Masatoshi Koizumi ◽  
Dai Ishii ◽  
Takeshi Ohkuma
Keyword(s):  
Asymmetric Synthesis ◽  
Nitro Group ◽  
Functional Group ◽  
Asymmetric Hydrogenation ◽  
Molecular Engineering ◽  
The Novel ◽  
Bifunctional Mechanism ◽  
Chiral Compounds ◽  
Halogen Atoms ◽  
Metal Ligand

RuCl2 (phosphine) 2 (1,2-diamine) complexes, coupled with an alkaline base in 2-propanol, allows for preferential hydrogenation of a C=O function over coexisting conjugated or nonconjugated C=C linkages, a nitro group, halogen atoms, and various heterocycles. The functional group selectivity is based on the novel metal-ligand bifunctional mechanism. The use of appropriate chiral diphosphines and diamines results in rapid and productive asymmetric hydrogenation of a range of aromatic, hetero-aromatic, and olefinic ketones. The versatility of this method is manifested by the asymmetric synthesis of various biologically significant chiral compounds.

Iridium-catalyzed acid-assisted asymmetric hydrogenation of oximes to hydroxylamines

Science ◽  
2020 ◽  
Vol 368 (6495) ◽  
pp. 1098-1102 ◽  
Author(s):  
Josep Mas-Roselló ◽  
Tomas Smejkal ◽  
Nicolai Cramer
Keyword(s):  
Room Temperature ◽  
Asymmetric Hydrogenation ◽  
Selective Reduction ◽  
Building Blocks ◽  
Efficient Catalyst ◽  
Cyclopentadienyl Ligand ◽  
Acidic Conditions ◽  
Asymmetric Hydrogenations ◽  
Metal Catalyzed ◽  
Oxygen Bond

Asymmetric hydrogenations are among the most practical methods for the synthesis of chiral building blocks at industrial scale. The selective reduction of an oxime to the corresponding chiral hydroxylamine derivative remains a challenging variant because of undesired cleavage of the weak nitrogen-oxygen bond. We report a robust cyclometalated iridium(III) complex bearing a chiral cyclopentadienyl ligand as an efficient catalyst for this reaction operating under highly acidic conditions. Valuable N-alkoxy amines can be accessed at room temperature with nondetected overreduction of the N‒O bond. Catalyst turnover numbers up to 4000 and enantiomeric ratios up to 98:2 are observed. The findings serve as a blueprint for the development of metal-catalyzed enantioselective hydrogenations of challenging substrates.

scholarly journals Fast Carbon Isotope Exchange of Carboxylic Acids Enabled by Organic Photoredox Catalysis

2020 ◽  
Author(s):  
Duanyang Kong ◽  
Maxime Munch ◽  
Qiqige Qiqige ◽  
Christopher Cooze ◽  
Benjamin Rotstein ◽  
...  
Keyword(s):  
Transition Metal ◽  
Carbon Isotope ◽  
Carboxylic Acids ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Reaction Times ◽  
Thermally Induced ◽  
Drug Molecules ◽  
Metal Catalyzed ◽  
Isotopic Incorporation

Carbazole/cyanobenzene photocatalysts promote the direct isotopic carboxylate exchange of C(sp3 )-acids with labelled CO2. Substrates that are not compatible with transition metal catalyzed degradation-reconstruction approaches or prone to thermally induced reversible decarboxylation undergo isotopic incorporation at room temperature in short reaction times. The radiolabelling of drug molecules and precursors with [11C]CO2 is demonstrated.

Microwave Assisted Green Synthesis of Benzimidazole Derivatives and Evaluation of Their Anticonvulsant Activity

2019 ◽  
Vol 6 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Biswa Mohan Sahoo ◽  
Bimal Krishna Banik ◽  
Mazaharunnisa ◽  
Naidu Srinivasa Rao ◽  
Bodapati Raju
Keyword(s):  
Reaction Time ◽  
Anticonvulsant Activity ◽  
Bioactive Molecules ◽  
High Yield ◽  
Benzimidazole Derivatives ◽  
Standard Drug ◽  
Drug Molecules ◽  
Microwave Reaction ◽  
Privileged Structure ◽  
Irradiation Technology

Background: Benzimidazole is the fused heterocyclic aromatic compound. It is an essential pharmacophore and privileged structure for the development of new drug molecules. These are bioactive molecules present in various anthelmintic drugs such as albendazole, mebendazole, parbendazole, triclabendazole etc. Methods: Benzimidazole derivatives are synthesized by reaction between orthophenylene diamine and anthranillic acid followed by acetylation in the presence of acetic anhydride. Finally, the acetylated products undergo Claisen-Schimdt condensation with various substituted benzaldehydes to produce corresponding benzimidazole derivatives or chalcones. Both conventional and microwave irradiation technology are followed to get the titled compounds. The titled compounds are screened for their anticonvulsant and neurotoxicity activity. Results: By the help of microwave synthesis, the yield of product was increased in less reaction time. So, it follows Green chemistry approach by making above reactions eco-friendly. Some of the compounds exhibited significant anticonvulsant activity as compared to standard drug. Conclusion: In the present investigation, we have synthesized novel benzimdazole derivatives with chalone moiety to improve the biological activity. The compounds were obtained under microwave reaction with high yield in a short reaction time.

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