scholarly journals Photoinitiated carbonyl-metathesis: deoxygenative reductive olefination of aromatic aldehydes via photoredox catalysis

2019 ◽  
Vol 10 (17) ◽  
pp. 4580-4587 ◽  
Author(s):  
Shun Wang ◽  
Nanjundappa Lokesh ◽  
Johnny Hioe ◽  
Ruth M. Gschwind ◽  
Burkhard König
Keyword(s):  
Aromatic Aldehydes ◽  
Photoredox Catalysis ◽  
Mcmurry Reaction ◽  
Carbonyl Olefination ◽  
Powerful Strategy

Carbonyl–carbonyl olefination, known as McMurry reaction, represents a powerful strategy for the construction of olefins.

scholarly journals Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

2015 ◽  
Vol 11 ◽  
pp. 1570-1582 ◽  
Author(s):  
David W Manley ◽  
John C Walton
Keyword(s):  
Organic Synthesis ◽  
Radical Anion ◽  
Radical Cations ◽  
Aromatic Aldehydes ◽  
Hydrogen Gas ◽  
Primary Amines ◽  
Tertiary Amines ◽  
Photoredox Catalysis ◽  
Enol Ethers ◽  
Cyclic Amines

Heterogeneous semiconductor photoredox catalysis (SCPC), particularly with TiO2, is evolving to provide radically new synthetic applications. In this review we describe how photoactivated SCPCs can either (i) interact with a precursor that donates an electron to the semiconductor thus generating a radical cation; or (ii) interact with an acceptor precursor that picks up an electron with production of a radical anion. The radical cations of appropriate donors convert to neutral radicals usually by loss of a proton. The most efficient donors for synthetic purposes contain adjacent functional groups such that the neutral radicals are resonance stabilized. Thus, ET from allylic alkenes and enol ethers generated allyl type radicals that reacted with 1,2-diazine or imine co-reactants to yield functionalized hydrazones or benzylanilines. SCPC with tertiary amines enabled electron-deficient alkenes to be alkylated and furoquinolinones to be accessed. Primary amines on their own led to self-reactions involving C–N coupling and, with terminal diamines, cyclic amines were produced. Carboxylic acids were particularly fruitful affording C-centered radicals that alkylated alkenes and took part in tandem addition cyclizations producing chromenopyrroles; decarboxylative homo-dimerizations were also observed. Acceptors initially yielding radical anions included nitroaromatics and aromatic iodides. The latter led to hydrodehalogenations and cyclizations with suitable precursors. Reductive SCPC also enabled electron-deficient alkenes and aromatic aldehydes to be hydrogenated without the need for hydrogen gas.

Studies on Ylides: Carbonyl Olefination with p-Chlorobenzylidenetriphenylphosphorane

1973 ◽  
Vol 28 (7-8) ◽  
pp. 475-477 ◽  
Author(s):  
P. S. Kendurkar ◽  
R. S. Tewari
Keyword(s):  
Nmr Spectra ◽  
Aromatic Aldehydes ◽  
Ir And Nmr Spectra ◽  
Carbonyl Olefination

Preparation of p-chlorobenzylidenetriphenylphosphorane and its carbonyl olefination with a series of substituted aromatic aldehydes and 9-fluorenone are described. IR and NMR spectra of the resulting olefins were studied. Acylation of p-chlorobenzyliden-etriphenylphosphorane afforded a new disubstituted ylide.

Organoboron Compounds in Visible Light-Driven Photoredox Catalysis

2021 ◽  
Vol 25 ◽  
Author(s):  
Tomasz Kliś ◽  
Marcin Kublicki
Keyword(s):  
Visible Light ◽  
Small Molecules ◽  
Dual Role ◽  
Photoredox Catalysis ◽  
Rapid Progress ◽  
Organoboron Compounds ◽  
Visible Light Driven ◽  
Photocatalytic Reactions ◽  
Powerful Strategy

: The increasing importance of visible light photoredox catalysis as a powerful strategy for the activation of small molecules, requires the development of new effective radical sources and photocatalysts. The unique properties of organoboron compounds have contributed significantly to the rapid progress of photocatalysis. Since the first work on the topic in 2005 many researchers have appreciated the role of boron-containing compounds in photocatalysis, and this is reflected in several publications. In this review, we highlight the utility of organoboron compounds in various photocatalytic reactions enabling the construction of carbon-carbon and carbon-heteroatom bonds. The dual role of organoboron compounds in photocatalysis is highlighted by their applications as reactants and as well as organic photocatalysts.

Combining Oxoammonium Cation Mediated Oxidation and Photoredox Catalysis for the Conversion of Aldehydes into Nitriles

Synlett ◽  
2018 ◽  
Vol 29 (16) ◽  
pp. 2185-2190 ◽  
Author(s):  
Nicholas Leadbeater ◽  
Jyoti Nandi ◽  
Mason Witko
Keyword(s):  
Visible Light ◽  
Nitrogen Source ◽  
Catalytic System ◽  
Aromatic Aldehydes ◽  
Ammonium Persulfate ◽  
Photoredox Catalysis ◽  
Mediated Oxidation

A method to oxidize aromatic aldehydes to nitriles has been developed. It involves a dual catalytic system of 4-acetamido-TEMPO and visible-light photoredox catalysis. The reaction is performed using ammonium persulfate as both the terminal oxidant and nitrogen source.

scholarly journals Eosin Y catalysed photoredox synthesis: a review

RSC Advances ◽  
2017 ◽  
Vol 7 (50) ◽  
pp. 31377-31392 ◽  
Author(s):  
Vishal Srivastava ◽  
Praveen P. Singh
Keyword(s):  
Organic Chemistry ◽  
Small Molecules ◽  
Eosin Y ◽  
Photoredox Catalysis ◽  
Powerful Strategy

In recent years, photoredox catalysis using eosin Y has come to the fore front in organic chemistry as a powerful strategy for the activation of small molecules.

Spin-Forbidden Excitation Enables Infrared Photoredox Catalysis

2020 ◽  
Author(s):  
Tomislav Rovis ◽  
Benjamin D. Ravetz ◽  
Nicholas E. S. Tay ◽  
Candice Joe ◽  
Melda Sezen-Edmonds ◽  
...  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Intersystem Crossing ◽  
Photoredox Catalysis ◽  
Infrared Irradiation ◽  
Triplet Excitation ◽  
New Family ◽  
Ir Light

We describe a new family of catalysts that undergo direct ground state singlet to excited state triplet excitation with IR light, leading to photoredox catalysis without the energy waste associated with intersystem crossing. The finding allows a mole scale reaction in batch using infrared irradiation.

Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage–Independent Activation of Strong C–O Bonds

2018 ◽  
Author(s):  
Erin Stache ◽  
Alyssa B. Ertel ◽  
Tomislav Rovis ◽  
Abigail G. Doyle
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups ◽  
Single Step ◽  
Direct Access ◽  
Photoredox Catalysis ◽  
Acyl Radical ◽  
Synthetic Strategy ◽  
Acyl Radicals ◽  
Benzyl Radicals ◽  
Aliphatic Carboxylic Acids

Alcohols and carboxylic acids are ubiquitous functional groups found in organic molecules that could serve as radical precursors, but C–O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen centered nucleophile. We first show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H-atom trapping to afford the deoxygenated product. Using the same method, we demonstrate access to synthetically versatile acyl radicals which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge new C–O, C–N and C–C bonds in a single step.

Regioselective C3-H Trifluoromethylation of 2H-Indazole Under Transition-Metal-Free Photoredox Catalysis

2019 ◽  
Author(s):  
Arumugavel Murugan ◽  
Venkata Nagarjuna Babu ◽  
Nagaraj Sabarinathan ◽  
Sharada Duddu. S
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Practical Approach ◽  
Hypervalent Iodine ◽  
Radical Mechanism ◽  
Photoredox Catalysis ◽  
Metal Free

Here we report a visible-light-promoted metal-free regioselective C3-H trifluoromehtylation reaction that proceeds via radical mechanism and which supported by control experiments. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the present trifluoromethylation reaction and synthesis of a library of trifluoromethylated indazoles.

Lysosome Targeting Chimeras (LYTACs) for the Degradation of Secreted and Membrane Proteins

2019 ◽  
Author(s):  
Steven Banik ◽  
Kayvon Pedram ◽  
Simon Wisnovsky ◽  
Nicholas Riley ◽  
Carolyn Bertozzi
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Membrane Proteins ◽  
Growth Factor Receptor ◽  
Basic Research ◽  
Biochemical Pathway ◽  
Programmed Death Ligand 1 ◽  
Programmed Death ◽  
A Cell ◽  
Epidermal Growth ◽  
Powerful Strategy

<p>Targeted protein degradation is a powerful strategy to address the canonically undruggable proteome. However, current technologies are limited to targets with cytosolically-accessible and ligandable domains. Here, we designed and synthesized conjugates capable of binding both a cell surface lysosome targeting receptor and the extracellular domain of a target protein. These lysosome targeting chimeras (LYTACs) consist of an antibody fused to agonist glycopeptide ligands for the cation-independent mannose-6-phosphate receptor (CI-M6PR). LYTACs enabled a CRISPRi knockdown screen revealing the biochemical pathway for CI-M6PR-mediated cargo internalization. We demonstrated that LYTACs mediate efficient degradation of Apolipoprotein-E4, epidermal growth factor receptor (EGFR), CD71, and programmed death-ligand 1 (PD-L1). LYTACs represent a modular strategy for directing secreted and membrane proteins for degradation in the context of both basic research and therapy. <b></b></p>

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