Dual NHC/Photoredox Catalysis for the Synthesis of β-CF3 (Hetero)Aryl Ketones

Synfacts ◽  
2020 ◽  
Vol 16 (10) ◽  
pp. 1180
Keyword(s):  
Photoredox Catalysis ◽  
Aryl Ketones

scholarly journals Asymmetric benzylic C(sp3)−H acylation via dual nickel and photoredox catalysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Leitao Huan ◽  
Xiaomin Shu ◽  
Weisai Zu ◽  
De Zhong ◽  
Haohua Huo
Keyword(s):  
Carboxylic Acids ◽  
Organic Synthesis ◽  
Late Stage ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Photoredox Catalysis ◽  
Mechanistic Studies ◽  
Cross Coupling Reaction ◽  
Aryl Ketones ◽  
Alkyl Benzenes

AbstractAsymmetric C(sp3)−H functionalization is a persistent challenge in organic synthesis. Here, we report an asymmetric benzylic C−H acylation of alkylarenes employing carboxylic acids as acyl surrogates for the synthesis of α-aryl ketones via nickel and photoredox dual catalysis. This mild yet straightforward protocol transforms a diverse array of feedstock carboxylic acids and simple alkyl benzenes into highly valuable α-aryl ketones with high enantioselectivities. The utility of this method is showcased in the gram-scale synthesis and late-stage modification of medicinally relevant molecules. Mechanistic studies suggest a photocatalytically generated bromine radical can perform benzylic C−H cleavage to activate alkylarenes as nucleophilic coupling partners which can then engage in a nickel-catalyzed asymmetric acyl cross-coupling reaction. This bromine-radical-mediated C−H activation strategy can be also applied to the enantioselective coupling of alkylarenes with chloroformate for the synthesis of chiral α-aryl esters.

Unlocking the Synthetic Potential of Light-Excited Aryl ketones – Applications in Direct Photochemistry and Photoredox Catalysis

Synlett ◽  
2021 ◽  
Author(s):  
Javier Mateos ◽  
Sara Cuadros ◽  
Alberto Vega-Penaloza ◽  
Luca Dell'Amico
Keyword(s):  
New Technologies ◽  
Diels Alder ◽  
Synthetic Methods ◽  
Photoredox Catalysis ◽  
New Family ◽  
Mechanistic Analysis ◽  
Aryl Ketones ◽  
The Way

In this account article, we summarize the contributions of our group to the field of photochemistry and photocatalysis. Our work deals with the development of novel synthetic methods based on the exploitation of photoexcited aryl ketones. The application of new technologies, such as microfluidic photoreactors (MFPs), have enhanced the synthetic performance and scalability of several photochemical methods i.e. Paternò–Büchi and photoenolization/Diels-Alder processes, while opening the way to unprecedented reactivity. Further, the careful mechanistic analysis of the developed methods has been instrumental to disclosing a new family of powerful organic photocatalyst able to mediate several thermodynamically extreme photoredox processes.

scholarly journals Benzylic C−H acylation by cooperative NHC and photoredox catalysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qing-Yuan Meng ◽  
Lena Lezius ◽  
Armido Studer
Keyword(s):  
Organic Molecules ◽  
Functional Group ◽  
Photoredox Catalysis ◽  
Diverse Range ◽  
Site Selectivity ◽  
Aryl Ketones ◽  
Direct Acylation ◽  
Selective Acylation ◽  
Site Selective ◽  
Complex Organic

AbstractMethods that enable site selective acylation of sp3 C-H bonds in complex organic molecules are not well explored, particularly if compared with analogous transformations of aromatic and vinylic sp2 C-H bonds. We report herein a direct acylation of benzylic C-H bonds by merging N-heterocyclic carbene (NHC) and photoredox catalysis. The method allows the preparation of a diverse range of benzylic ketones with good functional group tolerance under mild conditions. The reaction can be used to install acyl groups on highly functionalized natural product derived compounds and the C-H functionalization works with excellent site selectivity. The combination of NHC and photoredox catalysis offers options in preparing benzyl aryl ketones.

scholarly journals Cooperative NHC and Photoredox Catalysis for the Synthesis of β‐Trifluoromethylated Alkyl Aryl Ketones

2020 ◽  
Vol 59 (45) ◽  
pp. 19956-19960 ◽  
Author(s):  
Qing‐Yuan Meng ◽  
Nadine Döben ◽  
Armido Studer
Keyword(s):  
Photoredox Catalysis ◽  
Alkyl Aryl ◽  
Aryl Ketones

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.

The Merger of CF3SO2Na and Palladium Catalysis to Enable Decarboxylative Cross-Coupling for the Synthesis of Aromatic Ketones under Room Temperature

2021 ◽  
Author(s):  
Pan Xie ◽  
Cheng Xue ◽  
Cancan Wang ◽  
Dongdong Du ◽  
Sanshan Shi
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Palladium Catalysis ◽  
Cross Coupling ◽  
Boronic Acids ◽  
Aromatic Ketones ◽  
Aryl Ketones ◽  
Oxocarboxylic Acids

A CF3SO2Na/Pd(OAc)2 co-catalyzed strategy is developed to produce aryl ketones via visible-light-induced decarboxylative cross-coupling of α-oxocarboxylic acids and aryl boronic acids. This process was perfomed under air at room temperature,...

scholarly journals Tandem photoelectrochemical and photoredox catalysis for efficient and selective aryl halides functionalization by solar energy

Matter ◽  
2021 ◽  
Author(s):  
Ya-Jing Chen ◽  
Tao Lei ◽  
Hui-Lan Hu ◽  
Hao-Lin Wu ◽  
Shuai Zhou ◽  
...  
Keyword(s):  
Solar Energy ◽  
Aryl Halides ◽  
Photoredox Catalysis
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