Visible-Light-Promoted C2 Trifluoromethylation of Quinoline N-Oxides

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 219-226 ◽  
Author(s):  
Ce Liang ◽  
Wang-Tao Zhuo ◽  
Yan-Ning Niu ◽  
Guo-Lin Gao
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Room Temperature ◽  
Efficient Synthesis ◽  
Mechanistic Studies ◽  
Reaction Proceeds

A photoredox catalytic strategy has been described for the direct C2 trifluoromethylation of quinoline N-oxides. This reaction is compatible with a range of synthetically relevant functional groups for providing efficient synthesis of a variety of C2 trifluoromethyl quinoline N-oxides at room temperature. Mechanistic studies indicated that the reaction proceeds via a radical pathway.

Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

2019 ◽  
Author(s):  
Marharyta V. Laktsevich-Iskryk ◽  
Nastassia A. Varabyeva ◽  
Volha V. Kazlova ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Ring Opening ◽  
Radical Intermediates ◽  
Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds <i>via</i> radical intermediates and tolerates various functional groups.

Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

2019 ◽  
Author(s):  
Marharyta V. Laktsevich-Iskryk ◽  
Nastassia A. Varabyeva ◽  
Volha V. Kazlova ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Ring Opening ◽  
Radical Intermediates ◽  
Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds <i>via</i> radical intermediates and tolerates various functional groups.

A Visible Light Photoredox Catalysed Radical Pictet-Spengler Reaction

2020 ◽  
Vol 73 (3) ◽  
pp. 189
Author(s):  
Theerada Seehamongkol ◽  
Tyra H. Horngren ◽  
Mohammed A. M. Alhajji ◽  
Joshua Almond-Thynne ◽  
Milena L. Czyz ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Photoredox Catalysis ◽  
Thermal Transformations ◽  
Complementary Method ◽  
Reaction Proceeds ◽  
Radical Approach

A methodology for a radical Pictet–Spengler reaction promoted by visible light photoredox catalysis is described. This strategy furnishes tetrahydroisoquinoline derivatives bearing electron poor and electron rich substituents. The reaction proceeds at room temperature and with excellent regioselectivity for the 6-endo intramolecular cyclisation. This radical approach provides a complementary method for the synthesis of the tetrahydroisoquinoline scaffold with substitution patterns inaccessible via established thermal transformations.

Visible-Light Photoredox-Catalyzed Cascade Reaction for the Synthesis of Pyrrolo[2,1-a]isoquinoline-Substituted Phosphonates

Synthesis ◽  
2018 ◽  
Vol 51 (02) ◽  
pp. 522-529 ◽  
Author(s):  
Deqing Shi ◽  
Lingna Wang ◽  
Tiancong Ma ◽  
Mingming Qiao ◽  
Qiangxian Wu ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Room Temperature ◽  
Cascade Reaction ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Oxidative Aromatization ◽  
Activated Olefins ◽  
Catalyzed Oxidation

A visible-light photoredox-catalyzed oxidation/[3+2] cycloaddition/oxidative aromatization cascade reaction of [(3,4-dihydroisoquinolin-2(1H)-yl)methyl]phosphonates and activated olefins or alkynes for the efficient synthesis of potentially biological active pyrrolo[2,1-a]isoquinoline-substituted phosphonates was developed. This transformation features mild reaction conditions (i.e., visible light irradiation, room temperature), molecular oxygen (O2) as a green oxidant, simple ‘one-pot’ operation.

Brønsted acid cocatalysis in photocatalytic intramolecular coupling of tertiary amines: efficient synthesis of 2-arylindols

2016 ◽  
Vol 14 (31) ◽  
pp. 7447-7450 ◽  
Author(s):  
Xiaoqian Yuan ◽  
Xinxin Wu ◽  
Shupeng Dong ◽  
Guibing Wu ◽  
Jinxing Ye
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Bronsted Acid ◽  
Tertiary Amines ◽  
Brønsted Acid ◽  
Efficient Synthesis ◽  
Unsaturated Ketones ◽  
Brönsted Acid

We report herein a highly efficient intramolecular coupling reaction of tertiary amines and ketones (α,β-unsaturated ketones) by using a Brønsted acid as a cocatalyst, affording 2-arylindols in good to excellent yields (up to 92%) under visible light irradiation at room temperature.

Aliphatic Radical Relay Heck Reaction at Unactivated C(sp3)–H Sites of Alcohols

2018 ◽  
Author(s):  
Padon Chuentragool ◽  
Dongari Yadagiri ◽  
Taiki Morita ◽  
Sumon Sarkar ◽  
Marvin Parasram ◽  
...  
Keyword(s):  
Visible Light ◽  
Heck Reaction ◽  
Room Temperature ◽  
Halogen Atom ◽  
Organic Molecules ◽  
Alkyl Halides ◽  
Aliphatic Alcohols ◽  
Aliphatic Radical ◽  
Reaction Proceeds

<div>The Mizoroki−Heck reaction is one of the most efficient methods for alkenylation of</div><div>aryl, vinyl, and alkyl halides. Due to its innate nature, this protocol requires the employment of compounds possessing a halogen atom at the site of functionalization. However, the accessibility of organic molecules possessing a halogen atom at a particular site in aliphatic systems is extremely limited. Thus, a protocol that would allow a Heck reaction to occur at a specific non-functionalized C(sp3)−H site would be highly desirable.</div><div>Here, we report a radical relay Heck reaction which allows for a selective remote</div>alkenylation of aliphatic alcohols at unactivated β-, γ- and δ-C(sp3 20 )–H sites. The use of easily installable/removable Si-based auxiliary enables selective I-atom/radical translocation events at remote C−H sites followed by the Heck reaction. Notably, the reaction proceeds smoothly under mild visible light-mediated conditions at room temperature, producing highly modifiable and valuable alkenol products from readily available alcohols feedstocks. <br>

Visible-light-activated copper(i) catalyzed oxidative Csp–Csp cross-coupling reaction: efficient synthesis of unsymmetrical conjugated diynes without ligands and base

2016 ◽  
Vol 18 (16) ◽  
pp. 4526-4530 ◽  
Author(s):  
Arunachalam Sagadevan ◽  
Ping-Chiang Lyu ◽  
Kuo Chu Hwang
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Terminal Alkynes ◽  
Efficient Synthesis ◽  
Cross Coupling Reaction ◽  
Conjugated Diynes

An efficient and eco-friendly approach to Csp–Csp cross-coupling of terminal alkynes for the construction of unsymmetrical conjugated diynes via a visible-light-induced CuCl catalysed process at room temperature is described.

Metal-Free Regioselective Alkylation of Imidazo[1,2-a]pyridines with N-Hydroxyphthalimide Esters under Organic Photoredox Catalysis

Synlett ◽  
2020 ◽  
Vol 31 (04) ◽  
pp. 363-368 ◽  
Author(s):  
Can Jin ◽  
Bin Sun ◽  
Tengwei Xu ◽  
Liang Zhang ◽  
Rui Zhu ◽  
...  
Keyword(s):  
Visible Light ◽  
Carboxylic Acids ◽  
Room Temperature ◽  
Eosin Y ◽  
Photoredox Catalysis ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Regioselective Alkylation ◽  
Decarboxylative Coupling ◽  
Aliphatic Carboxylic Acids

A visible-light-induced direct C–H alkylation of imidazo[1,2-a]pyridines has been developed. It proceeds at room temperature by employing inexpensive Eosin Y as a photocatalyst and alkyl N-hydroxyphthalimide (NHP) esters as alkylation reagents. A variety of NHP esters derived from aliphatic carboxylic acids (primary, secondary, and tertiary) were tolerated in this protocol, giving the corresponding C-5-alkylated products in moderate to excellent yields. Mechanistic studies indicate that a radical decarboxylative coupling pathway was involved in this process.

scholarly journals Visible-Light Photoredox-Catalyzed C–O Bond Cleavage of Diaryl Ethers by Acridinium Photocatalysts at Room Temperature

2020 ◽  
Author(s):  
Fang-Fang Tan ◽  
Xiao-Ya He He ◽  
Wan-Fa Tian ◽  
Yang Li
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Acid Catalysis ◽  
Bond Cleavage ◽  
Diphenyl Ether ◽  
Mechanistic Studies ◽  
Electrophilic Attack ◽  
One Pot ◽  
Diaryl Ethers ◽  
Diaryl Ether

Abstract We have developed visible-light photoredox-catalyzed C–O bond cleavage of diaryl ethers by an acidolysis with an aryl car-boxylic acid and a following one-pot hydrolysis. Two phenols are obtained from a diaryl ether at room temperature. The aryl carboxylic acid used for the acidolysis can be recovered. The key to success of the acidolysis is merging visible-light photore-dox catalysis with a new acridinium photocatalyst and Lewic acid catalysis with Cu(TMHD)2. Preliminary mechanistic studies indicate that the catalytic cycle occurs via a rare selective electrophilic attack of the generated aryl carboxylic radical on the electron-rich aryl ring of diphenyl ether. This transformation is applied to a gram-scale reaction and the model of 4-O-5 lignin linkages.

scholarly journals Synthesis of aryl sulfides via radical–radical cross coupling of electron-rich arenes using visible light photoredox catalysis

2018 ◽  
Vol 14 ◽  
pp. 2520-2528 ◽  
Author(s):  
Amrita Das ◽  
Mitasree Maity ◽  
Simon Malcherek ◽  
Burkhard König ◽  
Julia Rehbein
Keyword(s):  
Visible Light ◽  
Experimental Evidence ◽  
Blue Light ◽  
Room Temperature ◽  
Cross Coupling ◽  
Light Irradiation ◽  
Coupling Mechanism ◽  
Photoredox Catalysis ◽  
Reaction Proceeds ◽  
Aryl Sulfides

Electron-rich arenes react with aryl and alkyl disulfides in the presence of catalytic amounts of [Ir(dF(CF3)ppy)2(dtbpy)]PF6 and (NH4)2S2O8 under blue light irradiation to yield arylthiols. The reaction proceeds at room temperature and avoids the use of prefunctionalized arenes. Experimental evidence suggests a radical–radical cross coupling mechanism.

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