scholarly journals Catalytic enantioselective reductive domino alkyl arylation of acrylates via nickel/photoredox catalysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pengcheng Qian ◽  
Haixing Guan ◽  
Yan-En Wang ◽  
Qianqian Lu ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Visible Light ◽  
Nickel Catalyst ◽  
Alkyl Radical ◽  
Reductive Elimination ◽  
Important Class ◽  
Organometallic Reagents ◽  
Mild Conditions ◽  
Key Steps ◽  
Carbonyl Radical

AbstractNonsteroidal anti-inflammatory drug derivatives (NSAIDs) are an important class of medications. Here we show a visible-light-promoted photoredox/nickel catalyzed approach to construct enantioenriched NSAIDs via a three-component alkyl arylation of acrylates. This reductive cross-electrophile coupling avoids preformed organometallic reagents and replaces stoichiometric metal reductants by an organic reductant (Hantzsch ester). A broad range of functional groups are well-tolerated under mild conditions with high enantioselectivities (up to 93% ee) and good yields (up to 90%). A study of the reaction mechanism, as well as literature precedence, enabled a working reaction mechanism to be presented. Key steps include a reduction of the alkyl bromide to the radical, Giese addition of the alkyl radical to the acrylate and capture of the α-carbonyl radical by the enantioenriched nickel catalyst. Reductive elimination from the proposed Ni(III) intermediate generates the product and forms Ni(I).

scholarly journals Application of visible-light photosensitization to form alkyl-radical-derived thin films on gold

2017 ◽  
Vol 8 ◽  
pp. 1863-1877 ◽  
Author(s):  
Rashanique D Quarels ◽  
Xianglin Zhai ◽  
Neepa Kuruppu ◽  
Jenny K Hedlund ◽  
Ashley A Ellsworth ◽  
...  
Keyword(s):  
Thin Films ◽  
Visible Light ◽  
Alkyl Radical ◽  
Organic Molecules ◽  
Film Structure ◽  
Small Organic Molecules ◽  
Alkyl Radicals ◽  
Mild Conditions ◽  
Radical Generation ◽  
First Time

Visible-light irradiation of phthalimide esters in the presence of the photosensitizer [Ru(bpy)3]2+ and the stoichiometric reducing agent benzyl nicotinamide results in the formation of alkyl radicals under mild conditions. This approach to radical generation has proven useful for the synthesis of small organic molecules. Herein, we demonstrate for the first time the visible-light photosensitized deposition of robust alkyl thin films on Au surfaces using phthalimide esters as the alkyl radical precursors. In particular, we combine visible-light photosensitization with particle lithography to produce nanostructured thin films, the thickness of which can be measured easily using AFM cursor profiles. Analysis with AFM demonstrated that the films are robust and resistant to mechanical force while contact angle goniometry suggests a multilayered and disordered film structure. Analysis with IRRAS, XPS, and TOF SIMS provides further insights.

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff ◽  
Frank Glorius
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

Enantioselective Radical Functionalization of Imines and Iminium Intermediates via Visible Light Photoredox Catalysis

Synthesis ◽  
2020 ◽  
Author(s):  
Jia-Jia Zhao ◽  
Hong-Hao Zhang ◽  
Shouyun Yu
Keyword(s):  
Visible Light ◽  
Asymmetric Synthesis ◽  
Carbonyl Compounds ◽  
Asymmetric Reduction ◽  
Chemical Transformations ◽  
Photoredox Catalysis ◽  
Radical Coupling ◽  
Mild Conditions ◽  
Iminium Ions ◽  
Radical Functionalization

Visible light photoredox catalysis has recently emerged as a powerful tool for the development of new and valuable chemical transformations under mild conditions. Visible-light promoted enantioselective radical transformations of imines and iminium intermediates provide new opportunities for the asymmetric synthesis of amines and asymmetric β-functionalization of unsaturated carbonyl compounds. In this review, the advance in the catalytic asymmetric radical functionalization of imines, as well as iminium intermediates, are summarized. 1 Introduction 2 The enantioselective radical functionalization of imines 2.1 Asymmetric reduction 2.2 Asymmetric cyclization 2.3 Asymmetric addition 2.4 Asymmetric radical coupling 3 The enantioselective radical functionalization of iminium ions 3.1 Asymmetric radical alkylation 3.2 Asymmetric radical acylation 4 Conclusion

D–π–A-type triphenylamine dye covalent-functionalized g-C3N4 for highly efficient photocatalytic hydrogen evolution

2020 ◽  
Vol 10 (6) ◽  
pp. 1609-1618 ◽  
Author(s):  
Chao Zhang ◽  
Jiandong Liu ◽  
Xingliang Liu ◽  
Shiai Xu
Keyword(s):  
Reaction Mechanism ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Light Irradiation ◽  
Photocatalytic Hydrogen Evolution ◽  
Highly Efficient

Reaction mechanism for the higher photocatalytic performance of H2 production of g-C3N4NSs/TC1 under visible light irradiation (λ ≥ 400 nm).

Visible-Light-Mediated Tandem Sulfonylation/Cyclization of Vinyl Azides with Sulfonyl Hydrazines for the Synthesis of 6-(Sulfonylmethyl)phenanthridines under Mild Conditions

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 955-960 ◽  
Author(s):  
Liu-Liang Mao ◽  
Li-Xia Quan ◽  
Xian-Hong Zhu ◽  
Cong-Bin Ji ◽  
An-Xi Zhou ◽  
...  
Keyword(s):  
Visible Light ◽  
Mild Conditions ◽  
Simple Strategy ◽  
Vinyl Azides

A visible-light-mediated tandem sulfonylation/cyclization of vinyl azides with sulfonyl hydrazines was developed that provides an efficient and simple strategy for the synthesis of valuable 6-(sulfonylmethyl)phenanthridines with a broad substrate scope and satisfactory yields under mild conditions.

Visible light-photocatalysed carbazole synthesis via a formal (4+2) cycloaddition of indole-derived bromides and alkynes

2016 ◽  
Vol 52 (29) ◽  
pp. 5128-5131 ◽  
Author(s):  
Zhi-Guang Yuan ◽  
Qiang Wang ◽  
Ang Zheng ◽  
Kai Zhang ◽  
Liang-Qiu Lu ◽  
...  
Keyword(s):  
Visible Light ◽  
Mild Conditions ◽  
Wide Range

We have developed an unprecedented route to carbazole by a visible light-photocatalysed formal (4+2) cycloaddition of indole-derived bromides and alkynes. Using this method, a wide range of highly functionalised carbazoles were produced in good yields under mild conditions.

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