Visible‐Light‐Induced C4‐Selective Functionalization of Pyridinium Salts with Cyclopropanols

2021 ◽  
Author(s):  
Mari Vellakkaran ◽  
Taehwan Kim ◽  
Sungwoo Hong
Keyword(s):  
Visible Light ◽  
Pyridinium Salts ◽  
Selective Functionalization

Dearomatization‐Enabled Visible‐Light‐Induced 1,2‐Alkylsulfonylation of Alkenes Using Sodium Sulfinates and Pyridinium Salts

2020 ◽  
Vol 362 (16) ◽  
pp. 3369-3373
Author(s):  
Yuan Yang ◽  
Chong‐Hui Xu ◽  
Fan Teng ◽  
Jin‐Heng Li
Keyword(s):  
Visible Light ◽  
Pyridinium Salts

Visible light induced 3-position-selective addition of arylpropiolic acids with ethers via C(sp3)–H functionalization

2020 ◽  
Vol 18 (17) ◽  
pp. 3258-3262
Author(s):  
Zi-juan Wan ◽  
Xiao-feng Yuan ◽  
Jun Luo
Keyword(s):  
Visible Light ◽  
Cyclic Ethers ◽  
Selective Functionalization ◽  
Decarboxylative Coupling ◽  
Selective Addition

Although the 2-position-selective decarboxylative coupling or addition of arylpropiolic acids with cyclic ethers has been intensively investigated, selective functionalization of arylpropiolic acids at the 3-position is still a big challenge.

A Frustrated Lewis Pair Solution to a Frustrating Problem: Mono-Selective Functionalization of C–F Bonds in Di- and Trifluoromethyl Groups

Synlett ◽  
2020 ◽  
Vol 31 (10) ◽  
pp. 933-937
Author(s):  
Rowan D. Young ◽  
Richa Gupta ◽  
Amit K. Jaiswal ◽  
Dipendu Mandal
Keyword(s):  
Nucleophilic Substitution ◽  
Functional Groups ◽  
Bond Activation ◽  
Pyridinium Salts ◽  
Selective Functionalization ◽  
Frustrated Lewis Pair ◽  
Hydrogenation Reactions ◽  
Trifluoromethyl Groups

Polyfluoromethyl groups generally suffer from over-reaction, where multiple C–F bonds are uncontrollably functionalized. The use of a frustrated Lewis pair (FLP)-mediated C–F bond activation permits selective monodefluorination through base capture of intermediate fluorocarbocations. FLP-mediated C–F bond activation can be applied to aromatic, heteroaromatic, or nonaromatic difluoro and trifluoromethyl groups to generate selectively fluoride-substituted phosphonium and pyridinium salts. These salts can be further functionalized by Wittig coupling, nucleophilic substitution, photoredox alkylation, nucleophilic transfer, or hydrogenation reactions to install a range of functional groups into the activated C–F position.1 Introduction2 Frustrated Lewis Pair C–F Activation3 Conclusion

scholarly journals Visible-Light-Mediated Amination of π-Nucleophiles with N-Aminopyridinium Salts

2019 ◽  
Author(s):  
Katarzyna Goliszewska ◽  
Katarzyna Rybicka-Jasińska ◽  
Jakub Szurmak ◽  
Dorota Gryko
Keyword(s):  
Visible Light ◽  
Carbonyl Compounds ◽  
Uv Light ◽  
Light Irradiation ◽  
Pyridinium Salts ◽  
Nitrenium Ions ◽  
Uv Light Irradiation

Under UV light irradiation <i>N</i>,<i>N</i>-(diphenylamino)pyridinium salts generate nitrenium ions. Herein, we report that in the presence of a photoredox catalyst nitrogen-centered radicals form which then react with enol equivalents to give amino carbonyl compounds in excellent yields.<br>

scholarly journals Visible-Light-Mediated Amination of π-Nucleophiles with N-Aminopyridinium Salts

2019 ◽  
Author(s):  
Katarzyna Goliszewska ◽  
Katarzyna Rybicka-Jasińska ◽  
Jakub Szurmak ◽  
Dorota Gryko
Keyword(s):  
Visible Light ◽  
Carbonyl Compounds ◽  
Uv Light ◽  
Light Irradiation ◽  
Pyridinium Salts ◽  
Nitrenium Ions ◽  
Uv Light Irradiation

Under UV light irradiation <i>N</i>,<i>N</i>-(diphenylamino)pyridinium salts generate nitrenium ions. Herein, we report that in the presence of a photoredox catalyst nitrogen-centered radicals form which then react with enol equivalents to give amino carbonyl compounds in excellent yields.<br>

scholarly journals Donor-Acceptor Pyridinium Salts for Photo-Induced Electron Transfer Driven Modification of Tryptophan in Peptides, Proteins, and Proteomes using Visible Light

2021 ◽  
Author(s):  
Caleb Hoopes ◽  
Francisco Garcia ◽  
Akash Sarkar ◽  
Nicholas Kuehl ◽  
David Barkan ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Chemical Reactivity ◽  
Live Cells ◽  
Quantum Yields ◽  
Cell Labelling ◽  
Pyridinium Salts ◽  
Donor Acceptor ◽  
Photo Induced Electron Transfer

Tryptophan (Trp) plays a variety of critical functional roles in protein biochemistry however, owing to its low natural frequency and poor nucleophilicity, the design of effective methods for both single protein bioconjugation at Trp as well as for in situ chemoproteomic profiling re-mains a challenge. Here, we report a method for covalent Trp modification that is suitable for both scenarios by invoking photo-induced electron transfer (PET) as a means of driving efficient reactivity. We have engineered biaryl N-carbamoyl pyridinium salts that possess a donor-acceptor relationship enabling optical triggering with visible light whilst simultaneously attenuating the probe’s photo-oxidation potential in order to prevent photodegradation. This probe was assayed against a small bank of eight peptides and proteins, where it was found that micromolar concentrations of probe and short irradiation times (10-60 min) with violet light enabled efficient reactivity towards surface exposed Trp residues. The carbamate transferring group can be used to transfer useful functional groups to proteins including affinity tags and click handles. DFT calculations and other mechanistic analyses reveal correlations between excited state lifetimes, relative fluorescent quantum yields, and chemical reactivity. Biotinylated and azide-functionalized pyridinium salts were used for Trp profiling in HEK293T lysates and in situ in HEK293T cells using 450 nm LED irradiation. Peptide level enrichment from live cell labelling experiments identified 290 Trp modifications, with an 82% selectivity for Trp modification over other π-amino acids; demonstrating the ability of this method to identify and quantify reactive Trp residues from live cells.

Photocatalyst-controlled and visible light-enabled selective oxidation of pyridinium salts

2021 ◽  
Author(s):  
Xiang-Jun Peng ◽  
Hai-Ping He ◽  
Qian Liu ◽  
Kun She ◽  
Bao-Qi Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Selective Oxidation ◽  
Pyridinium Salts
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