Visible-Light-Promoted [2 + 2 + 2] Cyclization of Alkynes with Nitriles to Pyridines Using Pyrylium Salts as Photoredox Catalysts

Wang, Kuai; Meng, Ling‐Guo; Wang, Lei

doi:10.1021/acs.orglett.7b00292

Cited by 49 publications

(28 citation statements)

References 58 publications

(26 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Pyrylium‐based small‐molecule compounds have been used extensively as photocatalysts or synthetic intermediates . However, to our knowledge, pyrylium‐based porous polymers have never been reported.…”

Section: Methodsmentioning

confidence: 99%

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO₂Conversion

Yang

Chen

et al. 2019

Angewandte Chemie

View full text Add to dashboard Cite

Progress toward the preparation of porous organic polymers (POPs) with task-specific functionalities has been exceedingly slow-especially where polymers containing lowoxidation phosphorus in the structure are concerned. At wostep topotactic pathway for the preparation of phosphabenzene-based POPs (Phos-POPs) under metal-free conditions is reported, without the use of unstable phosphorus-based monomers.T he synthetic route allows additional functionalities to be introduced into the porous polymer framework with ease.A sa ne xample,p artially fluorinated Phos-POPs (F-Phos-POPs) were obtained with as urface area of up to 591 m 2 g À1 .A fter coordination with Ru species,aRu/F-Phos-POPs catalyst exhibited high catalytic efficiency in the formylation of amines (turnover frequency up to 204 h À1 ) using aC O 2 /H 2 mixture,i nc omparison with the non-fluorinated analogue (43 h À1 )and aAu/TiO 2 heterogeneous catalysts reported previously (< 44 h À1 ). This work describes apractical method for synthesis of porous organic phosphorus-based polymers with applications in transition-metal-based heterogeneous catalysis.Organophosphorus compounds have emerged as powerful organocatalysts [1][2][3][4] and they are the ligands of choice for an umber of transition-metal-catalyzed processes. [5][6][7][8] In general, phosphine-containing catalysts are used mainly in homogeneous processes,w here they exhibit excellent catalytic activities and selectivities.N evertheless,h eterogeneous phosphine-based catalysts are more desirable for industrial applications because it is more convenient to recover and recycle them. However,o nly af ew examples of heterogeneous phosphine-based catalytic systems have been reported to date. [9][10][11][12][13] Fore xample,X iao et al. reported as eries of diphosphine-ligand-containing porous frameworks obtained by polymerization of the vinyl-functionalized diphosphine monomers.T hese materials demonstrated superior catalytic performance in the hydroformylation of alkenes after treatment with Rh species. [12] Mesoporous poly(triphenylphosphine) with azo functionality (poly(PPh 3 )-azo) was synthesized by oxidative polymerization of aP ( m-NH 2 Ph) 3 monomer. After coordination with metal ions (for example,R u 3+ and Ag + ), the resulting metalated poly(PPh 3 )-azo catalysts mediated CO 2 conversion reactions efficiently. [13] Despite the progress made,anumber of obvious drawbacks still need to be addressed:1 )tedious synthetic processes under an inert atmosphere are generally required for the preparation of vinyl-or amino-group-functionalizedp hosphine monomers (Scheme 1);2 )limited synthetic methods can be used for polymer construction because of the poor compatibility and stability of the phosphine monomers under harsh reaction conditions,asw ell as difficulties associated with the removal of metal catalysts that are strongly coordinated by phosphine ligands;3 )the introduction of additional functionalities into the polymer backbone is difficult by monomer design and synthesis,o rb yp ost-synthetic func...

show abstract

Section: Methodsmentioning

confidence: 99%

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO₂Conversion

Yang

Chen

et al. 2019

Angewandte Chemie

View full text Add to dashboard Cite

show abstract

“…Pyridine core is widespread in many bioactive compounds [1,2,3]. The versatile methodology employing visible-light-promoted [2 + 2 + 2] cyclization of alkynes with nitriles to pyridines recently has been described by Wang and Meng group [39]. Using pyrylium salt 8d as photoredox catalysts, various 2,3,6-trisubstituted pyridines 47 can be prepared under blue LED irradiation.…”

Section: Application Of Visible-light-mediated Catalysis In Synthementioning

confidence: 99%

Recent Advances on Metal-Free, Visible-Light- Induced Catalysis for Assembling Nitrogen- and Oxygen-Based Heterocyclic Scaffolds

2019

View full text Add to dashboard Cite

Heterocycles are important class of structures, which occupy a major space in the domain of natural and bioactive compounds. For this reason, development of new synthetic strategies for their controllable synthesis became of special interests. The development of novel photoredox systems with wide-range application in organic synthesis is particularly interesting. Organic dyes have been widely applied as photoredox catalysts in organic synthesis. Their low costs compared to the typical photocatalysts based on transition metals make them an excellent alternative. This review describes proceedings since 2015 in the area of application of metal-free, visible-light-mediated catalysis for assembling various heterocyclic scaffolds containing five- and six-membered rings bearing nitrogen and oxygen heteroatoms.

show abstract

“…Acetonitrile was reacted with arylacetylenes using triarylpyrylium salts as photosensitizers to give trisubstituted pyridines in 40-69% yields (Scheme 37). 194 Lewis acid catalyzed protocols have been successfully used with N-EWG ynamides (EWG = electronwithdrawing group) to give 2,4-diaminopyridines (Scheme 37). 195,196…”

Section: Review Syn Thesismentioning

confidence: 99%

“…Scheme 36Metal-catalyzed cyclotrimerizations to give pyridine derivatives(Diversi et al 1987;183 Sugiyama et al 2011;184 Fischer et al 2012;193 McIver et al 2008;186 Staudaher et al 2014;189 Richard et al 2014190 ) Non-metal-catalyzed cyclotrimerizations with alkynes (Wang et al 2017;194 Wang et al2016 195 ) …”

mentioning

confidence: 99%

Acetonitrile as a Building Block and Reactant

Hoff

2018

Synthesis

View full text Add to dashboard Cite

Acetonitrile is popular as a solvent for performing organic reactions, as a ligand in inorganic chemistry, as a mobile phase in chromatography, and as an electrolyte solvent in dye-sensitized solar cells. This is mainly due to its ability to dissolve both polar and nonpolar components. However, acetonitrile is also a valuable building block allowing atom-efficient transformations in synthetic organic chemistry. The aim of this review is to highlight synthetic transformations using acetonitrile, covering both classical approaches and modern strategies proceeding through radical intermediates or mediated by metal catalysis. Besides showcasing synthetic protocols useful for acetonitrile and analogues, warnings for when not to use acetonitrile as a solvent are also provided.1 Introduction2 Fundamental Reactions with Acetonitrile3 Cyanomethylation of Non-Aromatics4 The Acetonitrile Nitrogen as a Nucleophile5 The Blaise Reaction6 Synthesis of Pyridines7 Other Cyclization Reactions8 Cyanomethylation of Arenes and Heteroarenes9 Acetylation of Arenes Using Acetonitrile10 Synthesis of N-Arylacetamides11 Cyanation Using Acetonitrile as a Cyanide Source12 When To Avoid Acetonitrile as a Solvent13 Conclusion

show abstract

Visible-Light-Promoted [2 + 2 + 2] Cyclization of Alkynes with Nitriles to Pyridines Using Pyrylium Salts as Photoredox Catalysts

Cited by 49 publications

References 58 publications

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO₂Conversion

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO₂Conversion

Recent Advances on Metal-Free, Visible-Light- Induced Catalysis for Assembling Nitrogen- and Oxygen-Based Heterocyclic Scaffolds

Acetonitrile as a Building Block and Reactant

Contact Info

Product

Resources

About

Visible-Light-Promoted [2 + 2 + 2] Cyclization of Alkynes with Nitriles to Pyridines Using Pyrylium Salts as Photoredox Catalysts

Cited by 49 publications

References 58 publications

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO2Conversion

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO2Conversion

Recent Advances on Metal-Free, Visible-Light- Induced Catalysis for Assembling Nitrogen- and Oxygen-Based Heterocyclic Scaffolds

Acetonitrile as a Building Block and Reactant

Contact Info

Product

Resources

About

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO₂Conversion

Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO₂Conversion