I2–DMSO–PTSA: a simple and metal free oxidative cross coupling of imidazo[1,2-a]pyridines and methylketones

RSC Advances ◽  
2015 ◽  
Vol 5 (25) ◽  
pp. 19418-19425 ◽  
Author(s):  
Madhu Chennapuram ◽  
Narender Reddy Emmadi ◽  
Chiranjeevi Bingi ◽  
Krishnaiah Atmakur
Keyword(s):  
Cross Coupling ◽  
Methyl Ketones ◽  
Simple Metal ◽  
One Pot ◽  
Metal Free

A simple, metal free and selective oxidative cross-coupling promoted by I2–DMSO in presence of PTSA has been developed with the use of imidazo[1,2-a]pyridines (1) and methyl ketones (2) to access 3 in a one pot reaction.

Reactions of Methyl Ketones and (Hetero)arylcarboxamides with N,N-Dimethylacetamide Dimethyl Acetal. A Simple Metal-Free Synthesis of 2,4,6-Trisubstituted Pyridines

2015 ◽  
Vol 68 (2) ◽  
pp. 184 ◽  
Author(s):  
Benjamin Prek ◽  
Uroš Grošelj ◽  
Marta Kasunič ◽  
Silvo Zupančič ◽  
Jurij Svete ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Single Crystal ◽  
Ammonium Acetate ◽  
Dimethyl Acetal ◽  
Methyl Ketones ◽  
Closed Vessel ◽  
Simple Metal ◽  
One Pot ◽  
X Ray ◽  
Metal Free

Two metal-free syntheses of 2,4,6-trisubstituted pyridines 10a–m and 16a–j are described. N,N,6-Trimethyl-4-(substituted)pyridin-2-amines 10 were prepared from aryl or heteroaryl methyl ketones which were transformed with N,N-dimethylacetamide dimethyl acetal (DMADMA) into enaminones 4a–m, followed by treatment with ammonium acetate to give (Z)-3-amino-1-(substituted)but-2-en-1-ones 5a–m. These were treated with DMADMA under microwave irradiation in a closed vessel at 130°C, to give via intermediates 7–9 the final products 10a–m. N2,N2,N4,N4-Tetramethyl-6-(substituted) pyridine-2,4-diamines 16a–j were prepared in a one-pot synthesis from the corresponding carboxamides 11a–j by treatment with an excess of DMADMA in a closed vessel under microwave irradiation to give via intermediates 12a–j to 15a–j the final products 16a–j. X-Ray single crystal diffractometry studies of the enaminones 5c, 5g, 5i, 5j, and 5m and 2,4,6-trisubstituted pyridines 16a, 16b, 16g, 16i, and 16j were consistent with the expected structures.

A Simple Metal-free Synthesis of 2,4,5-Trisubstituted Pyridines and Pyridine N-Oxides by [2+2] Cycloaddition of Enaminones to Propyne Iminium Salts

2014 ◽  
Vol 69 (5) ◽  
pp. 554-566 ◽  
Author(s):  
Jure Bezenšek ◽  
Benjamin Prek ◽  
Uroš Grošelj ◽  
Amalija Golobič ◽  
Katarina Stare ◽  
...  
Keyword(s):  
Dimethyl Acetal ◽  
Methyl Ketones ◽  
Simple Metal ◽  
One Pot ◽  
Alkyl Aryl ◽  
Metal Free ◽  
Iminium Salts

Herein a simple one-pot metal-free synthesis of 2,4,5-trisubstituted pyridines and pyridine Noxides by [2+2] cycloaddition of enaminones, which are prepared in situ from alkyl, aryl and heteroaryl methyl ketones using N,N-dimethylformamide dimethyl acetal (DMFDMA), and propyne iminium salts as electron-poor acetylenes, is described.

Metal-Free Photoredox-Catalyzed C–H/C–H Coupling of Arenes Enabled by Interrupted Pummerer Activation

2019 ◽  
Author(s):  
Miles Aukland ◽  
Mindaugas Šiaučiulis ◽  
Adam West ◽  
Gregory Perry ◽  
David Procter
Keyword(s):  
Natural Product ◽  
Selective Reduction ◽  
Cross Coupling ◽  
One Pot ◽  
Complex Molecules ◽  
Pummerer Reaction ◽  
Metal Free ◽  
Bond Forming ◽  
Coupling Partner ◽  
Bioactive Natural Product

<p>Aryl–aryl cross-coupling constitutes one of the most widely used procedures for the synthesis of high-value materials, ranging from pharmaceuticals to organic electronics and conducting polymers. The assembly of (hetero)biaryl scaffolds generally requires multiple steps; coupling partners must be functionalized before the key bond-forming event is considered. Thus, the development of selective C–H arylation processes in arenes, that side-step the need for prefunctionalized partners, is crucial for streamlining the construction of these key architectures. Here we report an expedient, one-pot assembly of (hetero)biaryl motifs using photocatalysis and two non-prefunctionalized arene partners. The approach is underpinned by the activation of a C–H bond in an arene coupling partner using the interrupted Pummerer reaction. A unique pairing of the organic photoredox catalyst and the intermediate dibenzothiophenium salts enables highly selective reduction in the presence of sensitive functionalities. The utility of the metal-free, one-pot strategy is exemplified by the synthesis of a bioactive natural product and the modification of complex molecules of societal importance.</p>

scholarly journals Metal-free and solvent-free synthesis of m-terphenyls through tandem cyclocondensation of aryl methyl ketones with triethyl orthoformate

RSC Advances ◽  
2020 ◽  
Vol 10 (20) ◽  
pp. 12113-12118 ◽  
Author(s):  
Xiaoqin Xiao ◽  
Juan Luo ◽  
Zongjie Gan ◽  
Wengao Jiang ◽  
Qiang Tang
Keyword(s):  
Solvent Free ◽  
Triethyl Orthoformate ◽  
Tandem Reaction ◽  
Methyl Ketones ◽  
One Pot ◽  
Metal Free ◽  
Solvent Free Synthesis ◽  
Aryl Methyl

A facile metal-free and solvent-free benzannulation was developed for the construction of m-terphenyl derivatives starting from aryl methyl ketones and triethyl orthoformate. This is a tandem reaction which merged six steps into one-pot procedure.

Transition-metal-free cross-coupling of thioethers with aryl(cyano)iodonium triflates: a facile and efficient method for the one-pot synthesis of thiocyanates

2015 ◽  
Vol 51 (33) ◽  
pp. 7180-7183 ◽  
Author(s):  
Dan Zhu ◽  
Denghu Chang ◽  
Lei Shi
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
One Pot ◽  
Metal Free ◽  
One Pot Synthesis ◽  
One Step ◽  
The One

A novel transition-metal-free method for the one-step synthesis of thiocyanates via the C–S bond cleavage of readily available thioethers was developed.

Potassium tert-Butoxide Mediated Reductive C–P Cross-Coupling of Arylvinyl Sulfides through C–S Bond Cleavage

Synlett ◽  
2020 ◽  
Author(s):  
Qingle Zeng ◽  
Jie Feng ◽  
Qiaoling Zhang ◽  
Fuhai Li ◽  
Lu Yang ◽  
...  
Keyword(s):  
Double Bond ◽  
Transition Metal ◽  
Bond Cleavage ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Phosphine Oxides ◽  
One Pot ◽  
Metal Free ◽  
Cross Coupling Reaction

AbstractA transition-metal-free t-BuOK-mediated reductive C–P cross-coupling reaction of arylvinyl sulfides with diarylphosphine oxides through C–S bond cleavage has been developed. This protocol not only permits the synthesis of diaryl(2-arylethyl)phosphine oxides, but also achieves an unprecedented construction of a C–P bond through C–S bond cleavage and reduction of a C–C double bond in one pot.

Metal-free, one-pot synthesis of 2-styrylquinolines via Friedländer annulation and sp3 C-H activation using 1,3-dimethylurea and L-tartaric acid (3:1) as deep eutectic solvent†

2022 ◽  
Author(s):  
Neeli Satyanarayana ◽  
Kota Sathish ◽  
Sakkani Nagaraju ◽  
Ravinder Pawar ◽  
Mohammad Faizan ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Deep Eutectic Solvent ◽  
Simple Metal ◽  
One Pot ◽  
Metal Free ◽  
One Pot Synthesis ◽  
Dimethyl Urea ◽  
The One

A simple, metal-free protocol is reported for the one-pot synthesis of 2-styrylquinolines using a combination of 1,3-dimethyl urea (1,3-DMU) and L-tartaric acid (LTA) (in 3:1 ratio) as deep eutectic solvent...

scholarly journals Metal-Free Photoredox-Catalyzed C–H/C–H Coupling of Arenes Enabled by Interrupted Pummerer Activation

2019 ◽  
Author(s):  
Miles Aukland ◽  
Mindaugas Šiaučiulis ◽  
Adam West ◽  
Gregory Perry ◽  
David Procter
Keyword(s):  
Natural Product ◽  
Selective Reduction ◽  
Cross Coupling ◽  
One Pot ◽  
Complex Molecules ◽  
Pummerer Reaction ◽  
Metal Free ◽  
Bond Forming ◽  
Coupling Partner ◽  
Bioactive Natural Product

<p>Aryl–aryl cross-coupling constitutes one of the most widely used procedures for the synthesis of high-value materials, ranging from pharmaceuticals to organic electronics and conducting polymers. The assembly of (hetero)biaryl scaffolds generally requires multiple steps; coupling partners must be functionalized before the key bond-forming event is considered. Thus, the development of selective C–H arylation processes in arenes, that side-step the need for prefunctionalized partners, is crucial for streamlining the construction of these key architectures. Here we report an expedient, one-pot assembly of (hetero)biaryl motifs using photocatalysis and two non-prefunctionalized arene partners. The approach is underpinned by the activation of a C–H bond in an arene coupling partner using the interrupted Pummerer reaction. A unique pairing of the organic photoredox catalyst and the intermediate dibenzothiophenium salts enables highly selective reduction in the presence of sensitive functionalities. The utility of the metal-free, one-pot strategy is exemplified by the synthesis of a bioactive natural product and the modification of complex molecules of societal importance.</p>

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