scholarly journals Straightforward Strategies for the Preparation of NH-Sulfox­imines: A Serendipitous Story

Synlett ◽  
2017 ◽  
Vol 28 (19) ◽  
pp. 2525-2538 ◽  
Author(s):  
James Bull ◽  
Renzo Luisi ◽  
Leonardo Degennaro
Keyword(s):  
Transition Metal ◽  
Physicochemical Properties ◽  
Direct Synthesis ◽  
Transition Metal Catalysts ◽  
Hypervalent Iodine ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Recent Developments ◽  
New Procedures

Sulfoximines are emerging as valuable new isosteres for use in medicinal chemistry, with the potential to modulate physicochemical properties. Recent developments in synthetic strategies have made the unprotected ‘free’ NH-sulfoximine group more readily available, facilitating further study. This account reviews approaches to NH-sulfoximines, with a focus on our contribution to the field. Starting from the development of catalytic strategies involving transition metals, more sustainable metal-free processes have been discovered. In particular, the use of hypervalent iodine reagents to mediate NH-transfer to sulfoxides is described, along with an assessment of the substrate scope. Furthermore, a one-pot strategy to convert sulfides directly into NH-sulfoximines is discussed, with N- and O-transfer occurring under the reaction conditions. Mechanistic evidence for the new procedures is included as well as relevant synthetic applications that further exemplify the potential of these approaches.1 Introduction2 Strategies to Form NH-Sulfoximines Involving Transition-Metal Catalysts3 Metal-Free Strategies to Prepare NH-Sulfoximines4 Mechanistic Evidence for the Direct Synthesis of NH-Sulfoximines from Sulfoxides and Sulfides5 Further Applications6 Conclusion

Transition-Metal-Free Catalysis for the Reductive ­Functionalization of CO2 with Amines

Synlett ◽  
2018 ◽  
Vol 29 (05) ◽  
pp. 548-555 ◽  
Author(s):  
Liang-Nian He ◽  
Xiao-Fang Liu ◽  
Xiao-Ya Li ◽  
Chang Qiao
Keyword(s):  
Transition Metal ◽  
Energy Content ◽  
Bond Formation ◽  
Energy Storage Materials ◽  
One Pot ◽  
Metal Free ◽  
Recent Developments ◽  
Electron Reduction ◽  
Reduction Of Co2 ◽  
Hierarchical Reduction

Reductive functionalization of CO2 with amines and a reductant, which combines both reduction of CO2 and C–N bond formation in one pot to produce versatile chemicals and energy-storage materials such as formamides, aminals, and methylamines that are usually derived from petroleum feedstock, would be appealing and promising. Herein, we give a brief review on recent developments in the titled CO2 chemistry by employing transition-metal-free catalysis, which can be catalogued as below according to the diversified energy content of the products, that is formamides, aminals, and methylamines being consistent with 2-, 4-, and 6-electron reduction of CO2, respectively. Notably, hierarchical reduction of CO2 with amines to afford at least two products, for example, formamides and methylamines, could be realized with the same catalyst through tuning the hydrosilane type, reaction temperature, or CO2 pressure. Finally, the opportunities and challenges of the reductive functionalization of CO2 with amines are also highlighted.1 Introduction2 2-Electron Reduction of CO2 to Formamide3 6-Electron Reduction of CO2 to Methylamine4 4-Electron Reduction of CO2 to Aminal5 Hierarchical Reduction of CO2 with Amines6 Conclusion

Aryne insertion into the PO bond: one-pot synthesis of quaternary phosphonium triflates

2019 ◽  
Vol 17 (26) ◽  
pp. 6450-6460 ◽  
Author(s):  
Kashmiri Neog ◽  
Dhiraj Dutta ◽  
Babulal Das ◽  
Pranjal Gogoi
Keyword(s):  
Transition Metal ◽  
Phosphine Oxide ◽  
Direct Synthesis ◽  
One Pot ◽  
Metal Free ◽  
One Pot Synthesis ◽  
Synthetic Strategy

A novel transition-metal free synthetic strategy for the direct synthesis of quaternary phosphonium triflates via insertion of aryne into phosphine oxide.

Base-mediated intramolecular one-pot double-cyclization of epoxide-tethered 2-fluorobenzenesulfonamides: an avenue to 1,4-benzoxazine-fused benzothiaoxazepine-1,1-dioxides

2020 ◽  
Vol 18 (2) ◽  
pp. 220-224 ◽  
Author(s):  
Jonali Das ◽  
Biraj Jyoti Borah ◽  
Sajal Kumar Das
Keyword(s):  
Transition Metal ◽  
Diastereoselective Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free

A regio- and diastereoselective synthesis of pharmaceutically relevant 1,4-benzoxazine-fused benzothiaoxazepine-1,1-dioxides has been achieved under transition metal-free mild reaction conditions.

Heterogeneous catalysis for the direct synthesis of chemicals by borrowing hydrogen methodology

2015 ◽  
Vol 5 (3) ◽  
pp. 1412-1427 ◽  
Author(s):  
Ken-ichi Shimizu
Keyword(s):  
Heterogeneous Catalysis ◽  
Transition Metal ◽  
Hydrogen Transfer ◽  
Direct Synthesis ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
One Pot ◽  
One Pot Synthesis ◽  
Borrowing Hydrogen ◽  
The One

This review summarizes the recent examples of hydrogen transfer-type reactions using supported transition metal catalysts with special emphasis on the one-pot synthesis of chemicals by borrowing hydrogen methodology.

scholarly journals One Pot and Metal-Free Approach to 3-(2-Hydroxybenzoyl)-1-aza-anthraquinones

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 3017
Author(s):  
Jiaqi Yuan ◽  
Qian He ◽  
Shanshan Song ◽  
Xiaofei Zhang ◽  
Zehong Miao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Functional Group ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Inert Gas ◽  
One Pot ◽  
Metal Free ◽  
Mild Conditions ◽  
Anthraquinone Derivatives

Herein, a direct strategy to synthesize 3-(2-hydroxybenzoyl)-1-aza-anthraquinones with excellent efficiency, mild conditions, and benign functional group compatibility was reported. A variety of 3-formylchromone compounds were employed as compatible substrates and this protocol gave the 3-(2-hydroxybenzoyl)-1-aza-anthraquinone derivatives in good to excellent yields without inert gas and expensive transition metal catalysts. Some compounds displayed good anti-proliferative activities.

scholarly journals Electrochemical Umpolung of Bromide: Transition-Metal-Free Bromination of Indole C–H Bond

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 696 ◽  
Author(s):  
Pan Zhang ◽  
Jianbin Chen ◽  
Wei Gao ◽  
Yiting Xiao ◽  
Changwei Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electrode Material ◽  
Environmentally Friendly ◽  
Transition Metal Catalysts ◽  
Reaction Conditions ◽  
Metal Free ◽  
Chemical Oxidants ◽  
Bromide Ion ◽  
Environmentally Friendly Approach ◽  
Graphite Rod

A facile and sustainable electrochemical umpolung of bromide ion protocol was developed under mild reaction conditions. Transition metal catalysts and exogenous chemical oxidants were obviated for the bromination of C–H bond. Notably, graphite rod, which is commercially available at supermarkets and is inexpensive, was employed as the electrode material. This operationally easy and environmentally friendly approach accomplished the synthesis of 3-bromoindole in excellent yield and regioselectivity.

Direct Synthesis of Nitrones via Transition-Metal-Free Ring-Opening of N-Tosylaziridines with the Nitrogen Atom of Various (E)-Aldoximes and (E)-Ketoximes

Synthesis ◽  
2019 ◽  
Vol 51 (21) ◽  
pp. 4043-4057
Author(s):  
Xing Li ◽  
Wenjing Yan ◽  
Rui Zhang ◽  
Honghong Chang ◽  
Wenchao Gao ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Transition Metal ◽  
Oxygen Atom ◽  
Ring Opening ◽  
Direct Synthesis ◽  
Reaction Conditions ◽  
Free Ring ◽  
Metal Free ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions

The KOH-, K2CO3-, or Et3N-catalyzed ring-opening reaction of N-tosylaziridines using the nitrogen atom of a series of (E)-aldoximes and (E)-ketoximes as a nucleophilic atom instead of an oxygen atom was developed to construct various nitrones under mild reaction conditions. Diverse (E)-aldoximes and (E)-ketoximes were demonstrated to be compatible with this reaction and the products of O-ring-opening reactions were not detected for most examples.

Regioselective C3-H Trifluoromethylation of 2H-Indazole Under Transition-Metal-Free Photoredox Catalysis

2019 ◽  
Author(s):  
Arumugavel Murugan ◽  
Venkata Nagarjuna Babu ◽  
Nagaraj Sabarinathan ◽  
Sharada Duddu. S
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Practical Approach ◽  
Hypervalent Iodine ◽  
Radical Mechanism ◽  
Photoredox Catalysis ◽  
Metal Free

Here we report a visible-light-promoted metal-free regioselective C3-H trifluoromehtylation reaction that proceeds via radical mechanism and which supported by control experiments. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the present trifluoromethylation reaction and synthesis of a library of trifluoromethylated indazoles.

Synthesis of Pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by Alkyne-Carbonyl Metathesis

Synthesis ◽  
2020 ◽  
Author(s):  
Peter Ehlers ◽  
Peter Langer ◽  
Marian Blanco Ponce ◽  
Silvio Parpart ◽  
Alexander Villinger ◽  
...  
Keyword(s):  
Heterocyclic Compounds ◽  
Metathesis Reaction ◽  
Synthetic Methodology ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Modular Synthesis

AbstractA concise and modular synthesis of pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by a one-pot two-step reaction consisting of electrophilic acylation followed by an alkyne-carbonyl-metathesis reaction as the final cyclization step is reported. This developed synthetic methodology allows the facile synthesis of these heterocyclic core structures in mainly high overall yields under metal-free conditions. Reaction conditions are carefully optimized and display a novel supplement to access these tricyclic heterocyclic compounds.

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