scholarly journals Merging Shuttle Reactions and Paired Electrolysis: E-Shuttle Unlocks Reversible Halogenations

2020 ◽  
Author(s):  
Xichang Dong ◽  
Johannes L. Röckl ◽  
Siegfried R. Waldvogel ◽  
Bill Morandi
Keyword(s):  
Organic Chemistry ◽  
Flame Retardants ◽  
Environmental Pollutant ◽  
Halogen Bonds ◽  
Recycling Process ◽  
New Horizons ◽  
Synthetic Intermediates ◽  
Halogenated Pollutants ◽  
Hazardous Compounds ◽  
Different Soils

<p>Polyhalogenated molecules have found widespread applications as flame retardants, pest-control agents, polymers and pharmaceuticals. They also serve as versatile synthetic intermediates in organic chemistry due to the inherent reactivity of carbon-halogen bonds. Despite these attractive features, the preparation of polyhalogenated molecules still mainly relies on the use of highly toxic and corrosive halogenating reagents, such as Cl<sub>2</sub> and Br<sub>2</sub>, which are hazardous compounds to transport, store, and handle. Moreover, the use of such highly reactive reagents inherently makes the development of the reverse reactions, <i>retro</i>-dihalogenations, highly challenging, despite their potential for the recycling of persistent halogenated pollutants. Here, we introduce an electrochemically-assisted shuttle<i> (e-shuttle)</i> paradigm for the facile and scalable interconversion of alkenes and vicinal dihalides, a class of reactions which can be used both to synthesize useful polyhalogenated molecules from simple alkenes and to recycle waste material through <i>retro</i>-dihalogenation. The power of this reaction is best highlighted by an example, in which different soils contaminated with a persistent environmental pollutant (Lindane), could be directly used as Cl<sub>2</sub>-donors for the transfer dichlorination of simple feedstock alkenes, merging a recycling process with a synthetically relevant dichlorination reaction. We further demonstrate that this paired electrolysis-enabled shuttle protocol, which uses a simple setup and inexpensive electrodes, is applicable to four different, synthetically useful transfer halogenation reactions, and can be readily scaled-up to a decagram scale. In a broader context, the symbiotic merging of shuttle reactions and electrochemistry introduced in this work opens new horizons for safer transfer functionalization reactions that will address important challenges across the molecular sciences.</p> <div><br><div> </div> </div>

scholarly journals Merging Shuttle Reactions and Paired Electrolysis: E-Shuttle Unlocks Reversible Halogenations

2020 ◽  
Author(s):  
Xichang Dong ◽  
Johannes L. Röckl ◽  
Siegfried R. Waldvogel ◽  
Bill Morandi
Keyword(s):  
Organic Chemistry ◽  
Flame Retardants ◽  
Environmental Pollutant ◽  
Halogen Bonds ◽  
Recycling Process ◽  
New Horizons ◽  
Synthetic Intermediates ◽  
Halogenated Pollutants ◽  
Hazardous Compounds ◽  
Different Soils

<p>Polyhalogenated molecules have found widespread applications as flame retardants, pest-control agents, polymers and pharmaceuticals. They also serve as versatile synthetic intermediates in organic chemistry due to the inherent reactivity of carbon-halogen bonds. Despite these attractive features, the preparation of polyhalogenated molecules still mainly relies on the use of highly toxic and corrosive halogenating reagents, such as Cl<sub>2</sub> and Br<sub>2</sub>, which are hazardous compounds to transport, store, and handle. Moreover, the use of such highly reactive reagents inherently makes the development of the reverse reactions, <i>retro</i>-dihalogenations, highly challenging, despite their potential for the recycling of persistent halogenated pollutants. Here, we introduce an electrochemically-assisted shuttle<i> (e-shuttle)</i> paradigm for the facile and scalable interconversion of alkenes and vicinal dihalides, a class of reactions which can be used both to synthesize useful polyhalogenated molecules from simple alkenes and to recycle waste material through <i>retro</i>-dihalogenation. The power of this reaction is best highlighted by an example, in which different soils contaminated with a persistent environmental pollutant (Lindane), could be directly used as Cl<sub>2</sub>-donors for the transfer dichlorination of simple feedstock alkenes, merging a recycling process with a synthetically relevant dichlorination reaction. We further demonstrate that this paired electrolysis-enabled shuttle protocol, which uses a simple setup and inexpensive electrodes, is applicable to four different, synthetically useful transfer halogenation reactions, and can be readily scaled-up to a decagram scale. In a broader context, the symbiotic merging of shuttle reactions and electrochemistry introduced in this work opens new horizons for safer transfer functionalization reactions that will address important challenges across the molecular sciences.</p> <div><br><div> </div> </div>

scholarly journals Merging Shuttle Reactions and Paired Electrolysis: E-Shuttle Unlocks Reversible Halogenations

2020 ◽  
Author(s):  
Xichang Dong ◽  
Johannes L. Röckl ◽  
Siegfried R. Waldvogel ◽  
Bill Morandi
Keyword(s):  
Organic Chemistry ◽  
Flame Retardants ◽  
Environmental Pollutant ◽  
Halogen Bonds ◽  
Recycling Process ◽  
New Horizons ◽  
Synthetic Intermediates ◽  
Halogenated Pollutants ◽  
Hazardous Compounds ◽  
Different Soils

<p>Polyhalogenated molecules have found widespread applications as flame retardants, pest-control agents, polymers and pharmaceuticals. They also serve as versatile synthetic intermediates in organic chemistry due to the inherent reactivity of carbon-halogen bonds. Despite these attractive features, the preparation of polyhalogenated molecules still mainly relies on the use of highly toxic and corrosive halogenating reagents, such as Cl<sub>2</sub> and Br<sub>2</sub>, which are hazardous compounds to transport, store, and handle. Moreover, the use of such highly reactive reagents inherently makes the development of the reverse reactions, <i>retro</i>-dihalogenations, highly challenging, despite their potential for the recycling of persistent halogenated pollutants. Here, we introduce an electrochemically-assisted shuttle<i> (e-shuttle)</i> paradigm for the facile and scalable interconversion of alkenes and vicinal dihalides, a class of reactions which can be used both to synthesize useful polyhalogenated molecules from simple alkenes and to recycle waste material through <i>retro</i>-dihalogenation. The power of this reaction is best highlighted by an example, in which different soils contaminated with a persistent environmental pollutant (Lindane), could be directly used as Cl<sub>2</sub>-donors for the transfer dichlorination of simple feedstock alkenes, merging a recycling process with a synthetically relevant dichlorination reaction. We further demonstrate that this paired electrolysis-enabled shuttle protocol, which uses a simple setup and inexpensive electrodes, is applicable to four different, synthetically useful transfer halogenation reactions, and can be readily scaled-up to a decagram scale. In a broader context, the symbiotic merging of shuttle reactions and electrochemistry introduced in this work opens new horizons for safer transfer functionalization reactions that will address important challenges across the molecular sciences.</p> <div><br><div> </div> </div>

scholarly journals Halogen bonds of halonium ions

2020 ◽  
Vol 49 (9) ◽  
pp. 2688-2700 ◽  
Author(s):  
Lotta Turunen ◽  
Máté Erdélyi
Keyword(s):  
Organic Chemistry ◽  
Halogen Bond ◽  
Halogen Bonds ◽  
Synthetic Organic Chemistry

Halonium ions are particularly strong halogen bond donors, and are accordingly valuable tools for a variety of fields, such as supramolecular and synthetic organic chemistry.

scholarly journals Emerging and Legacy Organic Halogenated Pollutants in Indoor Dusts

Proceedings ◽  
2019 ◽  
Vol 44 (1) ◽  
pp. 3
Author(s):  
Giulia Simonetti ◽  
Elisa Sonego ◽  
Federica Castellani ◽  
Patrizia Di Filippo ◽  
Carmela Riccardi ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Polybrominated Diphenyl Ethers ◽  
Flame Retardants ◽  
Cost Effective ◽  
Contamination Level ◽  
Indoor Environments ◽  
Dust Collection ◽  
Settled Dust ◽  
Halogenated Pollutants ◽  
Emerging Organic Pollutants

In indoor environments, the concentration of halogenated organic pollutants in dust can be high due to the presence of products treated with these chemicals. In this study, we monitored emerging organic pollutants, such as novel brominated flame retardants (nBFRs) and some perfluoroalkyl substances (PFAS), together with legacy polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDEs) in settled dust collected in five different (domestic and occupational) environments. In workplaces, a high incidence of PCBs, PBDEs and nBFRs occurred. Dust collection represents a simple, fast and cost-effective sampling and dust contamination level can be a useful indicator of environment healthiness.

Recent Trends in Group 9–Catalyzed C−H Borylation Reactions: Different Strategies to Control Site-, Regio-, and Stereoselectivity

Synthesis ◽  
2021 ◽  
Author(s):  
Lukas Veth ◽  
Hanusch Grab ◽  
Pawel Dydio
Keyword(s):  
Organic Chemistry ◽  
Transition Metal ◽  
Medicinal Chemistry ◽  
Organic Molecules ◽  
Recent Literature ◽  
Control Site ◽  
High Abundance ◽  
Future Potential ◽  
Recent Trends ◽  
Synthetic Intermediates

Organoboron compounds continue contributing substantially to advances in organic chemistry with their increasing role as both synthetic intermediates and target compounds for medicinal chemistry. Particularly attractive methods of their synthesis are based on the direct borylation of C−H bonds of available starting materials since no additional pre-functionalization steps are required. However, due to the high abundance of C−H bonds with similar reactivity in organic molecules, synthetically useful C−H borylation protocols demand sophisticated strategies to achieve high regio- and stereoselectivity. For this purpose, selective transition-metal-based catalysts have been developed, with group 9-centered catalysts being among the most commonly utilized. Recently, a multitude of diverse strategies has been developed to push the boundaries of C−H borylation reactions with respect to their regio- and enantioselectivity. Herein, we provide an overview of approaches for the C−H borylation of arenes, alkenes, and alkanes based on group 9-centered catalysts with a focus on the recent literature. Lastly, an outlook is given to assess the future potential of the field.

scholarly journals Merging shuttle reactions and paired electrolysis for reversible vicinal dihalogenations

Science ◽  
2021 ◽  
Vol 371 (6528) ◽  
pp. 507-514
Author(s):  
Xichang Dong ◽  
Johannes L. Roeckl ◽  
Siegfried R. Waldvogel ◽  
Bill Morandi
Keyword(s):  
Soil Samples ◽  
Waste Material ◽  
Environmental Persistence ◽  
Graphite Electrodes ◽  
Elemental Chlorine ◽  
Modern Chemistry ◽  
Wide Range ◽  
Commodity Chemicals ◽  
Synthetic Intermediates ◽  
Halogenated Pollutants

Vicinal dibromides and dichlorides are important commodity chemicals and indispensable synthetic intermediates in modern chemistry that are traditionally synthesized using hazardous elemental chlorine and bromine. Meanwhile, the environmental persistence of halogenated pollutants necessitates improved approaches to accelerate their remediation. Here, we introduce an electrochemically assisted shuttle (e-shuttle) paradigm for the facile and scalable interconversion of alkenes and vicinal dihalides, a class of reactions that can be used both to synthesize useful dihalogenated molecules from simple alkenes and to recycle waste material through retro-dihalogenation. The reaction is demonstrated using 1,2-dibromoethane, as well as 1,1,1,2-tetrachloroethane or 1,2-dichloroethane, to dibrominate or dichlorinate, respectively, a wide range of alkenes in a simple setup with inexpensive graphite electrodes. Conversely, the hexachlorinated persistent pollutant lindane could be fully dechlorinated to benzene in soil samples using simple alkene acceptors.

scholarly journals Sterically Controlled Late-Stage C–H Alkynylation of Arenes

2019 ◽  
Author(s):  
Arup Mondal ◽  
Hao Chen ◽  
Lea Flämig ◽  
Philipp Wedi ◽  
Manuel van Gemmeren
Keyword(s):  
Organic Chemistry ◽  
Late Stage ◽  
Functional Materials ◽  
Bioactive Molecules ◽  
Sonogashira Coupling ◽  
Traditional Methods ◽  
Complementary Product ◽  
Complementary Approach ◽  
Synthetic Intermediates ◽  
Directing Group

Phenylacetylenes are key structural motifs in organic chemistry, which find widespread applications in bioactive molecules, synthetic intermediates, functional materials and reagents. These molecules are typically prepared from pre-functionalized starting materials, e.g. using the Sonogashira coupling, or using directing group-based C–H activation strategies. While highly efficient, these approaches remain limited by their inherent selectivities for specific regioisomers. Herein we present a complementary approach based on an arene-limited nondirected C–H activation. The reaction is predominantly controlled by steric rather than electronic factors and thereby gives access to a complementary product spectrum with respect to traditional methods. A broad scope as well as the suitability of this protocol for late-stage functionalization are demonstrated.<br>

scholarly journals Sterically Controlled Late-Stage C–H Alkynylation of Arenes

2019 ◽  
Author(s):  
Arup Mondal ◽  
Hao Chen ◽  
Lea Flämig ◽  
Philipp Wedi ◽  
Manuel van Gemmeren
Keyword(s):  
Organic Chemistry ◽  
Late Stage ◽  
Functional Materials ◽  
Bioactive Molecules ◽  
Sonogashira Coupling ◽  
Traditional Methods ◽  
Complementary Product ◽  
Complementary Approach ◽  
Synthetic Intermediates ◽  
Directing Group

Phenylacetylenes are key structural motifs in organic chemistry, which find widespread applications in bioactive molecules, synthetic intermediates, functional materials and reagents. These molecules are typically prepared from pre-functionalized starting materials, e.g. using the Sonogashira coupling, or using directing group-based C–H activation strategies. While highly efficient, these approaches remain limited by their inherent selectivities for specific regioisomers. Herein we present a complementary approach based on an arene-limited nondirected C–H activation. The reaction is predominantly controlled by steric rather than electronic factors and thereby gives access to a complementary product spectrum with respect to traditional methods. A broad scope as well as the suitability of this protocol for late-stage functionalization are demonstrated.<br>

Highly Selective Hydroiodination of Carbon-Carbon Double or Triple Bonds

2020 ◽  
Vol 24 (18) ◽  
pp. 2153-2168
Author(s):  
Yuki Yamamoto ◽  
Shin-ichi Kawaguchi ◽  
Shintaro Kodama ◽  
Akihiro Nomoto ◽  
Akiya Ogawa
Keyword(s):  
Organic Chemistry ◽  
Organic Synthesis ◽  
Building Blocks ◽  
Review Article ◽  
Multiple Bonds ◽  
Triple Bonds ◽  
Synthetic Intermediates ◽  
Characteristic Features

Iodine is an element that exhibits characteristic features of heavy halogen, and several compounds containing iodine constitute important synthetic intermediates due to synthetically easy manipulation. To utilize iodine units for organic synthesis, a highly regio- and stereoselective introduction of iodine to versatile building blocks is significant, and a lot of research works for the selective introduction of iodine to alkynes or alkenes have been conducted. In this review article, we describe regio- and stereoselective hydroiodination to multiple bonds of building blocks, and its synthetic applications as key intermediates to construct several important compounds in organic chemistry.

scholarly journals PAH and POP Presence in Plastic Waste and Recyclates: State of the Art

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3451
Author(s):  
Juan A. Conesa ◽  
Samuel S. Nuñez ◽  
Núria Ortuño ◽  
Julia Moltó
Keyword(s):  
Aromatic Hydrocarbons ◽  
Circular Economy ◽  
Life Cycle Analysis ◽  
Flame Retardants ◽  
State Of The Art ◽  
Recycling Process ◽  
Great Saving ◽  
Dioxins And Furans ◽  
Polycyclic Aromatic ◽  
Recycled Plastics

The presence of different pollutants in recycled plastics is reviewed in this article. The desirable circular economy of plastics should be linked to the availability of clean recycled plastics with a non-significant and small to nil amount of substances of concern. Different researchers found polycyclic aromatic hydrocarbons (PAHs) and Persistent Organic Pollutants (POPs), such as brominated flame retardants (BFRs), pesticides, dioxins and furans (PCDD/Fs and PBDD/Fs) in plastic recyclates. This represents an added difficulty to the effective recycling process of plastics that reduces the demand for energy and materials, in addition to posing a great environmental danger since they represent a vector of accumulation of the contaminants that will finally appear in the most unexpected products. Life Cycle Analysis of the plastic wastes recycling process indicates a great saving of energy, water and CO2 emissions.

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