Persistent Polyhalogenated Compounds: Biochemistry, Toxicology, Medical Applications, and Associated Environmental Issues

Kirk, Kenneth L.

doi:10.1007/978-1-4684-5817-6_8

“…In contrast, the synthetically appealing, simultaneous transfer of two functional groups, in a catalytic reversible transfer difunctionalization process, has remained largely elusive, despite the vast synthetic potential of these reactions in organic synthesis. In particular, reactions involving the formal transfer of extremely reactive and corrosive molecules, such as Cl2 (17,18) or Br2, from easier-tohandle, stable bulk chemicals, such as inexpensive 1,2-dichloro-and 1,2-dibromoethane, would be highly desirable because of the widespread synthetic applications of dihalogenated molecules in flame retardants, pesticides, materials and natural products (1,2,19) (Fig. 1A).…”

Section: Main Textmentioning

confidence: 99%

“…V icinal dibromides and dichlorides have found widespread applications as flame retardants, pest control agents, polymers, and pharmaceuticals (1,2). They also serve as versatile synthetic intermediates in organic chemistry because of the inherent reactivity of carbon-halogen bonds (3,4).…”

mentioning

confidence: 99%

Merging shuttle reactions and paired electrolysis for reversible vicinal dihalogenations

Dong

¹

,

Roeckl

²

,

Waldvogel

³

et al. 2021

Science

View full text Add to dashboard Cite

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.

show abstract

“…In contrast, the synthetically appealing, simultaneous transfer of two functional groups, in a catalytic reversible transfer difunctionalization process, has so far remained elusive, despite the vast synthetic potential of these reactions in organic synthesis. In particular, reactions involving the formal transfer of extremely hazardous molecules, such as Cl2 15,16 or Br2, from easy-to-handle and less toxic bulk chemicals, such as inexpensive 1,2-dichloro-and 1,2-dibromoethane, would be highly desirable because of the widespread synthetic applications of polyhalogenated molecules in flame retardants, pesticides, materials and natural products 1,2,17 (Fig. 1A).…”

Section: Main Textmentioning

confidence: 99%

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

Dong¹,

Röckl²,

Waldvogel³

et al. 2020

Preprint

View full text Add to dashboard Cite

<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>

show abstract

“…In contrast, the synthetically appealing, simultaneous transfer of two functional groups, in a catalytic reversible transfer difunctionalization process, has so far remained elusive, despite the vast synthetic potential of these reactions in organic synthesis. In particular, reactions involving the formal transfer of extremely hazardous molecules, such as Cl2 15,16 or Br2, from easy-to-handle and less toxic bulk chemicals, such as inexpensive 1,2-dichloro-and 1,2-dibromoethane, would be highly desirable because of the widespread synthetic applications of polyhalogenated molecules in flame retardants, pesticides, materials and natural products 1,2,17 (Fig. 1A).…”

Section: Main Textmentioning

confidence: 99%

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

Dong¹,

Röckl²,

Waldvogel³

et al. 2020

Preprint

View full text Add to dashboard Cite

<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>

show abstract

Persistent Polyhalogenated Compounds: Biochemistry, Toxicology, Medical Applications, and Associated Environmental Issues

Cited by 6 publications

References 66 publications

Merging shuttle reactions and paired electrolysis for reversible vicinal dihalogenations

Merging shuttle reactions and paired electrolysis for reversible vicinal dihalogenations

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

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

Contact Info

Product

Resources

About