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Radical Reactivity via Transient Carbon Dioxide Radical Anion (CO2 •−).

Record Type:	Electronic resources : Monograph/item
Title/Author:	Radical Reactivity via Transient Carbon Dioxide Radical Anion (CO2 •−)./
Author:	Hendy, Cecilia M.
Description:	1 online resource (249 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 84-12, Section: B.
Contained By:	Dissertations Abstracts International84-12B.
Subject:	Organic chemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30593300click for full text (PQDT)
ISBN:	9798379716394

Radical Reactivity via Transient Carbon Dioxide Radical Anion (CO2 •−).
Hendy, Cecilia M.

Radical Reactivity via Transient Carbon Dioxide Radical Anion (CO2 •−). - 1 online resource (249 pages)

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

Thesis (Ph.D.)--Emory University, 2023.

Includes bibliographical references

Single electron reduction is a straightforward pathway towards the formation of valuable radical intermediates from electron poor substrates. Visible-light photoredox catalysis has transpired at the forefront of single electron chemistry over the past decade owing to its exceedingly mild energetic requirements and its ability to promote unprecedented carbon-carbon and carbon- heteroatom bond formations. However, a variety of valuable radical precursors extend beyond the energetic limits of traditional photoredox catalysts. We have developed an alternative method towards single electron reduction that relies on the carbon dioxide radical anion (CO2•−) as a powerful single electron reductant (E°1/2= -2.21 V vs SCE). We generate CO2•− through a hydrogen atom transfer (HAT) between formate and a thiol HAT catalyst. In addition to reduction, we found CO2•− undergoes radical conjugate addition with electron deficient olefins that have more negative reductions potentials to form the corresponding carboxylated products. Following these initial discoveries detailed in chapter 2, we exploit the highly reducing nature of CO2•− towards a variety of reductive transformations that enable unique carbon-carbon bond formations. The CO2•− system enabled highly selective 5-exo radical cyclizations from bromopyridines which was demonstrated in conjunction with a method to selectively form the 6-endo product. The selectivity was controlled through the choice of HAT catalyst. Last, we report a method developed for the coupling of difluorobenzylic radicals with N,N-dialkylhydrazones to form unique β-difluorobenzylic hydrazines.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798379716394Subjects--Topical Terms:

523952
Organic chemistry.
Subjects--Index Terms:

Radical reactivityIndex Terms--Genre/Form:

542853
Electronic books.

Radical Reactivity via Transient Carbon Dioxide Radical Anion (CO2 •−).
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502 $a Thesis (Ph.D.)--Emory University, 2023.
504 $a Includes bibliographical references
520 $a Single electron reduction is a straightforward pathway towards the formation of valuable radical intermediates from electron poor substrates. Visible-light photoredox catalysis has transpired at the forefront of single electron chemistry over the past decade owing to its exceedingly mild energetic requirements and its ability to promote unprecedented carbon-carbon and carbon- heteroatom bond formations. However, a variety of valuable radical precursors extend beyond the energetic limits of traditional photoredox catalysts. We have developed an alternative method towards single electron reduction that relies on the carbon dioxide radical anion (CO2•−) as a powerful single electron reductant (E°1/2= -2.21 V vs SCE). We generate CO2•− through a hydrogen atom transfer (HAT) between formate and a thiol HAT catalyst. In addition to reduction, we found CO2•− undergoes radical conjugate addition with electron deficient olefins that have more negative reductions potentials to form the corresponding carboxylated products. Following these initial discoveries detailed in chapter 2, we exploit the highly reducing nature of CO2•− towards a variety of reductive transformations that enable unique carbon-carbon bond formations. The CO2•− system enabled highly selective 5-exo radical cyclizations from bromopyridines which was demonstrated in conjunction with a method to selectively form the 6-endo product. The selectivity was controlled through the choice of HAT catalyst. Last, we report a method developed for the coupling of difluorobenzylic radicals with N,N-dialkylhydrazones to form unique β-difluorobenzylic hydrazines.
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653 $a Methodology
653 $a Single electron reduction
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