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06:49
Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst
Published on: April 22, 2016
Atom-transfer cyclization with CuSO4/KBH4: a formal "activators generated by electron transfer" process also
Andrew J Clark1, Alana E C Collis, David J Fox
1Department of Chemistry, University of Warwick, Coventry, West Midlands CV4 7AL, UK. a.j.clark@warwick.ac.uk
The Journal of Organic Chemistry
|August 7, 2012
Summary
This study introduces a novel copper-catalyzed atom-transfer radical cyclization method using minimal catalyst loading. The efficient process works at room temperature in air, offering a greener alternative for synthesizing complex molecules.
Area of Science:
- Organic Chemistry
- Catalysis
- Polymer Science
Background:
- Atom-transfer radical cyclization (ATRC) is crucial for synthesizing cyclic compounds.
- Traditional ATRC often requires high catalyst concentrations and specific conditions.
- Developing efficient and environmentally friendly ATRC methods is an ongoing challenge.
Purpose of the Study:
- To develop a highly efficient ATRC protocol using low catalyst loading.
- To explore the use of a stable copper source (CuSO(4)·5H(2)O) in ATRC.
- To demonstrate the applicability of the method in controlled radical polymerization.
Main Methods:
- Utilized copper(II) sulfate pentahydrate (CuSO(4)·5H(2)O) as a catalyst precursor.
- Employed borohydride salts as reducing agents in an activators generated by electron transfer (AGET) system.
- Conducted reactions at room temperature in air using environmentally benign solvents like ethanol.
- Investigated cyclization onto alkynes and controlled radical polymerization of styrene.
Main Results:
- Achieved efficient 4-exo and 5-exo-trig cyclizations with as little as 0.05 mol % catalyst.
- Demonstrated tunable product distribution in radical-polar crossover reactions by adjusting borohydride amounts.
- Successfully performed cyclizations onto alkynes within 20 minutes.
- Showcased controlled radical polymerization of styrene with enhanced rates compared to conventional atom-transfer radical polymerization (ATRP).
Conclusions:
- The developed AGET ATRC protocol is highly efficient, requiring minimal catalyst loading.
- The method offers a greener and more accessible approach to radical cyclizations and polymerizations.
- This versatile copper-catalyzed system provides a valuable tool for synthetic chemists and polymer scientists.
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