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Vitamin B12 Catalyzed Atom Transfer Radical Addition
Keith Ó Proinsias1, Agnieszka Jackowska1, Katarzyna Radzewicz1
1Institute of Organic Chemistry PAS , Kasprzaka 44/52, 01-224 Warsaw, Poland.
Organic Letters
|December 23, 2017
Summary
Vitamin B12 catalyzes atom transfer radical addition reactions with high selectivity. This natural cobalt complex facilitates organic halide addition to olefins, primarily avoiding polymerization except for acrylates.
Area of Science:
- Organic Chemistry
- Polymer Chemistry
- Organometallic Chemistry
Background:
- Vitamin B12 is a natural cobalt-containing cofactor.
- Atom transfer radical reactions are important in organic synthesis.
- Controlling selectivity in radical reactions is a key challenge.
Purpose of the Study:
- To investigate the catalytic activity of Vitamin B12 in atom transfer radical addition (ATRA).
- To determine the selectivity of Vitamin B12-catalyzed ATRA reactions.
- To explore the potential for Vitamin B12 to mediate atom transfer radical polymerization (ATRP).
Main Methods:
- Utilizing Vitamin B12 as a catalyst.
- Employing organic halides and olefins as substrates.
- Analyzing reaction products to assess selectivity.
Main Results:
- Vitamin B12 effectively catalyzes the ATRA of organic halides to olefins.
- The reaction conditions exhibit high selectivity for ATRA.
- Atom transfer radical polymerization (ATRP) was observed only with acrylate monomers.
Conclusions:
- Vitamin B12 is a viable catalyst for selective ATRA reactions.
- The catalytic system demonstrates excellent control, preventing unwanted polymerization.
- This finding opens avenues for using Vitamin B12 in controlled radical additions.
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