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Updated: Jun 17, 2026
![[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
Toward safer processes for C-C biaryl bond construction: catalytic direct C-H arylation and tin-free radical coupling
Susana Hernández1, Isabel Moreno, Raul SanMartin
1Kimika Organikoa II Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, 644 P.K. 48080 Bilbao, Spain.
Abstract:
A series of pyrazolo[1,5-f]phenanthridine derivatives has been efficiently synthesized by a short, straightforward sequence. A tandem amine-exchange/heterocyclization of enaminones was successfully applied to the regioselective preparation of 1,5-diarylpyrazole intermediates with structure resemblance to relevant nonsteroidal anti-inflammatory drugs such as celecoxib or tepoxalin. The final key step, cyclization by intramolecular biaryl bond formation, was accomplished by two alternative methodologies: radical coupling and catalytic direct arylation via C-H activation. The scope and limitations of the two methodologies have been explored and their complementariness has been established. In addition, polymer-supported heterogeneous catalysts have been compared with homogeneous analogues. In the radical process, toxic tin derivatives have been avoided in order to employ environmentally safer protocols.
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