Photochemical proton-coupled C-H activation: an example using aliphatic fluorination.
Selective functionalization of unactivated C-H bonds is an ongoing chemical challenge. C-H activation requires the transfer of H+and e-, so called proton-coupled electron transfer (PCET) reactions. Recent efforts in photochemical PCET involving C-H bonds show great promise for the synthesis of new compounds. One such example is photochemical C-H fluorination reactions. In many cases, the discrete PCET mechanisms are yet to be defined in a systematic way. Here, we investigated electron transfer (ET) and PCET reactions of electronically excited 1,2,4,5-tetracyanobenzene and anthraquinone with the components of typical fluorination reactions. Analysis using kinetic and thermodynamic models, and steady-state and time-resolved fluorescence data, suggest that C-H activation proceeds efficiently where electronically excited sensitizers accept H˙.
Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. j.warren@sfu.ca.
Mackenzie J
MJ
Field
Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. j.warren@sfu.ca.
Soumalya
S
Sinha
Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. j.warren@sfu.ca and Canadian Institute for Applied Research, CIFAR Azrieli Global Scholar and Bio-Inspired Solar Energy Programs, Toronto, ON M5G 1Z8, Canada.
Jeffrey J
http://orcid.org/0000-0002-1747-3029
JJ
Warren