Mechanistic Insights into Iron-Catalyzed C-H Bond Activation and C-C Coupling

Brewer, Samantha M.; Schwartz, Timothy M.; Mekhail, Magy A.; Turan, Lara S.; Prior, Timothy J.; Hubin, Timothy J.; Janesko, Benjamin G.; Green, Kayla N.

Abstract

Iron-catalyzed C-C coupling reactions of pyrrole provide a unique alternative to the traditional Pd-catalyzed counterpart. However, many details regarding the actual mechanism remain unknown. A series of macrocyclic iron(III) complexes were used to evaluate specifics related to the role of O2, radicals, and μ-oxodiiron-complex participation in the catalytic cycle. It was determined that the mononuclear tetra-azamacrocyclic complex is a true catalyst and not a stoichiometric reagent, while more than one equivalent of a sacrificial oxidant is needed. Furthermore, the reaction does not proceed through an organic radical pathway. μ-Oxodiiron complexes are not involved in the main catalytic pathway, and the dimers are, in fact, off-cycle species that decrease catalytic efficiency.

Citation

Brewer, S. M., Schwartz, T. M., Mekhail, M. A., Turan, L. S., Prior, T. J., Hubin, T. J., Janesko, B. G., & Green, K. N. (in press). Mechanistic Insights into Iron-Catalyzed C-H Bond Activation and C-C Coupling. Organometallics, https://doi.org/10.1021/acs.organomet.1c00211

• Journal Article Type: Article
• Acceptance Date: Jul 2, 2021
• Online Publication Date: Jul 20, 2021
• Deposit Date: Jul 22, 2021
• Publicly Available Date: Jul 21, 2022
• Journal: Organometallics
• Print ISSN: 0276-7333
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1021/acs.organomet.1c00211
• Keywords: Absorption; Ligands; Oligomers; Pyrroles; Oxygen
• Public URL: https://hull-repository.worktribe.com/output/3808910