Direct Observation of a Nonheme Iron(IV)–Oxo Complex That Mediates Aromatic C–F Hydroxylation

Sumit Sahu †, Matthew G. Quesne ‡, Casey G. Davies §, Maximilian Dürr ∥, Ivana Ivanović-Burmazović ∥, Maxime A. Siegler †, Guy N. L. Jameson *§, Sam P. de Visser *‡, and David P.Goldberg *†

† Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States

‡ Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom

§ Department of Chemistry & MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand

∥ Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, 91058 Erlangen, Germany

J. Am. Chem. Soc., Article ASAP

DOI: 10.1021/ja507346t

Publication Date (Web): September 23, 2014

Copyright © 2014 American Chemical Society

dpg@jhu.edu, gjameson@chemistry.otago.ac.nz, sam.devisser@manchester.ac.uk

Section:

Physical Organic Chemistry

Abstract

The synthesis of a pentadentate ligand with strategically designed fluorinated arene groups in the second coordination sphere of a nonheme iron center is reported. The oxidatively resistant fluorine substituents allow for the trapping and characterization of an FeIV(O) complex at −20 °C. Upon warming of the FeIV(O) complex, an unprecedented arene C–F hydroxylation reaction occurs. Computational studies support the finding that substrate orientation is a critical factor in the observed reactivity. This work not only gives rare direct evidence for the participation of an FeIV(O) species in arene hydroxylation but also provides the first example of a high-valent iron–oxo complex that mediates aromatic C–F hydroxylation.