Utilising Sodium‐Mediated Ferration for Regioselective Functionalisation of Fluoroarenes via C−H and C−F Bond Activations

• Published in: Angewandte Chemie International Edition Vol. 57; no. 1; pp. 187 - 191
• Main Authors: Maddock, Lewis C. H., Nixon, Tracy, Kennedy, Alan R., Probert, Michael R., Clegg, William, Hevia, Eva
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 02-01-2018
• Edition: International ed. in English
• Subjects: alkali metals; C−F bond activation; Hydrogen bonds; Intermediates; Iron; metalation; mixed-metal chemistry; Regioselectivity; Sodium; Substrates; Switches; C−F bond activation; iron; metalation; mixed-metal chemistry; alkali metals
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201709750

Pairing iron bis(amide) Fe(HMDS)2 with Na(HMDS) to form new sodium ferrate base [(dioxane)0.5⋅NaFe(HMDS)3] (1) enables regioselective mono and di‐ferration (via direct Fe−H exchange) of a wide range of fluoroaromatic substrates under mild reaction conditions. Trapping of several ferrated intermediates has provided key insight into how synchronised Na/Fe cooperation operates in these transformations. Furthermore, using excess 1 at 80 °C switches on a remarkable cascade process inducing the collective twofold C−H/threefold C−F bond activations, where each C−H bond is transformed to a C−Fe bond whereas each C−F bond is transformed into a C−N bond.
High five! Exploiting bimetallic cooperation, sodium tris(amido) ferrate 1 induces the collective cleavage of five (three C−F and two C−H) bonds of trifluoroarene substrates via a cascade activation process.