Cu(OTf)₂-Mediated Fluorination of Aryltrifluoroborates with Potassium Fluoride

Abstract

This Communication describes the Cu(OTf)2-mediated fluorination of aryltrifluoroborates with KF. The reaction proceeds under mild conditions (at 60 °C over 20 h) and shows a broad substrate scope and functional group tolerance. The Cu is proposed to play two separate roles in this transformation: (1) as a mediator for the aryl–F coupling and (2) as an oxidant for accessing a proposed Cu(III)(aryl)(F) intermediate.

Copper-Mediated Radiofluorination of Arylstannanes with [18F]KF

“…This work builds on recent reports from our group 6e,21 and others 6c,6f demonstrating a related Cu-mediated (radio)fluorination of arylboron precursors. In addition to the generally attractive features of arylstannane precursors discussed above, we anticipated that they would be particularly well suited for Cu-mediated radiofluorination.…”

Improving Transformations Through Organotrifluoroborates

“…Subsequently, the Sanford group reported an improved fluorination protocol that uses KF as a fluoride source and proceeds under mild reaction conditions that allow a variety of functional groups to be present on the aryl or heteroaryltrifluoroborate (Scheme 72) [106]. In addition to functional groups tolerated by the method employing NFTPT, this protocol allows the presence of aryl nitro and nitrile groups.…”

Transition Metal-Mediated and Metal-Catalyzed Carbon–Fluorine Bond Formation

“…in place of a N-fluorinated oxidant (Fig. 75) [182]. In this reaction, copper is hypothesized to play dual roles: as a redox-active mediator of C-F bond formation and as a stoichiometric oxidant.…”