Light‐Mediated Formal Radical Deoxyfluorination of Tertiary Alcohols through Selective Single‐Electron Oxidation with TEDA2

The synthesis of tertiary alkyl fluorides through a formal radical deoxyfluorination process is described herein. This light‐mediated, catalyst‐free methodology is fast and broadly applicable allowing for the preparation of C−F bonds from (hetero)benzylic, propargylic, and non‐activated tertiary alcohol derivatives. Preliminary mechanistic studies support that the key step of the reaction is the single‐electron oxidation of cesium oxalates—which are readily available from the corresponding tertiary alcohols—with in situ generated TEDA2+. (TEDA: N‐(chloromethyl)triethylenediamine), a radical cation derived from Selectfluor®. C−F bond formation with no need for activation: The synthesis of tertiary alkyl fluorides through a formal radical deoxyfluorination process is described herein. This light‐mediated, catalyst‐free methodology is fast and broadly applicable allowing for the preparation of C−F bonds from (hetero)benzylic, propargylic, and non‐activated tertiary alcohol derivatives. Preliminary investigations support a very efficient radical chain mechanism in which TEDA2+. (TEDA: N‐(chloromethyl)triethylenediamine) is the key species.