Access to Trifluoromethylketones from Alkyl Bromides and Trifluoroacetic Anhydride by Photocatalysis.

Abstract

Aliphatic trifluoromethyl ketones are a type of unique fluorine-containing subunit which plays a significant role in altering the physical and biological properties of molecules. However, catalytic methods to provide direct access to aliphatic trifluoromethyl ketones is highly desirable yet remains underdeveloped, partially due to the high reactivity and instability of trifluoroacetyl radical. Herein, we report a photocatalytic synthesis of trifluoromethyl ketones from alkyl bromides with trifluoroacetic anhydride. The reaction features a dual catalysis of visible-light and XAT reaction, followed by an enabling radical-radical cross-coupling of alkyl radical with a stabilized trifluoromethyl radical. The reaction provides the first straightforward access to aliphatic trifluoromethyl ketones from easily-available and cost-effective alkyl halides and TFAA.