Divergent Synthesis of α-Fluorinated Carbonyl and Carboxyl Derivatives by Double Electrophilic Activation of Amides.

A straightforward and divergent entry to α-fluorinated carbonyl and carboxyl derivatives is reported. Upon activation of amides with triflic anhydride and a 2-halo-pyridine and subsequent trapping of the resulting keteniminium ions with nucleophiles followed by a second electrophilic activation with NFSI and final hydrolysis, a range of amides can be transformed to α-fluorinated ketones, esters, and amides under mild conditions. Moreover, this reaction can be performed to yield enantioenriched products with a traceless chiral auxiliary.