Palladium-catalyzed ortho-selective C–H fluorination of oxalyl amide-protected benzylamines.

A novel and efficient synthetic method for o-fluorobenzylamines via palladium catalyst using an easily accessible oxalyl amide as directing group has been developed. The cheap N-fluorobenzenesulfonimide could be used as an effective [F+] source and t-amyl-OH as the solvent with Pd(OAc)2 as catalyst. Selective mono- or difluorination of oxalyl amide-protected benzylamine derivatives were achieved by modifying the reaction conditions, which presented an efficient method for the preparation of ortho-fluorinated benzylamines.