text:  With highly electron withdrawing <unk> substituents , <unk> exhibit reactivity more similar to that of <unk> than typical <unk> . Notably , <unk> <unk> certain C @-@ H bonds with high selectivity . <unk> <unk> may be synthesized by subjecting a perfluorinated imine to <unk> <unk> peroxide and a metal fluoride to act as an HF scavenger . 
  