 Triflic anhydride

Triflic anhydride is $(\mathrm{C}{\mathrm{F}}_3\mathrm{S}{\mathrm{O}}_2{)}_2\mathrm{O}$, an electrophilic sulfonylating reagent. carbonyl oxygen attack can form an O-triflylated intermediate; adjacent nitrogen donation gives an imidoyl-triflate description.