Unexpected formation of N-fluoroalkaneacyl anilides from the reactions of fluoroalkanesulfonyl azides with nitrobenzene and its derivatives

The thermal reactions of fluoroalkanesulfonyl azides RfCF2SO2N3 1 with nitrobenzene and its derivatives XC6H4NO2 (X=H, F, Cl, CF3) gave the unexpected N-fluoroalkaneacyl anilides RfCONHC6H4X (X=H, Cl, F, CF3) in addition to fluoroalkanesulfonyl amides RfCF2SO2NH2. Under the same reaction conditions, however, nitrobenzene containing an electron-donating group RC6H4NO2 (R=CH3, OCH3) reacted with 1 affording the corresponding N-fluoroalkanesulfonyl anilides RfCF2SO2NHC6H3(NO2)R. Other electron-poor benzene derivatives, such as benzaldehyde, benzoate, and acetophenone C6H5Y(Y=CHO, COCH3, CO2CH3) all gave the meta-substituted N-fluoroalkanesulfonyl anilides RfCF2SO2NHC6H4Y.