The reaction of F4S = activated CCF2OSO2 with ROH (R = CH3, CH(CH3)2, C(CH3)3), ClX (X = F, OCF3) and CsOCF3 was studied as a means for preparing novel sulfonyl fluorides or sultones. The new beta-fluoro sultones CH3OSF4 activated CHCF2OSO2 and F5S activated C(Cl)CF2OSO2 were prepared and characterized.