Addition-fragmentation agents of the formula are disclosed:whereinR4 is hydrogen, a C1 to C4 alkyl group,x is 1 or 2,R5 is a di- or trivalent (hetero)hydrocarbyl linking group,-A*-X2*- is a group formed between A and X2, wherein X2 comprises an electrophilic or nucleophilic functional group and A is a functional group that is co-reactive with functional group X2, andn is 0 or 1.
