A compound represented by formula (I):
wherein, in formula (I), R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atom(s); Ra represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group; X represents a halogen atom, or an alkyl- or aryl-sulfonyloxy group; L represents a divalent linking group; Z represents a (n+1)-valent organic group; and n represents an integer of 1 to 6, a plurality of Rs and Ras and Xs may be the same or different from each other, respectively, and when n represents 2 to 6, a plurality of Ls may be the same or different from each other.