195  US 9,291,896 B2  196  -continued  -continued  0  0  ---._J  II  II  j’o  I  I  O  O  O~N  #  H  OBu  ~  vy  6  0  0  II  II  (PA-96)  0  0  H2N  (PA-97)  (PA-98)  (PA-100)  rY\  ~  0  0  II  II  M’N.,,,  (PA-101)  (PA-102)  0  0  F  F  H  II  ll™F  N  S  S  ’-..../ll’N/11  F  0  0  F  F  F  F  In the present invention, a compound (PA) other than the  compound capable of generating a compound represented by  formula (PA-1) can be also appropriately selected. For  example, a compound that is an ionic compound and has a  proton acceptor site in the cation moiety may be used. More  specifically, examples of such a compound include a com› pound represented by the following formula (7):  In the formula, A represents a sulfur atom or an iodine  atom.  m represents 1 or 2, and n represents 1 or 2, provided that  when A is a sulfur atom, m+n=3 and when A is an iodine atom,  m+n=2.  R represents an aryl group.  RN  represents an aryl group substituted with a proton  acceptor functional group.  x- represents a counter anion.  Specific examples of  x- are the same as those of x- in  formula (ZI).  Specific preferred examples of the aryl group ofR and  RN  include a phenyl group.  (7) 