Jul. 21, 2016  18  US 2016/0209749 Al  benzofuran residue, and benzothiophene residue. In a case  where the arylsulfonium compound has two or more aryl  groups, the two or more aryl groups may be the same as or  different from each other.  [0315]  An alkyl group or a cycloalkyl group which the  arylsulfonium compound has according to necessity is pref› erably a linear or branched alkyl group having  1  to 15 carbon  atoms or a cycloalkyl group having 3 to 15 carbon atoms, and  examples thereof include a methyl group, an ethyl group, a  propyl group, an n-butyl group, a sec-butyl group, at-butyl  group, a cyclopropyl group, a cyclobutyl group, and a cyclo› hexyl group.  [0316]  The aryl group, the alkyl group, and the cycloalkyl  group represented by each ofR$_{201 }$to R$_{203 }$may have an alkyl  group (having  1  to 15 carbon atoms, for example), a  cycloalkyl group (having 3 to 15 carbon atoms, for example),  an aryl group (having 6 to  14  carbon atoms, for example), an  alkoxy group (having  1  to 15 carbon atoms, for example), a  halogen atom, a hydroxyl group, or a phenylthio group, as a  substituent.  [  0317]  Next, the compound (ZI-2) will be described.  [0318]  The compound (ZI-2) is a compound in which each  ofR$_{201 }$to R$_{203 }$in Formula  (ZI)  independently represents an  organic group not having an aromatic ring. The aromatic ring  herein also includes an aromatic ring containing a hetero  atom.  [0319]  The organic group not containing an aromatic ring  represented by each of R$_{201 }$ to R$_{203 }$ generally has  1  to 30  carbon atoms, and preferably has  1  to 20 carbon atoms.  [0320]  Each ofR$_{201 }$to R$_{203 }$independently preferably rep› resents an alkyl group, a cycloalkyl group, an ally! group, or  a vinyl group, more preferably a linear or branched  2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycar› bonylmethyl group, and particularly preferably a linear or  branched 2-oxoalkyl group.  [0321]  Preferable examples of the alkyl group and the  cycloalkyl group represented by each ofR$_{201 }$to R$_{203 }$include  a linear or branched alkyl group having  1  to  10  carbon atoms  (for example, a methyl group, an ethyl group, a propyl group,  a butyl group, or a pentyl group) and a cycloalkyl group  having 3 to  10  carbon atoms (a cyclopentyl group, a cyclo› hexyl group, or a norbomyl group).  [0322]  Each ofR$_{201 }$to R$_{203 }$may be further substituted with  a halogen atom, an alkoxy group (which has  1  to 5 carbon  atoms, for example), a hydroxyl group, a cyano group, or a  nitro group.  [0323]  Next, the compound (ZI-3) will be described.  [0324]  The compound (ZI-3) is a compound which is rep› resented by the following General Formula (ZI-3) and has a  phenacylsulfonium salt structure.  (ZI-3)  [0325]  In General Formula (ZI-3), each ofR$_{1}$c to R$_{5}$c inde› pendently represents a hydrogen atom, an alkyl group, a  cycloalkyl group, an aryl group, an alkoxy group, an aryloxy  group, an alkoxycarbonyl group, an alkylcarbonyloxy group,  a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl  group, a nitro group, an alkylthio group, or an arylthio group.  [0326]  Each of R 6 c and R$_{7}$c independently represents a  hydrogen atom, an alkyl group, a cycloalkyl group, a halogen  atom, a cyano group, or an aryl group.  [0327]  Each of  Rx  and  RY  independently represents an alkyl  group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocy› cloalkyl group, an alkoxycarbonylalkyl group, an ally! group,  or a vinyl group.  [0328]  Any two or more ofRlc to Rsc, Rsc and R6c, R6c and  R$_{7}$c, R$_{5}$c and  Rx,  and  Rx  and  RY  may be respectively bonded to  each other to form a ring structure, and the ring structure may  include an oxygen atom, a sulfur atom, a ketone group, an  ester bond, or an amide bond.  [0329]  Examples of the ring structure include an aromatic  or non-aromatic hydrocarbon ring, an aromatic or non-aro› matic heterocycle, or a polycyclic condensed ring formed by  combination of two or more of these rings. Examples of the  ring structure include 3- to IO-membered rings, and among  these,  4- to 8-membered rings are preferable, and 5- or  6-membered rings are more preferable.  [0330]  Examples of the group formed by bonding of any  two or more ofR$_{1}$c to R$_{5}$c, R 6 c and R$_{7}$c, or  Rx  and  RY  to each  other include a butylene group and a pentylene group.  [0331]  As the group that R$_{5}$c and R 6 c, and R$_{5}$c and  Rx  respectively form by bonding to each other, a single bond or  an alkylene group is preferable, and examples of the alkylene  group include a methylene group and an ethylene group.  [0332]  zc- represents a non-nucleophilic anion, and as  zc-,  the same as the non-nucleophilic anion represented by z- in  General Formula  (ZI)  can be exemplified.  [0333]  Specific examples of the alkoxy group in the alkoxy› carbonyl group represented by each ofR$_{1}$c to R$_{5}$c are the same  as the specific examples of the alkoxy group represented by  each ofR$_{1}$c to R$_{5}$c described above.  [0334]  Specific examples of the alkyl group in the alkylcar› bonyloxy group and the alkylthio group represented by each  ofR$_{1}$c to R$_{5}$c are the same as the specific examples of the alkyl  group represented by each ofR$_{1}$c to R$_{5}$c described above.  [0335]  Specific examples of the cycloalkyl group in the  cycloalkylcarbonyloxy group represented by each of R$_{1}$c to  R$_{5}$c are the same as the specific examples of the cycloalkyl  group represented by each ofR$_{1}$c to R$_{5}$c described above.  [0336]  Specific examples of the aryl group in the aryloxy  group and the arylthio group represented by each ofR$_{1}$c to R$_{5}$c  are the same as the specific examples of the aryl group rep› resented by each ofR$_{1}$c to R$_{5}$c described above.  [0337]  Examples of the cation in the compound (ZI-2) or  (ZI-3) in the present invention include the cations described  in paragraphs "0036" and later ofUS2012/0076996A.  [0338]  Next, the compound (ZI-4) will be described.  [0339]  The compound (ZI-4) is represented by the follow› ing General Formula (ZI-4).  (ZI-4) 