US 9,052,592 B2  85  86  -continued  The term "-SO$_{2}$--containing cyclic group" refers to a  cyclic group containing a ring containing -SO$_{2}$ - in a ring  skeleton thereof, and specifically, it is a cyclic group in which  the sulfur atom (S) in -SO$_{2}$ - forms a part of the ring  skeleton of the cyclic group. When the ring containing  -SO$_{2}$ - in the ring skeleton thereof is counted as the first  ring, an -SO$_{2}$--containing cyclic group in which the only  ring structure is the -SO$_{2}$--containing ring is called a  monocyclic group, whereas an -SO$_{2}$--containing cyclic  group containing other ring structure is called a polycyclic  group regardless of the structure of the other rings. The  -SO$_{2}$--containing cyclic group may be either a monocy› clic group or a polycyclic group.  The -SO$_{2}$--containing cyclic group is especially prefer› ably a cyclic group containing---O-SO$_{2}$-in  a ring skeleton  thereof, namely a cyclic group containing a sultone ring in  which -O-S- in ---O-SO$_{2}$ - forms a part of the ring  skeleton.  More specifically, examples of the -SO$_{2}$--containing  cyclic group include groups represented by the following  general formulae (a5-r-1) to (a5-r-4), respectively.  [Chemical formula 3 7]  In the formulae, each Ra’ 15  independently represents a 65  hydrogen atom, an alkyl group, an alkoxy group, a halogen  atom, a halogenated alkyl group, a hydroxyl group,  Specific examples of each of the groups represented by the  general formulae (a5-r-1) to (a5-r-4) are given below. In the  following formulae, "Ac" represents an acetyl group.  The alkyl group, the alkoxy group, the halogen atom, the  halogenated alkyl group, --COOR", ---OC(=O)R", and the  hydroxyalkyl group in Ra’$^{51 }$are the same as those exemplified  in the description ofRa’$^{21 }$in the general formulae (a2-r-1) to  (a2-r-7).  In the general formulae (a5-r-1) to (a5-r-4), A" is the same  as A" in the general formulae (a2-r-2), (a2-r-3), and (a2-r-5).  --COOR", ---OC(=O)R", ahydroxyalkyl group, or a cyano  group; R" represents a hydrogen atom, an alkyl group, a  lactone-containing cyclic group, a carbonate-containing  cyclic group, or a -SO$_{2}$--containing cyclic group; A" rep- resents an alkylene group having 1 to 5 carbon atoms, which  may contain an oxygen atom or a sulfur atom, an oxygen  atom, or a sulfur atom; and n’ represents an integer of0 to 2.  (r-lc-7-1)  (a5-r-2)  (a5-r-3)  (a5-r-4)  *  HC  CH3  0-S:::::::, 0  II  0  (r-sl-1-5)  \~~H3  H~  0-S:::::::, 0  II  0  (r-sl-1-4)  *  XO  C  H3C  0-S:::::::, 0  II  0  (r-sl-1-3)  (r-sl-1-2)  *  0-S:::::::, 0  II  0  (r-sl-1-1)  [Chemical formula 38] 