With new loopbacks on R1, R3, R4 and R7


R2#sh run | b Lo
interface Loopback1
 no ip address
 ipv6 address 2006:2:2::/128
!
ipv6 router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 area 20 virtual-link 3.3.3.3
 distribute-list prefix-list NoLoop out connected
 redistribute connected
 redistribute rip R2Rip tag 2
!
ipv6 router rip R2Rip
 redistribute connected route-map NoLoop
 redistribute ospf 1 metric 2
!
!
!
ipv6 prefix-list NoLoop seq 5 deny 2006:2:2::/128
ipv6 prefix-list NoLoop seq 10 permit ::/0 le 128
route-map NoLoop permit 10
 match ipv6 address prefix-list NoLoop
!
!