NCC-1701 Kirk blew it up using the auto-destruct over the Genesis Planet to prevent it from falling into enemy hands.
NCC-1701-A Was retired from service after the events of Star Trek VI: The Undiscovered Country
NCC-1701-B Unknown, but likely was retired after service.
NCC-1701-C Was destroyed defending a Klingon outpost.
NCC-1701-D Was destroyed by a warp-core breach after an attack by a Klingon Bird of Prey during the Nexus incident in Star Trek Generations.
NCC-1701-E Still in service.
Daniels, the temporal agent, reveals in the Enterprise episode "Azati Prime" that there will go on to be Enterprise-J