if you have a lease on a building and the building burns down, the leasor is paid by the insurance company to put the building back up but chooses to sell the building what rights do the leasee have being that he/she has a 5 year lease

Well, none, unless it was given to you in your leasing contract.

But under YOUR property policy, as a tenant, there's a coverage to protect you in case something like that happens. It pays the rental difference between the old lease, and the new lease for similar quality/space, for the remainder of the lease period.

You should check with your agent to be sure you have LEASEHOLD coverage.