From: Rabbi Moshe Sofer
To: Rabbi Wolf
The Chasam Sofer rules that rented synagogues possess full kedushas beis haknesses for the duration of the lease. The landlord's theoretical ability to revoke the lease does not undermine the community's present rights, just as a buyer's redemption right does not prevent consecration of a sdeh miknah; moreover, if the landlord consented to construction of the synagogue, the consecration is entirely uncontested.
Source: Shu"t Chasam Sofer YD §225