Dehydration of 2-hydroxy-8-R-tricyclo[7.3.1.0(2.7)]tridecan-13-ones (R = H, Me, Ph) effected by various reagents provided 8-R-tricyclo[7.3.1.0(2.7)] tridecen-13-ones with different positions of the double bond. In the presence of phosphoric acid arise isomers with the double bond in 2(3) position, a mixture of hydrochloric and acetic acid primarily affords isomers with the double bond in 2(7) position that further migrates into 7(8) position at R = Me, Ph.