Bovina eased past Dementieva, 6-1, 6-1, at the Connecticut Tennis Center at Yale. The Moscow native will take on Nathalie Dechy in the title match.
Dechy defeated Lisa Raymond, 6-4, 6-0, in the other semifinal.
Dechy and Bovina have split two previous meetings.
The 21-year-old Bovina is seeking her third career title.