One of the largest multifamily projects to break ground in Boston’s South End in recent years is marketing units in its first apartment building which is scheduled to open next spring.

Crews from construction manager Suffolk this week topped off the first 299-unit building at The Smith. The project, built on former Boston Medical Center properties spanning over 3 acres, will total 650 units.

Developers launched a website this week. Rents have not been announced, but the site is accepting signups for a mailing list to provide updates to prospective tenants.

Designed by CBT Architects, The Smith is a joint venture between Boston-based Leggat McCall Properties and BentallGreenOak’s U.S. Core Fund. The property will be managed by Greystar.

Amenities include a roof deck pool, fitness and yoga rooms, a pet wash and run, and co-working spaces. The project also will include nearly 77,000 square feet of office space and 19,700 square feet of retail and cultural space.

Leggat McCall acquired the six South End parcels at 660 and 720 Harrison Ave., 575 Albany St., 100 East Canton St. and 123 East Dedham St. in January 2015.