By Staff Construction is underway on a 100,000-square-foot office complex that will bring group benefits company Sun Life Financial Inc. to Portland’s growing business district on the eastern waterfront. Representatives of Sun Life (NYSE: SLF), developer Portland Foreside and public officials held a virtual groundbreaking ceremony Tuesday to celebrate the start of the building at 58 Fore St., on the former Portland Co. complex. Sun Life has 500 employees at offices in Scarborough and South Portland, and will occupy about 77,000 square feet of the building. It’s expected to be complete in 2022. The project, announced in September 2019, will ultimately also include dining, hospitality and entertainment venues, and a feature never before available to the city — direct access to the waterfront through scenic public park plazas.