Work will commence on three schemes as part of the £655m ($1.06m) London West End development of Land Securities.
The three schemes include Park House on Oxford Street, and Selborne House and Wellington House on Victoria Street.
The mixed-use Park House scheme, designed by Hamilton Associates, will comprise 15,140m² of office space, 8,140m² of retail space and 5,380m² of residential space. It will occupy the second to seventh floors.
Mace will begin construction works on the site in May, with completion scheduled for November 2012.
The sustainable Selborne House will feature 11 floors including 23,450m² of office space and 1,540m² of ground-floor retail.
The scheme has been jointly designed by Pelli Clarke Pelli Architects and Swanke Hayden Connell, and will be delivered by Sir Robert McAlpine.
Construction is expected to start on site later this year and will be complete by July 2013.