The company is setting-up a joint venture with freeholder Grosvenor to redevelop the site as a hotel and residential complex.
The 1960s office block on the site is currently owned by Derwent London and Grosvenor and is used as offices.
Derwent has now confirmed plans to sell its 50% stake to Peninsula Hotels for £132.5m.
Derwent said: “It is intended that, following the disposal of Derwent London’s interest, Peninsula Hotels and Grosvenor will work together towards redevelopment of the site as an hotel and residential scheme.”