The invention related to a novel process, novel process steps and novel intermediates useful in the synthesis of pharmaceutically active compounds, especially renin inhibitors, such as Aliskiren. Inter alia, the invention relates to a process for the manufacture of a compound of the formula III, wherein R, R1, and R′ are as defined in the specification, or a salt thereof, and a compound of formula IV wherein R, R1, R2 and R′ are as defined in the specification, and processes of manufacturing these.