Selective Fmoc and Cbz protection of aromatic amino group in the presence of similar aliphatic function in liquid CO2

The selective protection of an aromatic amino group in the presence of aliphatic amino group in diamines by the action of FmocCl or CbzCl using liquid CO₂ as the solvent has been proposed. The developed method is preparative, does not require complex purification of the product, and meets the principles of green chemistry.