Atom-economy in green organic synthesis

Atom economy is the second of the 12 green chemistry principles. This principle is particularly useful for the synthesis of fine organic chemicals and active pharmaceutical ingredients. The power of this principle comes from its quantifiable nature. Moreover, this metric can be applied at the stage of the synthesis planning prior to real experiments. However, atom economy as a sole criterion of the process greenness is deficient and should be applied for such assessments together with other principles. Being very important for the design of synthesis routes, atom economy may turn into a minor contributor to the overall greenness of a synthesis when experimental results become available. This chapter illustrates the role of atom economy in the synthesis of three important medicines (ibuprofen, praziquantel, and sildenafil citrate) via different synthetic routes, including commercial ones.