Reductive functionalization of CO2 with amines: an entry to formamide, formamidine and methylamine derivatives

CO2 utilization for the production of C-1- containing molecules is a desirable route to value-added chemicals. In this perspective, we summarize the recent results devoted to the formation of nitrogen compounds obtained by reductive functionalization of CO2 in the presence of amines. Using mild reductants, such as molecular hydrogen, hydrosilanes and hydroboranes, novel catalytic reactions have been designed in the last few years to facilitate the reductive functionalization of CO2 to formamide, formamidine and methylamine derivatives. While early efforts were devoted to the formylation of N-H bonds, efficient organic and metal catalysts have been developed lately to promote the complete deoxygenation of CO2 to benzimidazoles, quinazolinones, formamidines and methylamines. Finally, the opportunities and challenges facing the practical use of CO2 in the production of nitrogen-containing molecules are discussed.