The use of metal catalysts is key for many chemical industrial processes. Many of these rely on noble metals which, despite their excellent performance, are scarce and present environmental and societal challenges. Thus, the development of alternative and sustainable synthetic protocols are of utmost importance. Transitioning to abundant metals, such as first-row transition metals (also known as base metals), is the most logical and preferred strategy. However, this transition is not straightforward due to the different reactivity that these metals present. Another strategy to minimize the impact of noble metals is to use them in a more efficient manner.

The work of this thesis contributes to the development of synthetic methods for organic chemistry motivated by sustainability aspects. The strategies explored were transitioning to base metal catalysis, use of light and electricity as energy sources, and the immobilization of homogeneous catalysts. First, a method was developed using an iron complex for the synthesis of allenylboronates from propargyl acetates. Secondly, a heterogeneous photocatalyst PCN-222(Pd) was developed and used for the aerobic cross-condensation of amines. Thirdly, the immobilization of Ru(BINAP)(OAc)₂ on cellulose was developed and used for the asymmetric hydrogenation of aliphatic α,β-unsaturated carboxylic acids. Finally, the use of nickel foam as electrocatalyst for the hydrogenation of alkenes was investigated and compared with the traditional Pd/C and H₂ gas method via life cyle, toxicological and safety assessments. 

Although catalysis is a tool that can assist in achieving this goal, it is important to highlight that many other aspects require attention, such as recyclability, the use of greener solvents, transition to renewable feedstocks like bio-ethanol, and shorter synthetic protocols, to name a few.

Finally, it is important to understand that addressing all the sustainability aspects of an organic chemistry process is very challenging. However, the improvement of part of these aspects can contribute to the development of a sustainable chemistry in a step-wise manner.