Carboxylative Methodologies via Photoredox Catalysis

Carboxylic acids are a prominent class of molecules. Their use in pharmaceutical drug development is considered routine, given their intermediacy towards peptides and esters but also as target products. Over the last 15 years, method development for carboxylic acid synthesis in a catalytic fashion has witnessed tremendous efforts from the community. At the same time, the emergence of photoredox chemistry has allowed chemists to make new disconnections when building molecules.

The thesis aims to develop new carboxylating protocols from C1 molecules that would 1) grant access to previously unmet ways of making carboxylic acids from readily available alkyl halides, and 2) allow a radiochemist to access labeled structures promptly while building a molecular scaffold.

Three methodologies emerged from the work presented in this thesis. The first one, consisting of a multicomponent coupling of simple and available starting materials, gives access to a more advanced scaffold with labeled carboxylic acids. The second methodology is a photocatalytic reductive carboxylation of unactivated secondary alkyl bromides directly to their corresponding carboxylic acids. The third project is an extension of the second one, improving the system to avoid the use of CO₂ as a C1 source, preferring formic acid salts instead. The use of formic acid salts allows the reaction to be redox neutral, further avoiding the use of sacrificial reductants and was also used in the context of radiolabeling.