Carbon is the main element in all organic molecules and constitutes the main part of thousands of essential everyday materials such as pharmaceuticals, plastics, coatings, and dyes. However, most of the carbon employed to synthesize these chemicals comes from non-sustainable fossil resources such as oil, which society will run out of in the near future. Alternative sources of carbon are therefore urgently needed. An interesting example of a sustainable carbon feedstock is carbon dioxide (CO2). CO2 is a natural resource that has the potential to be used in chemical synthesis as a carbon source, but this requires the development of reactions that can efficiently convert CO2. The formation of C-CO2 bond using CO2 is particularly interesting, because C-C linkages constitute the core of all organic molecules. The project CATCHME will employ computational and experimental chemical methods to investigate, understand and develop C-CO2 bond formation using CO2. Focus will be on designing molecules that can capture CO2 and then promote selective and efficient C-CO2 bond formation.
CO2 is a natural resource that has the potential to be used in chemical synthesis as a carbon donor. This requires the development of CO2 conversion reactions, in particular towards C-CO2 bond formation, because C-C linkages constitute the core of all organic molecules. The project CATCHME will employ computational and experimental methods to investigate C-CO2 bond formation towards formation of chiral carboxylic acids. Three fundamental research questions will be studied:
- How does CO2 behave during C-CO2 bond formation?
- Can CO2 be trapped and activated towards C-CO2 bond formation?
- Can chiral CO2-trapping molecules promote asymmetric carboxylation?
C-C bond formation with CO2 typically involves metal-bound carbon nucleophiles. Recent research by us on C-CO2 bond formation indicates that in many reactions of this type, CO2 does not interact with the metal at the C-C bond formation step. CO2 thus experiences no activation from the metal centre. The unbound state of CO2 may be the reason that attempts towards enantioselective CO2 conversion often are unsuccessful, because the free CO2 is little affected by the chiral metal complexes that are employed. CATCHME proposes a novel strategy for enantioselective CO2 conversion, involving trapping of CO2 prior to C-C bond formation. Although many molecules are known that can trap CO2 (e.g. N-heterocyclic carbenes or frustrated Lewis pairs) they are typically employed in CO2 reduction or O-C bond formation, but not in C-C bond forming reactions. A critical aspect of CATCHME will be to identify CO2-adducts that are active in C-C bond formation. Further, if the adducts are chiral, this could provide a novel approach towards enantioselective C-C bond formation with CO2. CATCHME will employ high-level quantum chemistry methods to obtain general insights and identify promising trapping molecules, followed by organic chemistry approaches to test chiral CO2 trapping in enantioselective formation of carboxylic acids.