Challenges in Catalysis for Pharmaceuticals and Fine Chemicals II Formation of C-C Bonds via Catalytic Hydrogenation and Transfer Hydrogenation
Alkene hydroformylation is the largest volume application of homogenous metal catalysis and the prototypical C-C bond forming hydrogenation. Despite the impact of hydroformylation, systematic efforts to generalize this process are absent. The Krische group has developed late transition metal catalysts that promote direct reductive C-C coupling of π-unsaturated reactants to carbonyl compounds and imines under hydrogenation conditions, offering a byproduct-free alternative to stoichiometric organometallic reagents in a range of classical C=X (X = O, NR) addition processes. This concept is extended further via C-C bond forming transfer hydrogenation - reactions in which an alcohol serves dually as hydrogen donor and precursor to the carbonyl electrophile, enabling carbonyl addition directly from the alcohol oxidation level in the absence of pre-metallated nucleophiles.