The synthesis of biaryls through transition metal catalyzed cross-coupling reactions has been instrumental for synthetic organic chemists. The Hiyama reaction, which features organosilicon derived cross-coupling partners with aryl chlorides, remains relatively underdeveloped compared to other cross-coupling reactions. In this thesis, it is demonstrated that bench stable Palladium N-Heterocyclic Carbene (NHC) precatalysts of the general type [(NHC)Pd(allyl)Cl] are highly active in the Hiyama cross-coupling of activated aryl chlorides with low catalyst loading. Notably, this research demonstrates that catalysts featuring sterically less demanding NHCs display higher activity in this reaction, which contrasts with other cross-coupling reactions. Preliminary mechanistic investigations including in situ reaction monitoring by 19F NMR spectroscopy have uncovered side reactions. These side reactions may explain the low catalytic performance observed with unactivated substrates. These studies could help to further develop this reaction and improve catalytic performance. Additional investigations have also been made into ligand development by altering the electronics of sterically hindered NHC ligands for use in other cross-coupling reactions.
Author Keywords: Catalysis, Cross-coupling, Organic Chemistry, Organometallics, Side Reactions, Synthesis