DEVELOPMENT OF N-HETEROCYCLIC CARBENE AND PHOSPHINE LIGANDS FOR TRANSITION METAL CATALYSIS

N-Heterocyclic carbenes (NHCs) along phosphines have emerged as powerful class of ancillary ligands for transition-metal-catalysis in a broad range of fundamental organic transformations, including cross-coupling and alkene metathesis. NHC ligands show unique advantages in valuable synthetic transformations owing to their inherent properties such as strong s-donation and readily modifiable steric environment. The design and development of novel NHC ligands is in high demand in various areas of organic, organometallic and inorganic chemistry to expand the toolbox of transition metals for catalysis by stabilization of reactive metal centers. This thesis includes: (1) the development of highly hindered CAAC–IPr* ligands with enhanced steric and electronic properties for copper-catalyzed hydroborylation; (2) the development of novel twisted amide Xantphos phophine ligands with tunable geometries for transition-metal-catalyzed C–C, C–P, and C–B bond-forming reactions; (3) the development of hemilabile N-Heterocyclic carbene-Pym ligands for gold catalyzed hydroarylation, including late-stage derivatization of pharmaceuticals; (4) the development of hemilabile N-Heterocyclic carbene-Pym ligands for gold-catalyzed hydroamination with ultra-low catalyst loading; (5) the development of spiro-NHC ligands for gold-catalyzed deoxygenation of amides with broad substrate scope.