Abstract:
N-heterocyclic carbenes (NHCs) have undergone rapid development in recent years.
Due to their strong a-electron donation and structural variability properties, NHCs are
becoming a major class of ligands in organometallic chemistry.
Compared with the other two types of NHCs (imidazolylidenes and
imidazolinylidenes), benzimidazolylidenes have not been well represented. Limited
synthetic approaches may impede the development ofbenzimidazolylidenes.
This thesis is focused on the synthesis of phenanthroline-derived benzimidazolylidene
ligands and their metal complexes. A series of benzimidazolylidene-iridium complexes
were synthesized and characterized spectroscopically and crystallographic ally. All of the
new complexes showed varying degrees of catalytic activity and enantioselectivity toward
transfer hydrogenation and asymmetric hydrogenation. The best results were achieved in
hydrogenation of methyl-2-acetamidoacrylate, which afforded
(-)-(R)-methyl-2-acetamidopropanoate in 97% yield and 81 % ee.
