Three new optically pure C1-terpyridine ligands (L1-3) were prepared and the copper(II) complexes, of formula [Cu(L)Cl2], the rhodium(III) complexes, of formula [Rh(L)Cl3], and the ruthenium(II) complexes, of formula cis- or trans-[Ru(L)(X)Cl2] (X = DMSO or CO), were synthesized. Structures of a chiral C1-ligand, a copper complex, a rhodium complex and a ruthenium DMSO complex were analysed using X-ray crystal structure analysis. The copper, rhodium and ruthenium complexes were shown to be precursors of catalysts for cyclopropanation. Reaction of [Cu(L)Cl2], [Rh(L)Cl3] or cis- or trans-[Ru(L)(X)Cl2] with AgOTf converted the complex to catalyst, which in the case of trans-[Ru(L)(CO)Cl2] gave enantioselectivities of up to 67% ee for the cis-isomers of styrene cyclopropanes with t-butyl diazoacetate. Comparisons with C2-analog of copper, rhodium and ruthenium catalysts were made.
Scopus Subject Areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry
- Asymmetric catalysis
- Chiral terpyridine
- Metal-catalyzed cyclopropanation