Chirale P,N- und P,P-Liganden : Synthese und Anwendungen in der asymmetrischen Katalyse

In this Ph.D. work, different new P,N-ligands were synthesized based on cyclohexane-1,2-
diamine and 1,2-diphenylethylenediamine. These chiral diamines were first arylated or
alkylated at the nitrogen atoms, then treated with PCl3 and finally coupled with the
oxazoline alcohol 15. Complexation of the ligands with [Ir(COD)Cl]2 followed by anion
exchange with NaBArF gave the corresponding catalysts 32 to 38.
All the catalysts were tested in the hydrogenation of prochiral olefins leading in most of
the cases to full conversion and good stereoselectivities.
his type of P,N-ligand was very successful, specially in the hydrogenation of α,β-
unsaturated aryl- or alkyl-substituted esters. α- and β-methylcinnamic acid ethyl ester as
well as (E)- and (Z)-ethyl 3-methyl-5-phenylpent-2-enoate could be hydrogenated with
enantiomeric excesses superior to 88% and in the case of benzyl tiglate 72% ee were
obtained.
Another part of this Thesis concerned the preparation of different achiral and chiral
ferrocenyl phosphines. These were selectively deprotonated with alkyllithium either in
ortho- or meta-position, depending on the phosphorus substituents.
NMR-experiments on (Sp)-202BH3 and on (Rp)-200BH3 gave some insight into the
different dynamics of the lithiated intermediates. Some informations about the
coordination of the lithium in (Rp)-200BH3 could be acquired.