Metallkomplexe mit biologisch wichtigen Liganden, CLXI [1]. Halbsandwich-Komplexe mit tert-Leucin, Dipeptiden, Pentaglycin und Glutathion als Liganden / Metal Complexes with Biologically Important Ligands, CLXI [1]. Halfsandwich Complexes with tert-Leucine, Dipeptides, Pentaglycine and Glutathione

Abstract

Reactions of L-tert-Leucine (tert-butylglycine), tert-leucine methyl ester, GlyValOMe, and Leu- AlaOMe with the chloro-bridged complexes [Cp*IrCl2]2, [(p-cymene)RuCl2]2 or [(C6Me6)RuCl2]2 in the presence of NaOMe give the complexes [Cp*Ir(Cl)NH2CH(R)CO2] (1), [(p-cymene)Ru(Cl)- NH2CH(R)CO2] (2), Cp*Ir(Cl2)[NH2CH(R)CO2Me] (5), {(C6Me6)Ru(Cl)[NH2CH2CONHCH(R)- CO2Me]}+Cl− (6), [Cp*Ir(Cl)NH2CH2CONCH(R)CO2Me] (7), [Cp*Ir(Cl)NH2CH(CH2CHMe2)- CONCH(R)CO2Me)] (8), and Cp*Ir(Cl2)[NH2CH2CONHCH(R)CO2Me) (9). With pentaglycine the complexes [Cp*Ir(Cl2)(pentaglycinate+Na+)] (10) and [(C6Me6)Ru(pentaglycineOMe- H+)] (11) could be isolated. Coordination of one equivalent of the S-protected tripeptide glutathione to [Cp*Ir(Cl)] and to [(C6Me6)Ru(Cl)] was observed. Some in situ prepared (p-cymene)Ru complexes with deprotonated dipeptide esters were tested as catalysts and the complex [(p-cymene)Ru(Cl)(NH2CH(CHMeEt)NCH (CHMe2)CO2tert-Bu)] gave a yield of 73% and moderate entantiomeric excess (36% ee) in the transfer hydrogenation of acetophenone to 2-propanol.