Stereoselektive bildung von organoosmium-komplexen mit aminocarboxylat-liganden

Abstract The chelate osmium complexes {C 6 H 6 Os[OC(O)CH(R)N H 2 ](P i Pr 3 )}X ( 3 , 4 ) and {C 6 H 6 Os[OC(O)CH(R)N H 2 ](PMe t Bu 2 )}X ( 5–7 ) have been prepared almost quantitatively from [C 6 H 6 Os(PR 3 )I 2 ] precursors and α-aminocarboxylates. Owing to the NMR spectroscopic data, for l -alaninate as substrate one diastereoisomer and for d / l -phenylalaninate one pair of enantiomers is preferentially formed. The X-ray structural analysis of 6 (R = CH 3 ; X = I) confirms the presence of the R M S C diastereoisomer in the crystal lattice. The reaction of the five-coordinate chloro(hydrido)metal compounds [MHCl(CO)(PMe t Bu 2 ) 2 ] (M = Ru, Os) with glycinate and d / l -phenylalaninate gives the octahedral complexes { MH[OC(O)CH(R)N H 2 ](CO)(PMe t Bu 2 ) 2 ] ( 10–12 ) in 75–85% yield.