| Abstract
| - The diastereomers (RM,SC)- and (SM,SC)-[(η6-cymene)M(LL*)X] (M = Ru, Os; LL* = salicylaldiminate anion; X = Cl, I), differing only in the labile metal configuration, crystallize partially as pure diastereomers and partially as 1:1 mixtures of the two diastereomers. The complexes serve as catalysts in the enantioselective isomerization of 2-n-butyl-4,7-dihydro-1,3-dioxepin (64% ee).
- Condensation of a number of optically active amines and α-amino acid esters withsalicylaldehyde gave the chiral compounds HLL*-1−HLL*-8. A series of diastereomericcomplexes of the type (RM,SC)- and (SM,SC)-[(η6-arene)M(LL*)X] (1−14: M = Ru, Os; X =Cl, I), differing only in the metal configuration, were formed by reaction of [(η6-arene)MCl2]2with these compounds in the presence of base and by halogen exchange. Five of the complexeswere characterized by X-ray structure analyses. Three cases showed the structural peculiaritythat the single crystals contained the RM,SC and SM,SC diastereomers with oppositeconfigurations at the metal centers in a 1:1 ratio, whereas two cases crystallized as pureRM,SC diastereomers. Two complexes, the ligands of which (the salicylaldiminates of methylphenylalaninate and methyl phenylglycinate) had racemized during the synthesis, crystallized as racemates RRu,SC/SRu,RC. Complexes 1−14 were tested as catalysts in the enantioselective isomerization of 2-n-butyl-4,7-dihydro-1,3-dioxepin to give 2-n-butyl-4,5-dihydro-1,3-dioxepin. Enantioselectivities up to 64% ee were achieved.
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