Osmium complexes amino acids

For convenience we deal with all the reported osmium complexes of amino acids in this section, apart from the osmyl species (p. 583). 

Osmium complexes, 519-619 alkaloids, 569 alkoxo, 596 amido, 557 amines, 557 bidentate, 530 monodentate. 530 amino acids, 602... 

Moreover, the authors reasoned that electron-withdrawing substituents R (e.g., R = CF3) on 0s02(NR)2 facilitate the cycloaddition step, whereas the reoxidation of Os(VI) to Os(Vlll) is hindered. For electron-donating substituents R (R = —Me, tert-Bu), the opposite behavior was predicted. The coordination of a chiral amino ligand (which might transfer stereochemical information) turned out to be hardly feasible due to the reduced Lewis acidity of the bisimido osmium complexes. All bisimido dioxo osmium compounds were calculated to be thermodynamically instable toward hydrolysis, with the degree of stability depending on the substituents R (Table 6). 

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