| Popis: |
(−)-(1 S ,2 S )-( N ,O-Dimethylephedrine)tricarbonyl chromium(0) (6) and (−)-(1 S ,2 R )-( N ,O-dimethylpseudoephedrine)tricarbonylchiromium(0) ( 22 ) undergo completely stereoselective ortho deprotonation upon treatment with alkyllithium base, followed by addition of an electrophile. In both cases, exclusive removal of the pro -( R )- ortho proton was confirmed by single crystal X-ray structure analyses of the methylated products. Addition of methyllithium onto the ortho -formylated derivative of complex ( 6 ) occurs stereoselectively, the stereochemistry of the major product being confirmed by a single crystal X-ray structure determination. The results presented demonstrate an efficient transfer of chirality from a side chain onto the (arene)tricarbonylchromium(0) complex and back to a different side chain. |
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