TRICARBONYLCHROMIUM(0) PROMOTED STEREOSELECTIVE TRANSFORMATIONS OF EPHEDRINE AND PSEUDOEPHEDRINE DERIVATIVES

Article abstract of DOI:10.1016/S0957-4166(00)80447-4

(-)-(1S,2S)-(N,O-Dimethylephedrine)tricarbonylchromium(0) (6) and (-)-(1S,2R)-(N,O-dimethylpseudoephedrine)tricarbonylchromium(0) (22) undergo completely stereoselective ortho deprotonation upon treatment with alkyllithium base, followed by addition of an electrophile.In both cases, exclusive remolval of the pro-(R)-ortho proton was confirmed by single 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.