ISOLATION AND STRUCTURAL CHARACTERIZATION OF ENANTIOMERICALLY PURE PLANAR CHIRAL CYCLOPALLADATED DERIVATIVES OF FERROCENYLIMINES

Reaction of ferrocenecarboxaldehyde with (+)-(R)-1-amino-2-(methoxymet hyl)pyrrolidine [(+)-(R)-1] and (-)-(S)-1-amino-2-(methoxymethyl)pyrro lidine [(-)-(S)-1] in dry benzene gave new chiral ferrocenylimines (-) -(R)-FcCH=NNCH2CH2CH2CHCH2OCH3 [(-)-(R)-2] and (+)(S)-FcCH=NNCH2CH2CH2 CHCH2OCH3 [(+)-(S)-2], respectively. Asymmetric cyclopalladation of (- )-(R)-2 and (+)-(S)-2 with sodium tetrachloropalladate(II) and sodium acetate trihydrate in methanol at room temperature gave a mixture of d iasteromeric cyclopalladated products (+)-(S-p,R)-[PdCl(eta(5)-C5H3CH= NNCH2CH2CH2 CHCH2OCH3)Fe(eta(5)-C5H5)] [(+)-(S-p,R)3], ta(5)-C5H3CH=NN CH2CH2CH2CHCH2OCH3)Fe(eta(5)-C5H5)] [(-)-(R-p,R)-3] and ta(5)-C5H3CH=N NCH2CH2CH2CHCH2OCH3)Fe(eta(5)-C5H5)] [(-)-(R-p,S)-3], ta(5)-C5H3CH=NNC H2CH2CH2CHCH2OCH3)Fe(eta(5)-C5H5)] [(+)-(S-p,S)-3] in ca. 75% yield wi th a high level of diastereoselectivity, respectively. The four enanti opure compounds were isolated from the two mixtures through column-lay er chromatography. Their relationship was elucidated by NMR, optical r otation, and single-crystal X-ray analysis.