Structural chemistry of methyl- and allylpalladium(II) complexes containing chiral thioether auxiliaries

The molecular structures of three Pd(11) compounds are reported: a) the two [PdCl(Me)] complexes 7a and 8a each containing a different chiral N,S-chelate based on ([(dihydrooxazolyl)phenyl]methyl)-thioglucose backbones, e.g., chloro([2-[(4S)-4,5-dihydro-4-isopiopyloxazol-2-yl-kappa N]phenyl]methyl 2,3,4,6-tetra-O-acetyl-1-(thio-kappa S)-beta-D-glucopyranoside)methylpalladium (II) (7a) and b) one [Pd(eta(3)-C(3)H(5))(PS)](+) cation in which the P,S-chelate stems from a phosphinofenocene and thioephedrine-derived thioether donor, i.e., [(S)-1-(diphenylphosphino-kappa P)-2-((1R)-1-{[(1R,2S)-1-phenyl-2-(piperidin-1-yl)propyl]thio-kappa S}ethyl)ferrocene] (eta(3)-prop-2-enyl)palladium trifluoromethanesulfonate (11). In the methylpalladium compounds 7a and 8a the thioglucose-kappa S moiety is pseudo-axial (Figs. 2 and 3),whereas in the allyl complex, the thioephedrine-kappa S moiety is markedly pseudo-equatorial (Fig. 5). It is suggested, based on these results, that the shape (chiral pocket) of such coordinated chiral thioethers may not be readily predictable.