Tricarbonylchromium complexes of four methyl 4,6-O-[(eta(6)-phenyl)alkylidene]-alpha-D-glucopyranosides

The crystal structures of the chiral non-racemic eta(6)-tricarbonylchromium complexes of three methyl 4,6-O-benzylidene-alpha-D-glucopyranosides, (1)- (3), have been determined, as well as that of the 4,6-O-acetal, (4), derive d from acetophenone. These compounds are tricarbonyl{(R)-methyl 2,3-di-O-me thyl-4,6-O-[(1S,3R)(eta(6)-3-trimethylsilylphenyl)methylene]-alpha-D-glucop yranoside}chromium(0), (1), [Cr(C19H30O6Si)(CO)(3)], tricarbonyl{(R)-methyl 2, 3-di-O-methyl-4, 6-O-[(1S, 2R)-(eta(6)-2-trimethylsilylphenyl)methylene ]-alpha-D-glucopyranoside}chromium(0), (2), [Cr(C19H30O6Si)(CO)3], tricarbo nyl{(R)-methyl 2,3-O-(1-methylethylidene)-4,6-O-[(eta(6)-phenyl)methylene]- alpha-D-glucopyranoside}chromium(0), (3), [Cr(C17H22O6)(CO)(3)], and tricar bonyl{(S)-methyl 2,3-di-O-methyl-4,6-O-[(eta(6)-1-phenyl)ethylene]-alpha-D- glucopyranoside}chromium(0), (4), [Cr(C17H24O6)(CO)(3)].