Treatment of the tricarbonyl(eta 6-o-trimethylsilylbenzaldehyde)chromium (O) complex with cyclic silyl enol ether species under the Mukaiyama condition resulted in highly stereoselective formation of syn-aldol products, whereas the aldol reaction with O-silyl ketene O,S-acetals afforded the corresponding anti-products in a highly stereoselective manner. The tricarbonyl(eta 6-o-trimethylsilyl-benzaldehyde)chromium(O) complex has also emerged as an excellent substrate for highly regio- and stereoselective construction of cis-3,5-isoxazolidine derivatives in the 1,3-dipolar cycloaddition reaction. By taking advantage of our newly developed aldol reaction, we have succeeded in highly stereocontroled syntheses of some biologically active compounds such as C-13 side chains of taxol and taxotère, the N-terminal amino acid of nikkomycin B and Bx, and antitumor styryllactones: goniofufurone, goniotriol, and goniothalenol.