Stereoselective synthesis of sugar allenes and their hydrosilylation catalyzed by biscobaltoctacarbonyl

Stereoselective introduction of allenyl group to glycals has been developed with propargyltrimethylsilane under the catalysis of a Lewis acid to produce largely the α-sugar allenes in good yields. The subsequent hydrosilylations of these sugar allenes were catalyzed by biscobaltoctacarbonyl to obtain the corresponding vinylsilanes. Stereochemical selectivity is also discussed.