ASYMMETRIC CATALYSIS - COMPARISON OF THE ENANTIOSELECTION OF RHODIUM-CATALYZED INTRAMOLECULAR HYDROSILATION AND HYDROACYLATION

The previously reported observation that 4-pentenals bearing either a tertiary group or acyl or ester substituents at the 4-position gave ve ry high ee's for hydroacylation using the [Rh(S-binap)(solvent)(2)](+) catalyst suggested that the same catalyst might give high ee's for in tramolecular hydrosilation of similarly substituted allylic alkoxides bound to diaryl- or dialkylsilanes. Although the chemical yields and e e's are dependent on the solvent used and on the olefin and silicon su bstituents, there are combinations of these parameters which lead to h igh ee's for hydrosilation of substrates bearing these substituents,