Selective Hydrosilylation of 1,3-Diynes Catalyzed by Titania-Supported Platinum

Titania-supported platinum (mainly as Pt­(II)) has been
found to
effectively catalyze the hydrosilylation of 1,3-diynes at 70 °C
with low catalyst loading (0.25 mol %) under solvent-free conditions.
Monohydrosilylation was achieved for diaryl-substituted diynes, whereas
dialkyl-substituted diynes were transformed into the corresponding
dihydrosilylated products in good yields. In every case, the process
was proven to be highly stereoselective, with syn addition of the
silicon–hydrogen bond, and regioselective, with the silicon
moiety exclusively bonded to the most internal carbon atom of the
1,3-diyne (β-E product), as confirmed by X-ray
crystallography.