Asymmetric Addition of Propargylic Silanes to Aldehydes Catalyzed by Chiral Phosphine-Silver Alkoxide Complex

A catalytic asymmetric addition of propargylic silanes to aldehydes was achieved using a DM-BINAP center dot AgBF4 complex as the chiral pre-catalyst and triethylamine as the base pre-catalyst in the presence of potassium fluoride and methanol. Optically active homoallenylic alcohols and homopropargylic alcohols were obtained in moderate to high combined yields via the in situ generated chiral organosilver species. Allenylated alcohols were formed predominantly with up to 95% ee.