Catalytically Asymmetric Synthesis of 1,3-Bis(silyl)propenes via Copper-Catalyzed Double Proto-Silylations of Polar Enynes

A copper-catalyzed double proto-silylations of electron-deficient conjugated enynes to synthesize functional bis­(silyl)­propenes was developed. Under mild reaction conditions, the silylboronate PhMe₂Si-Bpin reacts with the enynes via cascade proto-silylations and yields the corresponding <i>Z</i>-specific bis­(silyl)­propene products in up to 98% yield and 95% ee. In addition, the enantioselective synthesis of these compounds was also achieved by using enantiopure pyridine-oxazoline-based ligand