Abstract Several organosilylcuprates have been prepared and their reactions with acetylenes examined. It has been shown that LiCu [Si (SiMe 3) 3] 2 adds to acetylenes in only one manner, ie with cis addition and the Si (SiMe 3) 3 group in the least hindered cite as shown in the equation below. Similarly the sterically hindered LiCu (SiMePh 2) 2 LiCu [Si (SiMe 3) 2] 2· LiI+ RC CH→ H+, H 2 O→ trans-RHC CHSi (SiMe 3) 3 adds only in this ...
