Al(III)-Promoted Formation of All-Carbon Quaternary Centers from Aliphatic Tertiary Chlorides and Alkynyl Silanes.

Despite the accessibility of numerous alkynes through coupling or substitution reactions, the synthesis of trialkyl-substituted alkynes is still a major challenge. Within this context, we reexplored the electrophilic alkynyl substitution between tertiary aliphatic chlorides and silylated alkynes. We were able to demonstrate that this approach is significantly more general than originally demonstrated by Capozzi and even tolerates several functional groups. Furthermore, we report diastereoselective reactions which in some instances gave excellent diastereoselectivity (dr >95:5).