Practical synthesis of allylic silanes from allylic esters and carbamates by stereoselective copper-catalyzed allylic substitution reactions

The first copper-catalyzed allylic substitution reactions of allylic acetates and carbamates employing a bis(triorganosilyl)zinc reagent are reported. This novel procedure avoids the use of stoichiometric amounts of copper salts which are usually mandatory with this chemistry. Application of this methodology to standard model substrates substantiates a high diastereoselectivity for the double bond geometry (E: Z) as well as the relative configuration (syn: anti).