Development of a Radical Silylzincation of (Het)Aryl‐Substituted Alkynes and Computational Insights into the Origin of the <i>trans</i>‐Stereoselectivity

Abstract

Abstract Aryl‐ and hetaryl‐substituted acetylenes undergo regio‐ and stereoselective silylzincation by reaction with [(Me 3 Si) 3 Si] 2 Zn in the presence of Et 2 Zn (10–110 mol%) as additive. The distinctive feature of this addition across the C−C triple bond is its trans stereoselectivity. The radical nature of the silylzincation process is supported by diagnostic experiments and DFT calculations, which also corroborate the role played by steric effects to obtain that stereoselectivity. The procedure can be combined in one‐pot with the copper(I)‐mediated electrophilic substitution of the C( sp 2 )−Zn bond, with retention of the double bond geometry. This makes it valuable for the synthesis of stereodefined di‐ and trisubstituted vinylsilanes. magnified image