Hydroalumination of silylacetylenes: A novel and highly stereoselective synthesis of (E)-telluro(silyl)ketene acetals and their applications in Sonogashira cross-coupling reactions

Abstract

The hydroalumination of silylacetylenes with DIBAL-H followed by the addition of n-butyllithium generated in situ the (Z)-β-vinylorganosilane alanates intermediates, which were trapped with butyltellurenyl bromide (C 4H9TeBr), furnishing exclusively the (E)-1-butyltelluro-1- tri(organyl)silyl-2-organyl-1-alkenes in 45-70% yields. These telluro(silyl)ketene acetals were utilized as substrates in Sonogashira cross-coupling Pd-catalyzed reactions, furnishing the (Z)-1,4-diorganyl-2- tri(organyl)silyl-1-buten-3-ynes with total control of regio- and stereochemistry in 62-80% yield. © 2011 Elsevier Ltd. All rights reserved.