A Stille-type reaction that employs alkynes as pseudohalides provides access to the catalytic chemistry of palladium-carbon sigma-bonds starting from pi-systems. The synthesis of a variety of tri- and tetra-substituted olefins by addition of sp(2)- and sp-hybridized stannanes across mono- and diester alkynes was accomplished with complete regioselectivity and high stereoselectivity. The reaction is proposed to proceed via a bimetallic mechanism where the Lewis acidic Au(I) activates the alkyne toward oxidative addition across Pd(0).