Substrate-directed regioselective alkene functionalizations of (E)-β,γ-unsaturated carboxylic acids†

A carboxylate-directed regioselective Heck-type alkenylation and alkenylative lactonization of (E)-β,γ-unsaturated carboxylic acids by simply substrate control is reported. (E)- and (Z)-alkenyl bromides reacted to give energetically more favorable palladacyles, allowing access to fully stereocontrolled conjugated 1,3-dienes and alkenyled γ-lactones. Mechanistic studies suggest that excellent regioselectivity may be strongly influenced by the steric factors of reactants involved in the palladacycle intermediates.