Nickel-Catalyzed Homocoupling of (Z)-β-Iodoenol Esters: Stereoselective Access to (Z,Z)-Buta-1,3-diene-1,4-diyl Diesters

A straightforward and broad-scope procedure to obtain symmetrically substituted buta-1,3-diene-1,4-diyl diesters, based on the homocoupling of the corresponding ( Z )-β-iodoenol esters, is presented. It involves the use of a catalytic system composed of [NiCl 2 (PPh 3 ) 2 ] (10 mol%), NaI (10 mol%), and excess of Zn dust. The reactions proceed in THF at room temperature with exquisite preservation of the stereochemistry of the C=C bond of the starting iodoolefins, thus leading to the final dienes as the corresponding Z , Z -stereoisomers exclusively.