Up the Hill: Selective Double-Bond Isomerization of Terminal 1,3-Dienes towards Z-1,3-Dienes or 2Z,4E-Dienes

Against all odds: Two different cobalt catalyst systems led to the selective isomerization of 1,3-dienes. In the case of the [CoBr2(py-imine)]-catalyzed reaction, the Z-1,3-diene was formed in a highly selective manner (see scheme). When the catalyst precursor [CoBr2(dpppMe2)] was applied, a double-bond migration and selective isomerization towards the 2Z,4E-configured 2,4-dienes were observed.