Cobalt-Catalyzed Z to E Geometrical Isomerization of 1,3-Dienes.

An efficient cobalt-catalyzed geometrical isomerization of 1,3-dienes is described. In the combination of a CoCl 2 precatalyst with an amido-diphosphine-oxazoline ligand, the geometrical isomerization of E / Z mixtures of 1,3-dienes proceed in a stereoconvergent manner, affording ( E ) isomers in high stereoselectivity. This facile transformation features a broad substrate scope with good functional group tolerance and could be scaled up to the gram scale smoothly with a catalyst loading of 1 mol %.