Atom-economic, regiodivergent, and stereoselective coupling of imidazole derivatives with terminal allenes.

New Rh- and Pd-catalyzed regiodivergent and stereoselective intermolecular coupling reactions of imidazole derivatives with mono-substituted allenes are herein reported. Using a Rh(I)/Josiphos system, perfect regioselectivities and high enantiomeric excess were obtained, while a Pd(II)/dppf system gave linear products with high regioselectivities and high E/Z selectivities. This method permits the atom economic synthesis of valuable branched and linear allylic imidazole derivatives.