Synthesis of bis‐ N ‐alkyl imidazolium salts and their palladium(0)(NHC)(η 2 ‐MA) 2 complexes

New N ‐Alkyl‐substituted imidazolium salts as well as a series of their corresponding [Pd(NHC)(MA) 2 ] complexes have been obtained by three routes in good yield. The previously reported synthesis for the analogous N ‐aryl substituted [Pd(NHC)(MA) 2 ] complexes has been improved. The N ‐alkyl‐substituted [Pd(NHC)(MA) 2 ] complexes are thermally more labile than their N ‐aryl counterparts. Catalytic transfer semi‐hydrogenation of phenylpropyne resulted in good to excellent chemo‐ and stereo‐ selectivity conversion into ( Z )‐phenylpropene. The size of the alkyl substituents correlates with the rate of hydrogenation in the sense that more bulky substituents give rise to faster transfer hydrogenation rates. Copyright © 2012 John Wiley & Sons, Ltd.