Mechanistic investigation on the hydrogenation of imines by[p-(Me2CH)C6H4Me]RuH(NH2CHPhCHPhNSO2C6H4-p-CH3). Experimental support for an ionic pathway.

The need for acidic activation in the stoichiometric hydrogenation of benzyl-[1-phenyl-ethylidene]-amine (6a) or [1-(4-methoxy-phenyl)-ethylidene]-methyl-amine (6b) by Noyori's catalyst [p-Me2CH)C6H4Me]RuH(NH2CHPhCHPhNSO2C6H4-p-CH3) (2) is inconsistent with the proposed concerted mechanism and supports an ionic mechanism.