Four new [RuCl2(perimidine)(p-cymene)] complexes have been prepared and characterized. Upon reaction with 1,1-diphenylprop-2-yn-1-ol they generate catalyst precursors. which perform the cycloisomerization of diallyltosylamide into N-tosyl-alpha-methylenepyrrolidine. (c) 2005 Elsevier B.V. All rights reserved.