Deactivation of the Grubbs Carbene Complex [RuCl2(CHPh)(PCy3)2] by Allylic Alcohols

While the (hydroxymethyl)carbene complex [RuCl2(CHCH2OH)(PCy3)2] (2), prepared by metathesis from [RuCl2(CHPh)(PCy3)2] (1) and allyl alcohol, reacts in solution to give the carbonyl derivative [RuCl2(CO)(PCy3)2] (3), in the absence of solvent the methoxycarbene isomer [RuCl2(CHOCH3)(PCy3)2] (4) is formed. The catalytic reaction of 1 with allyl alcohol affords, besides small amounts of ethene and acrolein, predominantly propionaldehyde; with 3-buten-2-ol and catalytic amounts of 1, 3-butanone is obtained exclusively.