In the presence of the co-catalyst NaOH (2.4 mol%), RuC12(PPh& (0.1 mol%) catalyses efficient transfer hydrogenation of both aliphatic and aromatic ketones by propan-2-01 with rates up t o 900 turnovers per hour at 82°C; no hydrogenation occurs in the absence of sodium hydroxide.We have recently developed a mild procedure for the aerobic oxidation of alcohols by the use of the triple catalytic system RuCl( OA~)(PPh~)~-hydroquinone (HQ)-Co(sa1ophen) [eqn. (1); salophen = N, N'-o-phenylenebis(salicylideneaminato)] .1 This reaction involves a multistep electron transfer,lJ the initial step being a dehydrogenation of the alcohol by the ruthenium catalyst. RCH20H + $ 0 2 + RCHO + H20 (1) Conditions: 20°C; cat. R~Cl(oAc)(PPh~)~;cat. HQ; cat. Co(sa1ophen)The ability of ruthenium complexes to dehydrogenate alcohols and deliver the hydrides to a ketone3 or an a$-unsaturated ketone has made them useful as transfer hydrogenation catalysts.4 Most such ruthenium-catalysed transfer hydrogenations of ketones described so far, however, require elevated temperature (150-200 "C).Recently, Cole-Hamilton and coworkers5 reported that base is required in the R~H~(N~)(PPh~)~-catalysed thermal
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.