The decarbonylation of saturated aldehydes by the ruthenium–diethylphenylphosphine complex, tri-µ-chloro-hexakis(diethylphenylphosphine)diruthenium chloride

Abstract

The complex [Ru,CI,( Et,PhP),] +CI-abstracts a carbonyl group from saturated aldehydes to give RuCI,(CO) (Et,PhP),.With acetaldehyde the other product is methane. With propanol and butanal the hydrocarbons formed comprise the alkane and the alkene derived from the alkyl chain : the alcohol corresponding to the aldehyde is also observed as a reaction product. This system differs from the decarbonylation of aldehydes by RhCI( Ph,P), in which, under similar conditions, the hydrocarbon formed is predominantly the alkane. The difference is further illustrated by the reactions of the ruthenium and rhodium complexes with the deuteriated aldehydes C,H&DO and CD,CH,CHO.Whereas the rhodium complex leads to C,H5D and CD,CH, respectively, supporting published evidence of an intramolecular transfer (with respect to one molecule of aldehyde) of the aldehydic hydrogen to the alkyl group, the ruthenium system gives rise to a variety of deuteriated hydrocarbons showing labilisation of both a-and P-hydrogen atoms. No evidence for free-radical participation has been obtained for the ruthenium system, for which possible reaction mechanisms are discussed : participation of a 3 ~ketyl system provides an attractive rationalisation of the exchange observations.WE have previously reported the decarbonylation of several papers have been published 3-9 on the decarbonylsaturated aldehydes by the known complex ation of aldehydes by RhC1(Ph3P)3.10~6 This paper [Ru2C13(Et2PhP),]+C1-. During the course of our work describes the extension of the work on the ruthenium

Catalytic decarbonylation of aldehydes

“…In both the and 13C NMR spectra, the methylene peaks broadened and decoalesced into two separate peaks without affecting the chemical shifts associated with the other two carbon atoms. Similar behavior was also reported for the 1-propylcyclobutyl cation (5). From the new, very low temperature observations, Sorensen and Kirchen rightly ruled out the previously suggested3-4 equilibrating cyclopropylcarbinyl-1-methylcyclobutyl structures (2 ^3).…”

Acid‐, Water‐ and High‐Temperature‐Stable Ruthenium Complexes for the Total Catalytic Deoxygenation of Glycerol to Propane

“…The carbonyl complexes [(L)Ru(CO)(H 2 O) 2 ](OTf) 2 are formed in situ through decarbonylation of the actual hydrogenation substrate hexanal. The (catalytic) decarbonylation of aldehydes at ruthenium centers has multiple precedents in the literature 51–54. The color change back to purple after complete conversion of the substrate to 1‐hexanol and hexanes at temperatures> 200 °C then points to a thermal loss of CO(g) from the complexes [(L)Ru(CO)(H 2 O) 2 ](OTf) 2 regenerating the triaqua complexes [(L)Ru(OH 2 ) 3 ](OTf) 2 ( 3 or 4 ) in the aqueous acidic reaction medium.…”

“…The (catalytic) decarbonylation of aldehydes at ruthenium centers has multiple precedents in the literature. [51][52][53][54]…”

Rhodium-Catalyzed Hydroformylation of 4-Vinylpyridine: 4-Ethylpyridine Formation via an Unusual Cleavage of the Rh−C Bond by the Enolic Form of the Oxo Product

“…Hypothesis b can be excluded too on the basis of deuterioformylation experiments. According to the mechanism proposed for decarbonylation, a dideuterated species would be expected, but not a monodeuterated one as found experimentally.…”