No abstract

No abstract

RuH2(PPh3)4 and other hydridoruthenium complexes catalyze selective conversion of aldehydes into esters in high yields. The method is applicable to most aliphatic aldehydes as well as to aromatic aldehydes. The purity of aldehydes is critical for achieving high conversions, since the presence of carboxylic acid completely inhibits the reaction and alcohol and triphenylphosphine reduce the yields of esters. RuH2(PPh3)4 is converted into Ru(CO)3(PPh3)2 through the reaction indicating the occurrence of decarbonylation of aldehyde. A mechanism involving the acyl-H cleavage of aldehyde is proposed to account for the catalysis and formation of compounds accompanying the reaction. The mechanism is compared with an alternative one which comprises of consecutive insertions of two aldehyde molecules into Ru–H bond followed by β-hydrogen abstraction from an alkoxo intermediate formed. Addition of water changes the reaction course to give carboxylato carbonyl complexes Ru(OCOR)2(CO)m(PPh3)2 (m=1 and 2). Cross esterification studies showed the reactivity order of RCHO as R=Et>Me>n-Pr>i-Pr>>Ph.

No abstract

The relationships between the chemical structures and the odor characteristics were examined on a series of highly purified n-hexenols and n-hexenals (14 isomers). The C6-enals and the corresponding alcohols resembled in odor characteristics each other. However, the odor strength of the aldehydes was 100 - 1000 times higher than those of the alcohols. In the principal components analysis, the position of carbon-carbon double-bond in the C6-compounds was closely related to the scores of the first principal component, whereas the functional groups, hydroxy and formyl groups, were related to those of the second principal component except for (Z)-3-hexenol.

No abstract

No abstract

The reaction of cis-Cp*(CO)2HW=SiPh2·Py (1, Py = pyridine) with HCl gave an adduct Cp*(CO)2H2WSiPh2Cl (2). Treatment of 2 with excess LiAlH4 afforded an anionic complex Li[cis-Cp*(CO)2HWSiHPh2] (4), and the same product was obtained by the reaction of 1 with LiAlH4.