The reduction of 1,3-diketones and β-hydroxyketones with NaBH(4) in aqueous acetonitrile is highly stereoselective in the presence of stoichiometric amounts of bovine or human albumin, giving anti 1,3-diols with d.e. up to 96%. The same reaction, without albumin, gives syn and anti 1,3-diols in approximately 1:1 ratio. The presence of an aromatic carbonyl group is essential for diastereoselecti...

Efficient reduction of monoand disubstituted norbornyl α-diketones with zinc in [bmimBF4]:[H2O] to afford the corresponding acyloins in excellent yields and diastereoselectivities is described. In case of the monosubstituted norbornyl α-diketones, very high regioselectivities ranging from 90:10 to 100:0, in favor of diastereomer possessing endohydroxyl diagonal to endo-substituent were observed.

Thiazolium carbene-catalyzed reactions of 1,2-diketones and 1,2,3-triketones with enones and ynones have been investigated. The diketones gave α,β-double acylation products via unique Breslow intermediates isolable as acid salts, whereas the triketones formed stable adducts with the NHC instead of the coupling products.

Oxidation of 2-hydroxy-9,10-dialkynylanthracenes resulted in highly regioselective dimerization to furnish metastable dearomatized 1,4-diketones rather than stable aromatic diols. The 1,4-diketones were converted to oxahelicenes, which exhibited strong fluorescence both in solution and solid state as well as chiroptical properties.

Thiazolium carbene-catalyzed reaction of aromatic 1,2-diketones with enones in aprotic solvents gave double acylation products in good yields, whereas hydroacylation products formed by Stetter reaction were not detected at all. These results suggested the generation of aroyloxyenamine species from the 1,2-diketones instead of hydroxyenamines (Breslow intermediates).

phenylazo and benzothiazolylazo derivatives of trifluoroacetylacetone andhexafluoroacetylacetone have been synthesized and characterized. analytical and spectral datarevealed the existence of phenylazo derivatives in the intramolecularly hydrogen-bonded ketohydrazoneform while the benzothiazolylazo derivatives in the azo-enol form. the monobasicbidentate coordination of the phenylazo derivative...

the beta0diketone derivatives of nitroimidazole were synthesized from the reaction of magnesium salt of beta-ketoaccids 3 with imidazolide 4. the raction of beta-diketones with hydroxylamine hydrochloride afforded either the isoxazoles or the 5-hydroxyl-2-isoxazolines.

An enzymatic strategy for the preparation of optically pure α-alkyl-α,β-dihydroxyketones is reported. Homo- and cross-coupling reactions of α-diketones catalyzed by acetylacetoin synthase (AAS) produce a set of α-alkyl-α-hydroxy-β-diketones (30-60%, ee 67-90%), which in turn are reduced regio-, diastereo-, and enantioselectively to the corresponding chiral α-alkyl-α,β-dihydroxyketones (60-70%, ...

A group of homologous 2,4-diketones with chain lengths from C13 to C25, derived from fatty acids, is present in human and mammalian tissues and urine. The presence of this lipid class, members of which possess marked chelating properties, adequately accounts for the well-documented antiallergic activity of tissue and urine extracts on isolated smooth muscle preparations and in guinea pigs in vi...

An electron-withdrawing group was introduced to the α-position of chalcones, and the resulting alkylidene diketones showed new reactivities with enals under the catalysis of N-heterocyclic carbenes (NHCs). Selective activation of enals affords enolate equivalents that undergo highly enantioselective intermolecular Diels-Alder reactions with the alkylidene diketones. No products that might have ...