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Reductions of ( Z )-C 6 H 5 CH CXC( O)CH 3 (X = Cl, Br) mediated by Saccharomyces cerevisiae , Candida albicans , Rhodotorula glutinis , Geotrichum candidum and Micrococcus luteus gave the corresponding halohydrins through consecutive reduction reactions of C C and C O bonds. In general, the reactions performed in the biphasic system water/[(bmim)PF 6 ] gave better diastereoselectivity and enantioselectivity than in pure water.

Dehydration of 4-hydroxy-2-butanone (HB) to 3-buten-2-one (MVK) was investigated. Anatase-TiO 2 exhibited excellent activity for the dehydration of HB with 98.8 mol% MVK yield. The highest activity was obtained at 160 °C, and deactivation was rarely observed over anatase-TiO 2 . HB decomposes into propanone above 240 °C, and the MVK selectivity decreases with increasing temperature. High acidity of catalysts causes deactivation because of strong interaction between MVK and acid sites that induces polymerization. Weak acid sites are efficient for the dehydration of HB to MVK.

The high catalytic activity and selectivity of zeolites HBeta and HZSM-12 were found in the synthesis of (E)-4-phenyl-3-buten-2-one by the reaction of styrene with acetic anhydride.

The synthesis of 1,1,1-trichloro-4,4-diethoxy-3-buten-2-one and three trichloroacetylacetate derivatives from the acylation reaction of respective trialkyl orthoacetates and orthopropionates with trichloroacetyl chloride in good yields, is reported. The title compounds were used for the regiospecific preparation of two isoxazoles and five pyrazoles in the cyclocondensation with hydroxylamine and hydrazines, respectively. The transformation of the trichloromethyl group under mild conditions into carboxylic groups is also described.

The Michael addition of β-keto esters to 3-buten-2-one (methyl vinyl ketone, MVK) in the presence of a pentacoordinate organosilicate was investigated. Ethyl 2-oxo-1-cyclohexanecarboxylate reacted with MVK in the presence of potassium bis(1,2-benzenediolato)phenylsilicate to furnish ethyl 2-oxo-1-(3-oxo-1-butyl)-1-cyclohexanecarboxylate in 96% isolated yield. Ethyl 2-oxo-1-cyclopentanecarboxylate, ethyl 2-oxo-1-cyclooctanecarboxylate, ethyl 2-methyl-3-oxobutanoate, and ethyl 2-ethyl-3-oxobutanoate also reacted with MVK in the presence of potassium bis(1,2-benzenediolato)phenylsilicate to produce the corresponding 1,4-adduct in moderate to good yields. In these reactions, the silicate might work as both a Lewis acid catalyst and a Bronsted base catalyst at the same time.

On 1n,π*-excitation, the title compound 2 undergoes a photoinduced intramolecular [4 + 2]-cycloaddition affording the tetracyclic enol ether 3 as the only product in 79% yield. The assigned structure of 3 was confirmed by its conversion to the p-nitrobenzoate 6 whose structure was determined by X-ray analysis.