Reaction of sulphoximides with diazomalonate in the presence of Cu-salt : A new synthesis and stereochemistry of optically active oxosulphonium ylides

Sulphoximides (Ia–Ie) were found to react with dimethyl diazomalonate (DDM) in the presence of a catalytic amount of Cu-salts affording the corresponding oxosulphonium ylides in moderate yields. The reaction did not proceed at all under irradiation of UV light. (?)-Methylphenyloxosulphonium bis(methoxycarbonyl)-methylide ((?)-IIb) was obtained from (+)-(S)-methylphenylsulphoximide ((+)-(S)-Ib) together with (?)-(S)-methyl phenyl sulphoxide ((?)-(S)-IIIb) by this reaction. Hydrolysis of (?)-IIb gave (+)-methylphenyloxosulphonium methoxycarbonylmethylide ((+)-IIf) which was converted to (?)-(S)-IIIb upon treatment with dibenzoylethylene. Stereochemical cycle starting from (+)-(S)-Ib to (?)-(S)-IIIb was established and the absolute configurations of both ylides, (?)-IIb and (+)-IIf were assigned as (R)-configuration. The stereochemical courses, namely from (+)-(S)-Ib or (?)-(S)-IIIb to (?)-(R)-IIb or (+)-(R)-IIf to (?)-(S)-IIIb were determined as retention processes. The optical purities of the oxosulphonium ylides obtained from both reactions, (+)-(S)-Ib→(?)-(R)-IIb and (?)-(S)-IIIb→(?)-(R)-IIb, were almost equal. These results indicate that the mechanism of the reaction of sulphoximides with carbenes (or carbenoids) involves the initial formation of the sulphoxides which react subsequently with carbenes to afford the final products.     

Statistical analysis of fluctuations of froth pressure on perforated plates without downcomers

Statistical properties of fluctuations of pressure drop across the gas–liquid dispersions on the tray were analyzed using a 215 mm dia. three plates column with different trays. Hydrodynamic regimes of the froth were characterized in terms of the statistical properties evaluated. It was proved that the on-line estimation of the flow behavior of the froth was possible on the basis of the pattern recognition of the power spectral density function of the pressure fluctuations. The time-domain stochastic models for fluctuations of the pressure drop were identified so as to be available for its forecast and simulation.     

Image reconstruction by using the propagation law of mutual intensity

An imaging method for partially coherent objects is proposed by the aid of the propagation law of mutual intensity, and it can be reduced to principles used in holography and radio astronomy if the coherence reaches the both extremes, i.e., perfect coherence and complete incoherence, respectively.     

Arylmagnesiation of alkynes catalyzed cooperatively by iron and copper complexes

Iron and copper complexes cooperatively catalyzed the arylmagnesiation of unfunctionalized alkynes including dialkylacetylenes, where the presence of both iron and copper catalysts is essential for high yields of 2-aryl-1-alkenylmagnesium bromides.     

Chloro­[N′,N′‐diethyl‐N,N‐bis(2‐pyri­dyl­methyl)­ethyl­enedi­amine‐κ4N]copper(II) perchlorate

The title mononuclear copper(II) complex, [CuCl(C₁₈H₂₆N₄)]ClO₄, shows a square‐pyramidal coordination with the diethyl­amino N atom at the apical position. Large anisotropies in the displacement parameters of the non‐H atoms of the ligand seem to be due to rotational disorder of the ClO₄^? anion.