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The palladium catalyst for the nucleophilic substitution of benzyl carbonates was improved by using 1,1′-bis(diisopropylphosphino)ferrocene (DiPrPF) as the ligand. The [Pd(η3-C3H5)(cod)]BF4–DiPrPF ...

Effects of the surface-treated A5052 aluminum alloy on the adhesiveness of joining dissimilar materials, such as A5052 aluminum alloy sheet and polyamide resin sheet, was examined to manufacture a multi-material. Various surface treatments for the A5052 sheet were performed. The hot melt adhesive sheet comprising polyamide resin was used as the adhesive. The shear strength of adhered specimens was measured via tensile testing, and the shear strength was made to be the joining strength. Using various surface treatment techniques, oxidation films with different hole sizes and surface roughness were formed on the A5052 aluminum sheets. The joining strength of the surface-treated specimens was the lowest, whereas those joined via anode electrolysis exhibited the highest joining strength. These differences in joining strengths were owing to the anchor effect and chemical interfacial bonding force.

A chemoselective hydrogenation of isoquinoline carbocycles was achieved by using the catalyst prepared from Ru(methallyl)2(cod) and trans-chelate chiral ligand PhTRAP. The unique chemoselectivity achieved in this hydrogenation could be ascribed to the trans-chelation of the chiral ligand. The procedure for preparing the catalyst strongly affects the reproducibility of the carbocycle hydrogenation. Various 5-, 6-, 7-, and 8-substituted isoquinolines were selectively hydrogenated at their carbocycles to afford 5,6,7,8-tetrahydroisoquinolines as major products in high yields with moderate or good enantioselectivities. Some mechanistic studies suggested that the stereogenic center was created during the initial addition of H2 to the aromatic ring in the hydrogenation of 5-substituted isoquinolines. In other words, the stereochemical control was accompanied by the dearomatization.

A wide range of benzyl carbonates reacted with dimethyl phosphonate or diphenylphosphine oxide in the presence of the palladium catalyst, [Pd(η3-allyl)Cl]2–DPEphos, to give dimethyl benzylphosphonates and benzyldiphenylphosphine oxides in high yields. The catalytic phosphonylation was applied to the one-pot synthesis of alkenes from the benzyl esters.

The decarboxylation of benzyl fluorobenzoates has been developed by using the palladium catalyst prepared in situ from Pd(η3-allyl)Cp and bulky monophosphine ligand XPhos. The catalytic reaction afforded a range of fluorinated diarylmethanes in good yields with broad functional-group compatibility. The substrates were readily synthesized by condensation of the corresponding benzoic acid with benzyl alcohol. Therefore, the transformation is formally regarded as a cross-coupling reaction between fluorine-containing benzoic acids and benzyl alcohols.

Transmission used in automobiles is indispensable from the viewpoint of improvement of maximum speed, quietness and fuel consumption even if the power source of automobile is changed from internal combustion engine to electric motor in the future. We are studying a heat treatment process for imparting machinability to the forged material after hot forging used for a transmission of automobiles. In the past, the heat stored in the material after hot forging was merely released into the atmosphere. We succeeded in imparting machinability to the material by cooling while well controlling the heat stored in the forged material after hot forging. In the previous paper [1], we reported the progress of tool wear of this forged material in the high-speed cutting region with the cutting speed of 200 m/min or more in intermittent cutting. In this report, we conducted cutting experiments on the machinability of this developed forged material in the normal cutting speed region with the cutting speed less than 200 m/min. As a result, at the cutting speed V of V=157 m/min or less, it reached the conclusion that the built-up edges frequently occurred and the tool was chipped due to it. From the previous report and the results of this experiment, it was found that the cutting speed V of about V=213 m/min is optimum for cutting these forged materials with cemented carbide.

The dearomative reduction of (hetero)aromatic compounds represents one of straightforward and attractive transformations for the construction of chiral cyclic compounds, which contain important structural motifs in a wide range of scientific disciplines. Stereoselective hydrogenation of carbocyclic arenes requires higher reaction temperature than that of heteroarenes because the benzene ring is highly stabilized with its inherent aromaticity. Considering the kinetic aspects of enantioselective transformations, high reaction temperature is generally unfavorable. To achieve high stereoselectivity, therefore, carefully and precisely designed chiral auxiliary or catalyst is particularly desirable. Herein, we will summarize two distinct approaches for the asymmetric hydrogenation of aromatic carbocycles: (1) through combinational use of chiral auxiliary and heterogeneous catalysis, (2) with chiral homogeneous metal complex as the catalyst.

High enantioselectivity was achieved for the hydrogenation of azaindoles by using the chiral catalyst, which was prepared from [Ru(η(3) -methallyl)2 (cod)] and a trans-chelating bis(phosphine) ligand (PhTRAP). The dearomative reaction exclusively occurred on the five-membered ring, thus giving the corresponding azaindolines with up to 97:3 enantiomer ratio.

A trans-chelating chiral bisphosphine, PhTRAP, allows the ruthenium-catalyzed hydrogenation of various azoles to proceed with high enantioselectivity. The PhTRAP–ruthenium catalyst transformed indo...

The asymmetric hydrogenation of pyrimidines proceeded with high enantioselectivity (up to 99% ee) using an iridium catalyst composed of [IrCl(cod)]2, a ferrocene-containing chiral diphosphine ligand (Josiphos), iodine, and Yb(OTf)3 (cod = 1,5-cyclooctadiene). The chiral catalyst converted various 4-substituted pyrimidines into chiral 1,4,5,6-tetrahydropyrimidines in high yield. The lanthanide triflate is crucial for achieving the high enantioselectivity as well as for activating the heteroarene substrate.

Various unsymmetric indolylmaleimides were synthesized. Their photophysical properties and affinities for amyloid fibrils were evaluated. Some unsymmetric indolylmaleimides have large Stokes shifts of more than 120 nm, fluorescence emission maxima wavelengths of more than 550 nm and different emissions under UV irradiation at 365 nm. From the results of histopathologic methods using stains, 3-(1H-indol-3-yl)-1-methyl-4-phenyl-1H-pyrrole-2,5-dione has high selectivity for amyloid fibrils in senile systemic amyloidosis.

The palladium complex, which is generated in situ from Pd(η 3-C3H5)Cp and tris(4-methoxy-3,5-dimethylphenyl)phosphine, catalyzed the [4+2] cycloaddition of o-(silylmethyl)benzyl carbonates with alkenes. The reaction of the benzyl esters with methyl crotonate gave methyl 3-methyltetralin-2-carboxylate in 84% yield with 2% catalyst loading.

The iridium catalyst [IrCl(cod)]2 -phosphine-I2 (cod=1,5-cyclooctadiene) selectively reduced isoxazolium triflates to isoxazolines or isoxazolidines in the presence of H2 . The iridium-catalyzed hydrogenation proceeded in high-to-good enantioselectivity when an optically active phosphine-oxazoline ligand was used. The 3-substituted 5-arylisoxazolium salts were transformed into 4-isoxazolines with up to 95:5 enantiomeric ratio (e.r.). Chiral cis-isoxazolidines were obtained in up to 89:11 e.r., with no formation of their trans isomers, when the substrates had a primary alkyl substituent at the 5-position. The mechanistic studies indicate that the hydridoiridium(III) species prefers to deliver its hydride to the C5 atom of the isoxazole ring. The hydride attack leads to the formation of the chiral isoxazolidine via a 3-isoxazoline intermediate. Meanwhile, in the selective formation of 4-isoxazolines, hydride attack at the C5 atom may be obstructed by steric hindrance from the 5-aryl substituent.

o-(N-Alkylamino)propiophenones are converted into 4-quinolones in the presence of chlorobenzene, potassium phosphate, morpholine, and nickel(0) catalyst. The reaction proceeds through the nickel-catalyzed formation of β-enaminones from o-(N-alkylamino)propiophenones and morpholine, followed by the intramolecular transamination.

A variety of 3-substituted benzisoxazoles were reduced with hydrogen using the chiral ruthenium catalyst, {RuCl(p-cymene)[(R,R)-(S,S)-PhTRAP]}Cl. The ruthenium-catalyzed hydrogenation proceeded in high yield in the presence of an acylating agent, affording a-substituted o-hydroxybenzylamines with up to 57% ee. In the catalytic transformation, the N–O bond of the benzisoxazole substrate is reductively cleaved by the ruthenium complex under the hydrogenation conditions. The C–N double bond of the resulting imine is saturated stereoselectively through the PhTRAP–ruthenium catalysis. The hydrogenation produces chiral primary amines, which may work as catalytic poisons, however, the amino group of the hydrogenation product is rapidly acylated when the reaction is conducted in the presence of an appropriate acylating agent, such as Boc2O or Cbz-OSu.

In this study, a method for generating ring intensity distribution at a refraction-type lens with an aspheric element was proposed, and the beam shaping optical element was finished using only ultra-precision cutting. The shape of the optical element and its irradiance pattern were determined from numerical calculation based on its geometrical and physical optics. An ultra-precision lathe was employed to fabricate beam shaping optical elements, and acrylic resin was used as the material. The transmittance of an optical element (a rotationally symmetrical body) with an aspheric surface fabricated using a single-crystal diamond tool was over 98%, and its surface roughness was 9.6 nm Ra. The method enabled the formation of a circular melting zone on a piece of stainless steel with a thickness of 300 μm through pulse YAG laser (λ 1:06 μm) processing such that the average radius was 610 μm and the width was 100–200 μm. Circular processing using a ring beam shaping optical element can be realized by single-pulse beam irradiation without beam scanning.

A nickel―phosphine complex was found to be effective as the catalyst for the transformation of alcohols into β-enaminones, which was successively converted into γ-amino alcohols by a conventional reductant. The sequential transformation is equivalent to the carbon―nitrogen bond formation at the γ-position of saturated alcohols.