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By using a phosphine oxide-catalyzed enantioselective double aldol reaction, we achieved the concise construction of C2 -symmetric 1,9-diarylnonanoids, enabling the synthesis of (-)-ericanone from p-hydroxybenzaldehyde in 6 steps with 65 % overall yield. The enantioselective double aldol reaction is useful for establishing C2 -symmetric 1,9-diaryl-3,7-dihydroxy-5-nonanones with a single operation. Furthermore, the use of o-nosyl-protected p-hydroxybenzaldehyde and a 4,4'-disubstituted BINAP dioxide catalyst dramatically improved the reactivity and selectivity in the double aldol reaction, enabling the total synthesis of (-)-ericanone with high yield and with excellent enantiopurity.

2,3-Dihydro-4-pyranones were synthesized stereoselectively using a chiral phosphine oxide as the catalyst. The phosphine oxide sequentially activated silicon tetrachloride and promoted the double aldol reaction of 4-methoxy-3-buten-2-one with aldehydes. Subsequent stereoselective cyclization afforded the corresponding highly functionalized 2,3-dihydro-4-pyranones bearing three contiguous chiral centers in good yields and with high diastereo- and enantioselectivities.

Tsai-type icosahedral quasicrystals (i-QCs) are present in numerous alloy systems. Among them, the icosahedral Ag–In–Yb quasicrystal (i-Ag–In–Yb) is regarded as a prototype for studying various features of QCs, such as crystalline structure and physical properties, due to its good average structural order, good stability both in air and in ultra-high vacuum, amenability to growth of large single grains, and lack of elements with high vapor pressure or toxicity. Here we present a review on recent studies of i-Ag–In–Yb, including studies on bulk structure, crystal growth, physical properties, surface structure and thin film growth on quasicrystalline surface. We believe the results will encourage studies on other QCs.

Diene catalysts with a twist: The title C2 -symmetric tetralin-fused 1,3-butadiene derivative is atropisomeric and can be resolved into the two helical enantiomers. The optically pure compound showed excellent enantioselectivity as well as unusually high catalytic activity as a chiral Lewis basic organocatalyst in the asymmetric allylation of various aldehydes with β-substituted allyltrichlorosilanes.

The reaction of alkyl methyl ketones with aromatic aldehydes under the conditions shown affords dihydroxyketones with high stereoselectivity.

New copper catalysts supported on commercially available chelate resins possessing iminodiacetic acid (DIAION CR11) and polyamine moieties (DIAION CR20) are developed.

The Prins cyclization of hydroxy-substituted allenylsilanes such as (I) with carbonyl compounds is efficiently achieved with TmsOTf to yield 2,3-dihydrofuran structures.

The title compounds are characterized by powder XRD, magnetic susceptibility, specific heat, and electrical resistivity measurements.

The compounds M[Al(NH2)4]x (M: K, Mg, Ca; x = 1, 2) along with previously reported LiAl(NH2)4 and NaAl(NH2)4 are prepared by ball milling under liquid NH3 and their structural and gas desorption properties are characterized by synchrotron powder XRD, FTIR and NMR spectroscopy, and thermogravimetry coupled with mass spectroscopy.

On an oxidative dimerization in dichloromethane containing diisopropylamine, methyl 1-ethoxycarbonyl2,5,6,11-tetrahydro-3-oxo-3H-indolizino[8,7-b]indole-5-carboxylate gave a trichotomine derivative bearing ethoxycarbonyl groups on C1 and C1′. In the presence of triethylamine, the initially formed trichotomine derivative changed to a blue compound, which had the skeleton of the trichotomine derivative and a =CH–CH= group. The X-ray crystallographic analysis of the trichotomine derivative showed the torsion around the central C–C double bond, and the dihedral angle of the adjacent two five-membered rings was 30.0°. This torsion is due to the steric interactions between the ethoxycarbonyl groups and the amido carbonyl groups, and might explain the difference of the λmax between the trichotomine derivative (690 nm) and the blue compound (633 nm).

Two bioactive novel triterpene glycosides named hovenidulciosides A1 and A2 have been isolated from a Chinese natural medicine, Hoveniae Semen Seu Fructus, the seeds and fruit of Hovenia dulcis Thunb. (Rhamnaceae). The absolute stereostructures of hovenidulciosides A1 and A2 with a migrated 16,17-seco-dammarane skeleton have been determined on the basis of chemical and physicochemical evidence which included the X-ray crystallographic analysis of the p-bromobenzoate of their common aglycone, hovenidulcigenin A. Hovenidulciosides A1 and A2 exhibited inhibitory activity on the histamine release from rat mast cells induced by compound 48/80 or calcium ionophore A-23187.

Two new antiallergic cyanoglycosides named rhodiocyanosides A and B were isolated from the Chinese natural medicine "Si Lie Hong Jing Tian" (Shiretsukoukeiten in Japanese), the underground part of Rhodiola quadrifida (Pall.) Fisch. et Mey., together with two new glycosides, octyl alpha-L-arabinopyranosyl(1-6)-beta-D-glucopyranoside and gossypetin 7-O-beta-D-glucopyranosyl(1-3)-alpha-L-rhamnopyranoside. Their chemical structures were determined on the basis of chemical and physicochemical evidence. Rhodiocyanosides A and B exhibited inhibitory activity on the histamine release from rat peritoneal exudate cells sensitized with anti-DNP IgE. In addition, rhodiocyanoside A was found to inhibit the PCA reaction in rats.

RuO 2 - Re 2 O 3 /Ti (Ru: Re 7:3) electrodes prepared from the thermal decomposition of RuCl 3 and Re Cl 3 were much more porous than conventional RuO 2 /Ti electrodes. Porosities of the RuO 2 - Re 2 O 3 /Ti electrodes depended on the ionic radii of the rare earth ions. Rare earth ions added to electrodes to prepare the RuO 2 - Re 2 O 3 /Ti electrodes were completely dissolved in the acid solution. After dissolution of the rare earth ions, the voltammetric charges of the resulting RuO 2 /Ti electrodes were still large. Rare earth chlorides were effective as pore initiators in preparing porous RuO 2 /Ti electrodes, and were recovered after the preparation as catalysts.

Three new organic hosts are described that contain a tetraaza[14]annulene core to which two crown ether voids are attached. These hosts include a free base tetraaza[14]annulene and/or its complexes with benzo-15-crown-5 rings. The crown tetraaza[14]annulene is synthesized from tetraaza[14]annulene and 4′-chloroformylbenzo-15-crown-5. Its nickel(II) and copper(II) complexes are prepared in a similar manner as above. In solution the compounds do not tend to form aggregates. However, aggregation is affected by the presence of alkali-metal salts, which coordinate to the crowns. Li+ and Na+ cations with diameters that match the diameters of the crown ether rings form 1:2 host-guest complexes. Complexes with 2:2 host-guest stoichiometry are formed when the diameters of K+ and Cs+ cations exceed that of the crown ether rings. Nevertheless, it is weak for the present macrocycle and its complexes to be inclined to form dimers owing to the steric hindrance of the substituent groups and owing to restraining the rotation of the carbonyl bond connecting the crown ether group.

The cultured suspension cells of Marchantia polymorpha hydrolyzed cyclohexanone enol acetates with 2-alkyl groups to afford optically active ketones. The stereoselectivity of the protonation of the enol intermediate was reversed when the chain length of alkyl substituents was increased.

Porous RuO2/Ti electrodes were prepared from RuO2La2O3/Ti (Ru:La=7:3) electrodes with the complete dissolution of lanthanum ions in H2SO4. Although the voltammetric charge of RuO2La2O3/Ti (Ru:La=7:3) electrodes partially decreased as lanthanum ions were dissolved, charges of the resulting porous RuO2/Ti electrodes were still about 20 times as large as those of the conventional RuO2/Ti electrodes prepared by the thermal decomposition method. The novel route through RuO2La2O3/Ti electrodes was significant for the preparation of porous RuO2/Ti electrodes.

A reductase, which catalyses the NADH-dependent reduction of the C=C bond adjacent to the carbonyl group, was characterized with regard to the stereochemistry of the hydrogen transfer into the substrate. The reductase was isolated from Euglena gracilis Z and was found to reduce stereospecifically the C=C bond of carvone by anti-addition of hydrogen from the si face at α-position to the carbonyl group and the re face at β-position. The hydrogen atoms participating in the enzymatic reduction at α- and β-position to the carbonyl group originate from the medium and the pro-4R hydrogen of NADH, respectively.

Two esterases participating in the asymmetric hydrolysis of α-alkylated enol acetates to α-chiral ketones were isolated from the cultured cells of Marchantia polymorpha . These two esterases had opposite enantioselectivities and both of them reversed the stereoselectivity of protonation into the enol intermediate in the hydrolysis when the chain length and the bulkiness of α-substituents were increased.

A novel 74 kDa enone reductase which catalyzes the reduction of the exocyclic C–C double bond of enones was isolated from cultured cells of Nicotiana tabacum. The reductase was found to catalyze the enantiofacially selective reduction of the C–C double bond of 2-alkylidenecyclohexanone to give optically active (S)-2-alkylcyclohexanone.

Crystal structure of a series of mixed-metal oxides, T2Mo3O8 (T=Mg, Co, Zn and Mn; P63mc; a=5.7628(1) A, c=9.8770(3) A for Mg2Mo3O8; a=5.7693(3) A, c=9.9070(7) A for Co2Mo3O8; a=5.7835(2) A, c=9.8996(5) A for Zn2Mo3O8; a=5.8003(2) A, c=10.2425(5) A for Mn2Mo3O8) was investigated by X-ray diffraction on single crystals. Structural analysis, magnetization measurements, X-ray photoemission spectroscopy and cyclic voltammetry showed that the Mn ions at the tetrahedral and octahedral sites in Mn2Mo3O8 adopt different valences of +2 and 2+δ (δ>0), respectively. The formal valence of the Mo3 in Mn2Mo3O8 is 12−δ to retain electric neutrality of the compound. In contrast, the T ions and Mo3 in T2Mo3O8 (T=Mg, Co and Zn) adopt the valences of +2 and +12, respectively.

Quadruple perovskites Ba{sub 4}LnRu{sub 3}O{sub 12} (Ln=La, Nd, Sm-Gd, Dy-Lu) were prepared and their magnetic properties were investigated. They adopt the 12L-perovskite-type structure consisting of Ru{sub 3}O{sub 12} trimers and LnO{sub 6} octahedra. All of these compounds show an antiferromagnetic transition at 2.5-30 K. For Ba{sub 4}NdRu{sub 3}O{sub 12}, ferrimagnetic ordering has been observed at 11.5 K. The observed magnetic transition is due to the magnetic behavior of the Ru{sup 4.33+}{sub 3}O{sub 12} trimer with S=1/2 . Magnetic properties of Ba{sub 4}LnRu{sub 3}O{sub 12} were compared with those of triple perovskites Ba{sub 3}LnRu{sub 2}O{sub 9} and double perovskites Ba{sub 2}LnRuO{sub 6}. - Graphical abstract: Quadruple perovskites Ba{sub 4}LnRu{sub 3}O{sub 12} (Ln=La, Nd, Sm-Gd, Dy-Lu) were prepared. They adopt the 12L-perovskite-type structure consisting of Ru{sub 3}O{sub 12} trimers and LnO{sub 6} octahedra. All of these compounds show an antiferromagnetic transition at 2.5-30 K. For Ba{sub 4}NdRu{sub 3}O{sub 12}, ferrimagnetic ordering has been observed at 11.5 K. The observed magnetic transition is due to the magnetic behavior of the Ru{sup 4.33+}{sub 3}O{sub 12} trimer with S=1/2 . Magnetic properties of Ba{sub 4}LnRu{sub 3}O{sub 12} were compared with those of triple perovskites Ba{sub 3}LnRu{sub 2}O{sub 9} and double perovskites Ba{sub 2}LnRuO{sub 6}.

An all-inorganic complex, [Mn2{(VO3)5}2]6– (1), was synthesized, and the structure determination reveals a dinuclear manganese complex coordinated by two cyclic pentavanadate ligands. The cyclic pentavanadate units sandwich the edge-sharing octahedral dimanganese core through coordination of the oxido group of the pentavanadate. A dinuclear cobalt complex with a cyclic decavanadate, [Co2(OH2)2(VO3)10]6– (2), was also synthesized. The structure analysis reveals a dinuclear cobalt complex with a macrocyclic decavanadate, which is composed of 10 VO4 units joined by the vertex sharings. The CoO6 octahedrons are edge-shared, with each cobalt octahedron coordinated to five oxido groups from the decavanadate. The remaining site is occupied by water. The coordinated water molecules are supported with hydrogen bonds in two directions. Complex 2 in acetonitrile shows no reactivity with dioxygen even at low temperature, and the cyclic voltammogram of 2 shows no redox chemistry in acetonitrile. Complex 2 exhibits chromism by water exposure both in the solid state and in acetonitrile. Complex 2 is green–yellow in color, and the addition of water causes the complex to turn brown. After heating the sample, it returns to its original color in a reversible manner. The EXAFS data in acetonitrile is also reported and is consistent with the solid-state structure. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

New quadruple perovskite oxides Ba4LnIr3O12 (Ln=lanthanides) were prepared and their magnetic properties were investigated. They crystallize in the monoclinic 12L-perovskite-type structure with space group C2/m. The Ir3O12 trimers and LnO6 octahedra are alternately linked by corner-sharing and form the perovskite-type structure with 12 layers. The Ln and Ir ions are both in the tetravalent state for Ln=Ce, Pr, and Tb compounds ( Ba 4 L n 4 + Ir 3 4 + O 12 ) , and for other compounds (Ln=La, Nd, Sm–Gd, Dy–Lu), Ln ions are in the trivalent state and the mean oxidation state of Ir ions is + 4.33 ( Ba 4 L n 3 + Ir 3 4 + . 33 O 12 ) . An antiferromagnetic transition has been observed for Ln=Ce, Pr, and Tb compounds at 10.5, 35, and 16 K, respectively, while the other compounds are paramagnetic down to 1.8 K.

Chiral phosphine oxide successfully catalyzed the direct aldol-type reactions of cyclohexanone derivatives and benzaldehyde derivatives in high stereoselectivities. The reaction mechanism involves the in situ formation of trichlorosilyl enol ethers. The present reaction could be extended to the cross-aldol reactions between two aldehydes.

The enantioselective aldol reaction of a silyl ketene acetal was promoted by chiral phosphine oxide-activated tetrachlorosilane to afford the corresponding adduct in high yield with moderate enantioselectivity.

An enantioselective total synthesis of pseudodehydrothyrsiferol has been accomplished. The synthetic sequence highlights formation of the highly strained tetrahydropyran C-ring by a Mitsunobu-type ...

Chelated tethering ligands were confined on a Au( 11) substrate, and the confinement of the ligands was confirmed by X-ray photoelectron spectroscopy (XPS). Palladium was anchored to the ligands to construct heterogeneous {Pd}-L-Au(11) catalysts (L = ligand). A {Pd}-Au(11) catalyst was also prepared by adsorbing the Pd complex directly on the Au(lll) substrate without a tethering ligand. Both types of catalysts were used in the Mizoroki-Heck reaction to evaluate their catalytic activities. The tether-ligated Pd catalyst (Pd}-L-Au(111) activity decreased with recycling, whereas the {Pd}-Au(111) catalyst was quite stable upon reuse. The surfaces of both catalyst types were evaluated using XPS to determine the presence of tethering ligands and/or Pd on the Au(111). The ligands of the tether-ligated Pd catalysts could not be detected on the Au(111) surface after the Mizoroki-Heck reaction, which suggests weak bonding of the S-Au by which the ligand is bound to the Au(111) substrate.

Synthesis, crystal structures, and magnetic properties of new quaternary oxides Ba4LnRu3O12 (Ln = lanthanides) were investigated. From the powder X-ray and neutron diffraction measurements, it is found that they adopt the 12L-perovskite-type structures consisting of Ru3O12 trimers and LnO6 octahedra. The Ba4LnRu3O12 for Ln = Tb−Lu have a hexagonal unit cell with the space group R3m, while those for Ln = La−Nd, Sm−Gd have a monoclinically distorted cell with C2/m. Only for Ln = Ce, Pr, and Tb compounds, the Ln ions are in the tetravalent state. The magnetic properties of these three compounds were investigated. For Ba4CeRu3O12, no magnetic transition was observed down to 0.5 K. The Ba4PrRu3O12 and Ba4TbRu3O12 show an antiferromagnetic transition at 2.4 and 24 K, respectively. The magnetic structure for Ba4TbRu3O12 was determined by powder neutron diffraction measurements at low temperatures, which indicates the long-range antiferromagnetic ordering.

Biodegradation pathways of taxol in cultured cells of Synechocystis sp. PCC 6803, Synechococcus sp. PCC 7942, Marchantia polymorpha, Nicotiana tabacum, and Glycine max were investigated using a water-soluble taxol derivative, 7-acetyltaxol-2"-yl glucoside, as the substrate. Although cyanobacteria, Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7942, and a lower plant, M. polymorpha, catalyzed the epimerization at 7-position of taxol skeleton, no epimerization occurred with higher plants, N. tabacum and G. max. On the other hand, Synechocystis sp. PCC 6803, Synechococcus sp. PCC 7942, M. polymorpha, and N. tabacum catalyzed hydrolysis at 13-position of taxol to give baccatin III and 10-deacetyl baccatin III. Both cyanobacteria cells also deacetylated 7-epi-baccatin III at its 10-position. M. polymorpha and G. max deacetylated at 10-position of taxol.

Asymmetric transformation of enones was investigated with cultured cells of Synechococcus sp. PCC 7942 (a cyanobacterium). The cells reduced both the endocyclic C–C double bond of s-trans enones an...

Synechococcus sp. PCC 7942, a cyanobacterium, reduced both the endocyclic C–C double bond of s- trans enones and the exocyclic C–C double bond of s- cis enones with high enantioselectivity to afford the corresponding ( S )-ketones under illumination.