Efficient preparation of 2-azulenylboronate and Miyaura-Suzuki cross-coupling reaction with aryl bromides for easy access to poly(2-azulenyl)benzenes

This paper describes an efficient preparation of 2-azulenylboronate (6) starting from 2-iodoazulene by halogen-metal exchange reaction using n-BuLi and subsequent quenching with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. The boronate 6 has been found to undergo Pd-catalyzed Miyaura-Suzuki cross-coupling reaction with a range of aryl bromides including aromatic poly bromides utilizing Pd₂(dba)₃-P(t-Bu)₃ as a catalyst and establishes a strategy to produce novel poly(2-azulenyl)benzenes, some of which are found to be insoluble in common organic solvents, however. The redox behavior of 2-arylazulenes and poly(2-azulenyl)benzenes was examined by cyclic voltammetry (CV) and compared with those of 6-azulenylbenzene derivatives reported previously.     

Total synthesis of RK-397

An enantioselective synthesis of the polyene macrolide RK-397 is described. The use of the same eight-carbon building block twice for the construction of the polyol chain allowed for a highly convergent synthesis. The synthesis highlights stereoselective vinylogous aldol addition using a chiral bisphosphoramide as well as a sequential palladium-catalyzed cross-coupling reaction for the preparation of key fragments.     

Flexible transparent fluorinated nanohybrid with innovative heat‐resistance property—new technology proposal for fabrication of transparent materials using “crystalline” polymer

A new technology for the production of transparent material, using a “crystalline” polymer, is proposed in this study. In addition, a heat‐resistant transparent flexible plastic film with a high hydrophobic surface and a thermal decomposition temperature near 400 °C was created. Partially fluorinated crystalline polymer with switchboard‐type lamellae results high transparency as a consequence of the formation of a high‐density amorphous structure based on high‐temperature drawing just below the melting point at 250 °C. Melt‐compounding with montmorillonite modified by the long‐chain quaternary phosphonium with high coverage induces formation of a nanohybrid that retains transparency and also results in an increase in the thermal degradation temperature by over 50 °C. Through this technology, which results in heat‐resistance, transparency, and flexibility, the nano‐micro‐millimeter structures of solid‐state polymers are hierarchically controlled, which enables the creation of new materials. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1674–1690     

Ablation process of silica glass induced by laser plasma soft X-ray irradiation

Silica glass can be machined by irradiation with laser plasma soft X-rays on nano- and micrometer scale. We have investigated the ablation process of silica glass induced by laser plasma soft X-ray irradiation. We observed ionic and neutral species emitted from silica surfaces after irradiation. Dominant ions and neutrals are O⁺ and Si⁺ ions and Si, O, SiO and Si₂ neutrals, respectively. The ions have kinetic energies of 13 and 25 eV, which are much higher than those of particles emitted by evaporation. The energy of laser plasma soft X-rays absorbed to silica glass at a fluence of 1.4 J/cm² is estimated to be 380 kJ/cm³, which is higher than the binding energy of SiO₂ of 76 kJ/cm³. These results suggest that the most of the bonds in silica glass are broken by absorption of laser plasma soft X-rays, that several percent of the atoms are ionized, and that neutral atoms are emitted together with repulsive ions. The process possibly enables us to fabricate nano structures.