Synthesis and electronic structure of highly electron-accepting radiaannulene and its reduced species

Highly electron-accepting radiaannulene (1) was synthesized. CV measurements revealed a high electron accepting ability and strong electronic coupling in the anionic species. Spectroelectrochemical analysis revealed a very low-energy absorption band in the spectra of 1⁻ and 1²⁻.     

Visible-light-mediated addition of α-aminoalkyl radicals generated from α-silylamines to α,β-unsaturated carbonyl compounds

Visible-light-mediated addition of α-aminoalkyl radicals generated from α-silylamines to α,β-unsaturated carbonyl compounds using a photoredox catalyst is developed. We also succeeded in the isolation of a silyl enol ether as a primary product of the photochemical reaction.     

Chemical liquid deposition of aromatic poly(azomethine)s by spontaneous on-site polycondensation in aqueous solution

Colored Schiff-base π-conjugated polymer thin films from different combinations of aromatic amines and aldehydes have been prepared. The polymer films spontaneously form under ambient conditions by simple immersion of graphite substrates in an aqueous solution containing the monomer units. Chemical liquid deposition is achieved by delicate control of solution pH, which allows surface selective polymerization and deposition but inhibits reaction in the aqueous phase.     

A bifunctional catalyst for carbon dioxide fixation: cooperative double activation of epoxides for the synthesis of cyclic carbonates

We have developed a very active bifunctional porphyrin catalyst showing a high turnover number (TON = 103,000) for the synthesis of cyclic carbonates from CO(2) and epoxides under solvent-free conditions.     

Efficient preparation of Fmoc-aminoacyl-N-ethylcysteine unit, a key device for the synthesis of peptide thioesters

The synthesis of Fmoc-aminoacyl-N-ethyl-S-triphenylmethylcysteine, an N- to S-acyl migratory device for the preparation of peptide thioesters by Fmoc-SPPS (solid-phase peptide synthesis) is described. Condensation of Fmoc-aminoacyl pentafluorophenyl ester and N-ethyl-S-triphenylmethylcysteine was efficiently performed in the presence of HOOBt (3-hydroxy-3,4-dihydro-4-oxo-1,2,3-benzotriazine) in DMF. A small amount of diastereomer yielded during the reaction was easily separated by HPLC purification and the highly pure devices were obtained for most of the proteinogenic amino acids.     

Thermodynamics of the O2/O2− redox couple in molten (LiCl + KCl + Li2O) systems

Activity coefficients of oxide ion were determined by the measurements of the standard formal potential of O₂/O^2? with a boron-doped diamond (BDD) electrode in molten (LiCl + KCl): LiCl:KCl = {58.5:41.5 (eutectic), 65:35, 70:30, 75:25} mol% at T = (673 to 803) K. The activity coefficient decreases with the increase of the LiCl content in the melt: (18.7 ± 1.5, 7.7 ± 1.0, 4.1 ± 0.4, and 1.6 ± 0.1), respectively, at T = 773 K in each melt. The result is explained by the attractive force between Li⁺ and O^2? which is stronger than that between K⁺ and O^2?.     

Detection of adrenaline on poly(3-aminobenzylamine) ultrathin film by electrochemical-surface plasmon resonance spectroscopy

In this Article, we present a novel method to detect adrenaline on poly(3-aminobenzylamine) (PABA) ultrathin films by electrochemical-surface plasmon resonance (EC-SPR) spectroscopy. We prepared a PABA film, which specifically reacts with adrenaline, on a gold electrode by electropolymerization of 3-aminobenzylamine. The specific reaction of benzylamine within the PABA structure with adrenaline was studied by XPS, UV-vis spectroscopy, and EC-SPR techniques. Adrenaline was detected in real time by EC-SPR spectroscopy, which provides simultaneous monitoring of both optical SPR reflectivity and electrochemical current responses upon injecting adrenaline into the PABA thin film. The number of changes in both current and SPR reflectivity on the injection of adrenaline exhibited the linear relation to the concentration, and the detection limit was 100 pM. The responses were distinctive to those for uric acid and ascorbic acid, which are major interferences of adrenaline.     

Synthesis of 3-methyl- and 3,4-dimethylfurans using alkoxide,thiolate, and phenoxide-mediated cyclization of 4-oxahepta-1,6-diynes bearing sulfur and selenium functional groups

We have reported sodium alkoxide- or aryloxide-mediated cyclization of 4-oxahepta-1,6-diynes bearing the phenylsulfanyl group 1a–d. The reactions with diverse sodium alkoxides and aryloxide produced 4-alkoxymethyl- and 4-aryloxymethylfurans 2aa–2db in good to high yields. Although reactions with sodium benzenethiolate yielded 3,4-bis(phenylsulfanylmethyl)furans 5a–g, they readily desulfanylated in the presence of tributyltin hydride/AIBN to give the 3-methyl- and 3,4-dimethylfuran derivatives 6a–g. This method’s utility was demonstrated by the synthesis of tetrahydronaphthalenyl furan derivatives bearing alkoxy- and aryloxymethyl substituents.     

Cross-Coupling of Aryllithiums with Aryl and Vinyl Halides in Flow Microreactors

The use of Pd catalysts that contained a carbene ligand, such as PEPPSI-SIPr, speeded up the Murahashi coupling of ArLi with ArBr, by enabling its integration with the Br/Li exchange of ArBr with BuLi in flow. Space integration realized the rapid cross-coupling of two different ArBr substrates. However, the cross-coupling reaction with vinyl halides could not be achieved under similar conditions. Pd(OAc)₂ was an effective catalyst, and the space integration of the Br/Li exchange of ArBr with BuLi and the Murahashi coupling with vinyl halides was successfully achieved.