Synthesis and physical properties of zethrene derivatives bearing donor/acceptor substituents at 7,14-positions.

Zethrene derivatives substituted by phenylethynyl groups bearing electron-donating and/or accepting groups were synthesised by iodine-induced transannular cyclisation of dehydrodinaphtho[10]annulene as the pivotal step followed by Sonogashira coupling reaction. Their physical properties were investigated to elucidate the effects of the substituents on the electronic configuration of the zethrene backbone.

Cesium carbonate-catalyzed alpha-phenylchalcogenation of carbonyl compounds with diphenyl dichalcogenide.

It was found that cesium carbonate has a unique catalytic ability on the reaction of carbonyl compounds with diphenyl diselenide to give the corresponding alpha-phenylseleno carbonyl compounds in moderate to good yields. Similarly, the alpha-phenylthiolation of carbonyl compounds with diphenyl disulfide was promoted by the cesium carbonate catalyst.

Tetradehydrodinaphtho[10]annulene: a hitherto unknown dehydroannulene and a viable precursor to stable zethrene derivatives.

The synthesis and structural characterization of hitherto unknown tetradehydrodinaphtho[10]annulene, a hydrocarbon whose synthesis had been attempted four decades ago, was achieved for the first time. Moreover, the dinaphtho[10]annulene was transformed smoothly into stable zethrene derivatives substituted at its 7,14-positions, showing that it serves as a good reservoir of zethrene derivatives. Optical and electrochemical properties of a disubstituted zethrene derivative are also presented.

Ag-catalyzed stereoselective cyclohexadienyl transfer: a novel entry into arylphenylmethanols.

The letter describes a novel concept for the synthesis of biologically important arylphenylmethanols. Stereoselective cyclohexadienyl transfer from 1,4-cyclohexadienyltributyltin to various aromatic aldehydes using AgOTf/BINAP as a catalyst precursor provides 1,4-cyclohexadienylphen-ylmethanols that are readily oxidized to the corresponding arylphenylmethanols. Fifteen examples are presented.

Desymmetrization of 1,4-cyclohexadienyltriisopropoxysilane using copper catalysis.

The first catalytic desymmetrization in the field of allylsilane chemistry is presented. Desymmetrization of cyclohexadienyltriisopropoxysilane is achieved using coppper catalysis. High diastereo- and enantioselectivities are obtained, and the product dienes are highly valuable building blocks for natural product synthesis.

In-capillary preconcentration of proteins for capillary electrophoresis using a cellulose acetate-coated porous joint.

This work describes the in-capillary preconcentration of proteins using a cellulose acetate-coated porous joint. The capillary wall near the inlet end of a capillary was made porous by HF etching. During the etching process, a voltage was applied across the capillary wall and the electric current across it was monitored.

Size-selective formation of C78 fullerene from a three-dimensional polyyne precursor.

Multicyclic cagelike cyclophanes 2 a and 2 b containing cyclobutene rings have been prepared as precursors of three-dimensional polyynes C78H18 (1a) and C78H12Cl6 (1b), respectively. Laser irradiation of 2a and 2b induced expulsion of the aromatic fragment, indane, to give the three-dimensional polyyne anions C78H18- and C78H12Cl6-, respectively. Whereas the former anion lost only four hydrogen atoms to form C78H14-, complete loss of all hydrogen and chlorine atoms was observed from the latter anion, to yield a C78- ion that has a fullerene structure which was proven by its characteristic fragmentation pattern.

Expanded radialenes with bicyclo[4.3.1]decatriene units: new precursors to cyclo[n]carbons.

A new method for the formation of conjugated polyynes has been developed based on both the rearrangement of vinylidenes to alkynes and the [2+1] cheletropic fragmentation of dialkynylmethylenebicyclo[4.3.1]deca-1,3,5-triene derivatives.