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A 2-O-benzyl-3,5-O-benzylidene-alpha-d-thioarabinofuranoside was obtained by reaction of the corresponding diol with alpha,alpha-dibromotoluene under basic conditions. On activation with 1-benzenesulfinyl piperidine, or diphenyl sulfoxide, and trifluoromethanesulfonic anhydride in dichloromethane at -55 degrees C, reaction with glycosyl acceptors affords(More)
The differential binding of a number of water-soluble cationic porphyrins to a branched DNA molecule is reported. Tetrakis(4-N-methylpyridiniumyl)porphine (H2TMpyP-4) interacts near the branch point with an immobile DNA junction formed from four 16-mer strands. Its Cu(II) and Ni(II) derivatives show stronger preferential binding in the neighborhood of the(More)
A sequence of a carbonyl addition between 4-alkenyl ketones and aldehydes with trimethylsilyldiazomethane followed by a 1,3-Brook rearrangement and an intramolecular 1,3-dipolar cycloaddition was promoted by Lewis bases tetrabutylammonium triphenyldifluorosilicate (TBAT) or potassium tert-butoxide (KO-t-Bu). Through these concatenated bond-forming(More)
The benzeneselenol-catalyzed, tributyltin hydride-mediated addition of phenolic iodides to benzene gives the 3-(hydroxyaryl)-1,4-cyclohexadienes, predominantly. Under conditions of controlled osmoylation, these are converted to the racemic 1,2-syn-2,3-anti-3-(hydroxyaryl)-4-cyclohexene-1,2-diols, whereas exhaustive osmoylation gives the(More)
An asymmetric method for the synthesis of dihydropyrido[1,2-a]indoles from mixtures of nitrones and allenoates has been developed. This transformation showcases the use of squaramide catalysis in a complicated cascade system that has been shown to be highly sensitive to reaction conditions and substituent effects. The new method provides access to(More)
The effect of charge of the Fe(II) reagent used to induce DNA strand cleavage reactions in the presence of a source of reducing equivalents is investigated using two oligonucleotide models. The first consists of the two strands dA20 and dT20, and an equimolar complex between them. The second is a short four-arm branched DNA complex composed of four 16-mer(More)
A novel three-component coupling (3-CC) reaction of 2-aminoazines, aromatic aldehydes, and diazo-compounds producing polyfunctional β-amino-α-diazo-compounds has been developed. The reaction features an unprecedented heterocycle-assisted addition of a diazo-compound to an imine. The obtained diazoesters were efficiently converted into valuable heterocycles(More)
The isolation and structural characterization of alkynyl Ru-alkylidene species has been elusive owing to their rapid metallotropic shift and fast turnover. The enyne ring-closing metathesis and relay metathesis provides the platform to form a variety of alkynyl Ru-alkylidene species possessing a sterically and electronically different substituent on the(More)