The dihydrofuran template approach to furofuran synthesis

Flash vacuum pyrrolysis of vinyl epoxides provides cis-dihydrofuran carboxylic esters in good yields and diastereoselectivities, which, on base-promoted epimerisation afford the complementary trans series. The compounds provide a viable template for a Lewis acid promoted cyclisation to provide the 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane core found in the furofuran series of natural lignans. This strategy is stereodivergent and can be controlled to provide the exo-exo, exo-endo or endo-endo stereochemistries. The approach has been exemplified in syntheses of the sesamyl furofurans (+/-)-epiasarinin and (+/-)-asarinin.     

Kinetic resolution of alpha-acetoxy N-acyl oxazolidinethiones by a chiral O-nucleophilic acyl transfer catalyst

The kinetic resolution of alpha-acetoxy N-acyl oxazolidinethiones using the chiral, nonracemic O-nucleophilic acyl transfer catalyst 8 is described. The reaction proceeds on a variety of substrates in excellent yields, with s-factors ranging from 17 to 31.     

The determination of zinc,cadmium, lead and copper in human hair by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode after nitrate fusion

Samples of hair are digested with nitric acid and fused with alkali metal nitrates, prior to the determination of Zn, Cd, Pb and Cu by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode. Recoveries from spiked samples range from 91 to 101%. Relative standard deviations vary from 2.6 to 13%, depending on the metal and sample source. Some causes of poor reproducibility are discussed.     

4,5-di(2-pyridyl)-1,2,3-triazolate: the elusive member of a family of bridging ligands that facilitate strong metal-metal interactions

The new click-adduct 4,5-di(2-pyridyl)-1,2,3-triazole acts as a doubly-chelating anionic bridging ligand that forms dinuclear ruthenium(II) complexes which exhibit strong metal-metal interactions.