Total syntheses of shizukaols A and E

Shizukaols possess a common heptacyclic framework containing more than ten contiguousstereocenters and potential biological activities. Here we report that the total syntheses ofshizukaols A (1)and E(2), two lindenane-type dimers from the Chloranthaceae family, areachieved via a modified biomimetic Diels–Alder reaction. The common crucial biomimetic diene23and ethylene species (6,17) are obtained through either a highlyZ-selective olefination ofα-siloxy ketone with ynolate anions or an intramolecular Horner–Wadsworth–Emmons olefinationfrom commercially available Wieland–Miescher ketone (7). This synthetic approach here opensup practical avenues for the total syntheses of the intriguing Chloranthaceae family members, aswell as the understanding of their relevant biological action in natur

tRNA structural and functional changes induced by oxidative stress

Oxidatively damaged biomolecules impair cellular functions and contribute to the pathology of a variety of diseases. RNA is also attacked by reactive oxygen species, and oxidized RNA is increasingly recognized as an important contributor to neurodegenerative complications in humans. Recently, evidence has accumulated supporting the notion that tRNA is involved in cellular responses to various stress conditions. This review focuses on the intriguing consequences of oxidative modification of tRNA at the structural and functional level