ω-Hydroxyalkyl-phosphonium salts as “instant-ylid” components : extremely convenient and highly cis-selective synthesis of alkenol-type pheromones

In less than 2 hours, (Z)-alkenols of 97 – 98% stereoisomeric purity may be prepared and isolated (!) if a new type of “instant-ylids” is used.     

Zur zeitlichen Intensitätsänderung von Beugungsreflexen bei der Entwässerung von Salzhydraten

Ohne ZusammenfassungMit 3 Abbildungen und 1 Tabelle     

Further Syntheses of Optically Active Verrucarinic Acid, 43rd Communication of Verrucarins and Roridins

Two new syntheses of verrucarinic acid (2S, 3R-dihydroxy-3-methylpentanoic acid) and its derivatives, suitably protected for the further conversion to macrocyclic trichothecenes, are described. The first one makes use of a diastereoselective alkylation of a (?)-(S)-malic acid ester and the regioselective reductin of one carboxyl function toa methyl group. The second approach involves a stereoselective addition of an allylsilane to a chiral glyoxylate.     

Proton spectra according to the diffraction excitation model

Inclusive proton spectra arising from pp collisions are calculated from the diffraction excitation model. Comparison with the data shows that diffraction dissociation cannot account for a major part of σ_inel at low energies (s ? 50 GeV²), but that it could be the dominant mechanism at ISR energies.