Palladium-catalyzed reduction of enol triflates to alkenes

Enol triflates react with trialkylammonium formate-palladium reagent to give alkenes.     

Chiral 1,3-oxathianes via stereoselective addition-cyclization of hydroxythiols to electron-poor acetylenes

A novel preparation of chiral 1,3-oxathianes via nucleophilic addition of hydroxy-thiols to electron-poor acetylenes, followed by iodine catalyzed photoinduced cyclization is reported. The stereochemical outcome of the reaction is determined with a conformational study based on n.O.e. ¹H-NMR differential spectroscopy experiments.     

Oxidation of 4-chromanones with thallium(III) nitrate

Treatment of 4-chromanones 1a-g with thallium(III) nitrate in acidic methanol results mainly in dehydrogenation, whereas α-methoxylation and/or Taylor-McKillop rearrangement predominate in trimethyl orthoformate. The mechanistic features of these oxidations are briefly discussed.     

Status methodology in isoelectric focussing

Science! true daughter of Old Time thou art! Who alterest all things with thy peering eyes. Why preyest thou upon the poet's heart, Vulture, whose wings are dull realities?     

On the first eigenvalue of the clamped plate

Summary We find a lower bound for the ratio between the first eigenvalue of any homogeneous thin plate G, which is clamped on its boundary, and the first eigenvalue of the spherical clamped plate having the same measure as G. In two dimensions, our bound is about 0.98.     

Scale invariance in disordered systems: the example of the random-field Ising model

We show by numerical simulations that the correlation function of the random-field Ising model (RFIM) in the critical region in three dimensions has very strong fluctuations and that in a finite volume the correlation length is not self-averaging. This is due to the formation of a bound state in the underlying field theory. We argue that this nonperturbative phenomenon is not particular to the RFIM in 3D. It is generic for disordered systems in two dimensions and may also happen in other three-dimensional disordered systems.     

Multifractal properties of return time statistics

The global statistics of the return times of a dynamical system can be described by a new spectrum of generalized dimensions. Comparison with the usual multifractal analysis of measures is presented, and the difference between the two corresponding sets of dimensions is established. Theoretical analysis and numerical examples of dynamical systems in the class of iterated functions are presented.     

Geometric approach to the dynamic glass transition

We numerically study the potential energy landscape of a fragile glassy system and find that the dynamic crossover corresponding to the glass transition is actually the effect of an underlying geometric transition caused by the vanishing of the instability index of saddle points of the potential energy. Furthermore, we show that the potential energy barriers connecting local glassy minima increase with decreasing energy of the minima, and we relate this behavior to the fragility of the system. Finally, we analyze the real space structure of activated processes by studying the distribution of particle displacements for local minima connected by simple saddles.