α-Arylation and Ring Expansion of Annulated Cyclobutanones: Stereoselective Synthesis of Functionalized Tetralones

α-Arylcyclobutanones display unique reactivity that makes them valuable synthetic intermediates and target molecules. We describe the preparation of α-aryl- and α-heteroarylcyclobutanones through a direct α-arylation reaction. Problematic fragmentations are avoided by the use of LiO^tBu, which promotes a rapid but reversible self-aldol reaction that slowly releases the enolate required for α-arylation. We also demonstrate the ring expansion of α-arylcyclobutanones, a process that is highlighted in the stereoselective synthesis of 1-methoxy coniothyrinone D.     

Vibrational excitations and structure of C2H4 adsorbed on Cu(100)

The adsorption of C₂H₄ on Cu(100) at 80 K has been investigated by angle-dependent high-resolution electron energy loss spectroscopy (EELS) and low-energy electron diffraction (LEED). Our observations are consistent with a model where the ethene molecule is adsorbed in a configuration parallel to the Cu(100) surface. The molecule-metal interaction is weak and presumably of π character.     

Honeycombs, herringbones and brick-walls; three-fold guest-dependent variation in copper trimesate complexes bearing sulfimide ligands

Reaction of a solution of CuSO(4) and S,S'-diphenylsulfimide, Ph(2)SNH 1, with sodium salts of trimesic acid (H(3)tma) in MeOH gives the 2-D coordination network [Cu(3)(Ph(2)SNH)(6)(tma)(2)] in which each trimesate is bound to three copper centres. Addition of other solvents to the reaction mixture causes a change in the shape of the network. By this route, three forms have been prepared and characterised by X-ray crystallography. These include the known honeycomb, 2, and brick-wall, 3, motifs and a herringbone, 4, arrangement which is novel for transition metal-containing trimesate complexes. Key to the supramolecular isomerism observed is the ability of 1 to facilitate structural isomerism at copper(II) centres. In contrast to 2 in which the copper centres are square planar, 4 is analogous to an inter-allogon, with both planar and tetrahedral copper centres. Also prepared is a related complex which is composed of discrete units of three copper centres. These are further linked into a 2-D network by hydrogen bonds.     

Polymer supported chromium porphyrin as catalyst for polycarbonate formation in supercritical carbon dioxide

A new polymer-supported chromium porphyrin has been prepared and fully characterised; its catalytic activity and recyclability were investigated for the ring-opening copolymerisation of 1,2-cyclohexene oxide (CHO) and carbon dioxide (CO2).     

Ecotypic differences in responses of Arabidopsis thaliana L. to elevated polychromatic UV-A and UV-B+A radiation in the natural environment: a positive correlation between UV-B+A inhibition and growth rate

The effects of supplementary ultraviolet-A (UV-A) and ultraviolet-B+A (UV-B+A) in the natural environment on the growth and morphology of various ecotypes of Arabidopsis thaliana were investigated. The ecotypes investigated were Columbia (Col-4), Landsberg erecta (Ler-0), Cvi-0, Wassilewskija, Enkheim-D, Aa-0 and Di-1. The mutant hy-4 was also used. Results varied with the radiation treatment, ecotype and parameter measured. Plants subjected to elevated UV-A were both insensitive (all parameters Cvi-0 and Col-4) and sensitive. When responses to UV-A occurred they were mostly inhibitory (all significant responses of Di-1 and Enkheim-D, most parameters of Wassilewskija, and some parameters of hy-4), however, promotive affects were observed for some parameters of Aa-0 and Ler-0. Supplementary UV-B+A inhibited all parameters of Di-1 and Enkheim-D and most parameters of Col-4, Ler-0 and hy-4, but Wassilewskija, Aa-0 and Cvi-0 were mostly insensitive. The magnitude of the UV-B+A response varied with ecotype (compare Di-1 with Ler-0). Some ecotypes were sensitive to UV-A but not UV-B+A (Aa-0), whereas others (Ler-0, Col-4) show the opposite sensitivities. A linear relationship is reported between the degree of UV-B+A inhibition of each ecotype and growth rate. The higher the growth rate the more susceptible the ecotype is to UV-B+A inhibition. This relationship holds for the majority of growth parameters measured.     

The Numerical dysfunction

Conclusion  This article proposes, as steps necessary to reverse present trends towards popular innumeracy, that