A series of ruthenium-based metathesis catalysts with N-heterocyclic carbene (NHC) ligands have been prepared in which the N-aryl groups have been changed from mesityl to mono-ortho-substituted phenyl (e.g., tolyl). These new catalysts offer an exceptional increase in activity for the formation of tetrasubstituted olefins via ring-closing metathesis (RCM), while maintaining high levels of activity in ring-closing metathesis (RCM) reactions that generate di- and trisubstituted olefins.

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The direct addition of water and a variety of alcohols to activated olefins was observed in the presence of nucleophilic phosphine catalysts. Unlike existing methods, the reactions proceed at room temperature and in the absence of transition metals, or strong acids or bases. The use of simple commercially available catalysts makes this an attractive method for the preparation of beta-hydroxy and beta-alkoxy substrates, which are prevalent targets and intermediates in organic synthesis. The scope and mechanism of this reaction has been explored, and the compound that acts as the resting state of the catalyst was synthesized independently. Our mechanism also suggests the possibility of extending the scope of this reactivity to other classes of nucleophiles.

Sulfonylaziridines have been identified as excellent monomers for living ring-opening polymerization initiated by nucleophilic sulfonylamides. The resulting polymers exhibit low polydispersities and controllable molecular weights. The enantiopurity of the monomer plays a key role: racemic samples yield soluble polymers of target molecular weights, while enantiopure samples produce insoluble polymers with molecular weights significantly below theoretical values. Dynamic light scattering and kinetics of polymerization are discussed.

Cyanobacterial lipopolysaccharide/s (LPS) are frequently cited in the cyanobacteria literature as toxins responsible for a variety of heath effects in humans, from skin rashes to gastrointestinal, respiratory and allergic reactions. The attribution of toxic properties to cyanobacterial LPS dates from the 1970s, when it was thought that lipid A, the toxic moiety of LPS, was structurally and functionally conserved across all Gram-negative bacteria. However, more recent research has shown that this is not the case, and lipid A structures are now known to be very different, expressing properties ranging from LPS agonists, through weak endotoxicity to LPS antagonists. Although cyanobacterial LPS is widely cited as a putative toxin, most of the small number of formal research reports describe cyanobacterial LPS as weakly toxic compared to LPS from the Enterobacteriaceae.We systematically reviewed the literature on cyanobacterial LPS, and also examined the much lager body of literature relating to heterotrophic bacterial LPS and the atypical lipid A structures of some photosynthetic bacteria. While the literature on the biological activity of heterotrophic bacterial LPS is overwhelmingly large and therefore difficult to review for the purposes of exclusion, we were unable to find a convincing body of evidence to suggest that heterotrophic bacterial LPS, in the absence of other virulence factors, is responsible for acute gastrointestinal, dermatological or allergic reactions via natural exposure routes in humans.There is a danger that initial speculation about cyanobacterial LPS may evolve into orthodoxy without basis in research findings. No cyanobacterial lipid A structures have been described and published to date, so a recommendation is made that cyanobacteriologists should not continue to attribute such a diverse range of clinical symptoms to cyanobacterial LPS without research confirmation.