Peter Quayle

The Pd(0)-catalysed coupling reactions of 2-(tri-n-butylstannyl)-3,4-dihydrofuran and -5,6-dihydropyran.

The palladium(0) catalysed reaction of dihydropyranyl and dihydrofuranylstannanes offers an attractive route to the sythesis of 2-vinylhydropyrans and -furans.

Aqueous ring-opening metathesis polymerization and copolymerization of 2,3-dicarboxylic acid anhydride, 2,3-bis(methoxymethyl) and 2,3-dicarboxylic acid mono-methyl ester derivatives of 7-oxanorbornene

Abstract The aqueous ring-opening metathesis polymerization of 2,3-dicarboxylic acid anhydride (I), 2,3-bis(methoxymethyl) (II) and 2,3-dicarboxylic acid mono-methyl ester (III) derivatives of 7-oxanorbornene was explored. Reactions were catalysed by commercial ruthenium trichloride with aqueous ethanol or water as solvent. The anhydride ring opened during polymerization of I. The rate of polymerization of III exceeded that of II. The copolymerization of II and III was investigated for the case of monomers either mixed initially or added sequentially. Solubility data indicated that statistical copolymers were produced in both cases.

First structurally confirmed example of the formation of a gold(III) carbon bond via transmetallation with a boroxine

Cyclometallated gold(III) complexes containing functionalised (2-dimethylaminomethyl)phenyl ligands have been prepared by transmetallation from boroxines to sodium tetrachloroaurate.

The preparation of β-lactam homoenolates

Abstract The synthesis of 4-(tri-n-alkylstannyl)azetidin-2-ones has been accomplished via a displacement reaction of 4-substituted azetidin-2-ones with tin centred anions. The utility of these intermediates as homoenolates is presented.

Non-linear, cata-Condensed, Polycyclic Aromatic Hydrocarbon Materials: A Generic Approach and Physical Properties.

A generic approach to the regiospecific synthesis of halogenated polycyclic aromatics is made possible by the one- or two-directional benzannulation reactions of readily available (ortho-allylaryl)trichloroacetates (the “BHQ” reaction). Palladium-catalysed cross-coupling reactions of the so-formed haloaromatics enable the synthesis of functionalised polycyclic aromatic hydrocarbons (PAHs) with surgical precision. Overall, this new methodology enables the facile mining of chemical space in search of new electronic functional materials.

Green oxidation reactions - Application to carbohydrate chemistry

Oxidation of glycals by either methyltrioxorhenium (MTO)–hydrogen peroxide or hydrogen peroxide–acetonitrile in methanol provides direct access to methyl glycosides. The two different reagents proceed with a complementary stereochemical outcome enabling the synthesis of β-D-gluco-pyranosides or α-D-manno-pyranosides from the same carbohydrate precursor.

A palladium mediated spiroketal synthesis

A Stork-Negishi olefination-coupling sequence has been applied to the synthesis of spiroketals.

Recombinant silicateins as model biocatalysts in organosiloxane chemistry

Significance Organosiloxanes are components in a huge variety of consumer products and play a major role in the synthesis of fine chemicals. However, their synthetic manipulation primarily relies on the use of chlorosilanes, which are energy-intensive to produce and environmentally undesirable. Synthetic routes that operate under ambient conditions and circumvent the need for chlorinated feedstocks would therefore offer a more sustainable route for producing this class of compounds. Here, a systematic survey is reported for the silicatein enzyme, which is able to catalyze the hydrolysis, condensation, and exchange of the silicon–oxygen bond in a variety of organosiloxanes under environmentally benign conditions. These results suggest that silicatein is a promising candidate for development of selective and efficient biocatalysts for organosiloxane chemistry. The family of silicatein enzymes from marine sponges (phylum Porifera) is unique in nature for catalyzing the formation of inorganic silica structures, which the organisms incorporate into their skeleton. However, the synthesis of organosiloxanes catalyzed by these enzymes has thus far remained largely unexplored. To investigate the reactivity of these enzymes in relation to this important class of compounds, their catalysis of Si–O bond hydrolysis and condensation was investigated with a range of model organosilanols and silyl ethers. The enzymes’ kinetic parameters were obtained by a high-throughput colorimetric assay based on the hydrolysis of 4-nitrophenyl silyl ethers. These assays showed unambiguous catalysis with kcat/Km values on the order of 2–50 min−1 μM−1. Condensation reactions were also demonstrated by the generation of silyl ethers from their corresponding silanols and alcohols. Notably, when presented with a substrate bearing both aliphatic and aromatic hydroxy groups the enzyme preferentially silylates the latter group, in clear contrast to nonenzymatic silylations. Furthermore, the silicateins are able to catalyze transetherifications, where the silyl group from one silyl ether may be transferred to a recipient alcohol. Despite close sequence homology to the protease cathepsin L, the silicateins seem to exhibit no significant protease or esterase activity when tested against analogous substrates. Overall, these results suggest the silicateins are promising candidates for future elaboration into efficient and selective biocatalysts for organosiloxane chemistry.

A synthetic approach to novel carvotacetone and antheminone analogues with anti-tumour activity

A synthetic approach to analogues of the terpenoid natural product antheminone A is described which employs (-)-quinic acid as starting material. A key conjugate addition step proved to be unpredictable regarding its stereochemical outcome however the route allowed access to two diastereoisomeric series of compounds. The results of biological assay of the toxicity of the target compounds towards non-small-cell lung cancer cell line A549 are reported.

Crystal structure of catena-poly[hemi[1,3-bis­(2,6-diisoprop­ylphenyl)imidazolium] [[μ3-acetato-κ3O:O:O′-tri-μ2-acetato-κ6O:O′-dicopper(II)(Cu—Cu)]-μ-chlorido] di­chloro­methane sesqui­solvate]

The title copper(II) complex, {(C27H37N2)[Cu4(CH3COO)8Cl]·3CH2Cl2}n, is a one-dimensional coordination polymer. The asymmetric unit is composed of a copper(II) tetraacetate paddle-wheel complex, a Cl− anion situated on a twofold rotation axis, half a 1,3-bis(2,6-diisopropylphenyl)imidazolium cation (the whole molecule being generated by twofold rotation symmetry) and one and a half of a dichloromethane solvent molecule (one being located about a twofold rotation axis). The central metal-organic framework comprises of a tetranuclear copper(II) acetate ‘paddle-wheel’ complex which arises from the dimerization of the copper(II) tetraacetate core comprising of three μ2-bidentate acetate and one μ3-tridentate acetate ligands per binuclear paddle-wheel complex. Both CuII atoms of the binuclear component adopt a distorted square-pyramidal coordination geometry (τ = 0.04), with a Cu⋯Cu separation of 2.6016 (2) Å. The apical coordination site of one CuII atom is occupied by an O atom of a neighbouring acetate bridge [Cu—O = 2.200 (2) Å], while that of the second CuII atom is occupied by a bridging chloride ligand [Cu⋯Cl = 2.4364 (4) Å]. The chloride bridge is slightly bent with respect to the Cu⋯Cu internuclear axis [Cu—Cl—Cu = 167.06 (6)°] and the tetranuclear units are located about a twofold rotation axis, forming the one-dimensional polymer that propagates along [101]. Charge neutrality is maintained by the inclusion of the 1,3-bis(2,6-diisopropylphenyl)imidazolium cation within the crystal lattice. In the crystal, the cation and dichloromethane solvent molecules are linked to the coordination polymer by various C—H⋯O and C—H⋯Cl hydrogen bonds. There are no other significant intermolecular interactions present.