The application of molecular tethers in controlling axial chirality

Atropisomeric biaryl compounds are an attractive target in organic chemistry due to their abundance in nature and their utility as ligands in catalysis. Among the methods available for their synthesis, the use of chiral tethers offers very high levels of stereocontrol. In this article, we review the application of molecular tethers in controlling axial chirality across a range of different ligands and natural products

Recent applications of gallium and gallium halides as reagents in organic synthesis

This review highlights the application of gallium metal and gallium halides as reagents in organic synthesis. Owing to their unique catalytic properties, gallium trihalides are considered effective Lewis acids which can activate several functional groups under extremely mild conditions. Gallium halides have been successfully employed as Lewis acid catalysts in various organic transformations such as alkylation, allylation, radical reactions, cycloaddition reactions, Friedel-Craft’s reactions and various coupling reactions. This review seeks to update organic chemists about the potential application of gallium halides in the synthesis of a wide variety of chemical building blocks

Model studies toward the synthesis of the bioactive diterpenoid, harringtonolide

In model studies towards the synthesis of harringtonolide, the construction of the tropone moiety via arene cyclopropanation was investigated. The installation of the lactone ring was accomplished by way of a Diels-Alder cycloaddition of various indenones and \u1d6fc-pyones. The incorporation of the key bridge methyl group and subsequent control of its stereochemistry is also outlined

Synthesis of fluorinated oxygen- and sulfur-containing heteroaromatics

Milk protein concentrate (79% protein) reconstituted at 13.5% (w/v) protein was heated (90 °C, 25 min, pH 7.2) with or without added calcium chloride. After fractionation of the casein and whey protein aggregates by fast protein liquid chromatography, the heat stability (90 °C, up to 1 h) of the fractions (0.25%, w/v, protein) was assessed. The heat-induced aggregates were composed of whey protein and casein, in whey protein:casein ratios ranging from 1:0.5 to 1:9. The heat stability was positively correlated with the casein concentration in the samples. The samples containing the highest proportion of caseins were the most heat-stable, and close to 100% (w/w) of the aggregates were recovered post-heat treatment in the supernatant of such samples (centrifugation for 30 min at 10,000 × g). κ-Casein appeared to act as a chaperone controlling the aggregation of whey proteins, and this effect was stronger in the presence of αS- and β-casein

Preparation of γ,δ-unsaturated-β-ketoesters: Lewis acid-catalysed CH insertion of ethyl diazoacetate into α,β-unsaturated aldehydes

The synthesis of γ,δ-unsaturated-β-keto esters was achieved by the Lewis acid-catalysed direct CH insertion of an α-diazoester into various α,β-substituted-unsaturated aldehydes. CH insertion of ethyl diazoacetate into alkyl- and aryl-substituted α,β-unsaturated aldehydes was performed under mild conditions to afford the corresponding γ,δ-unsaturated-β-keto esters in moderate to high yields as a mixture of keto/enol tautomers

Recent advances in the transesterification of β-keto esters

The ability to selectively transesterify β-keto esters is a useful transformation in organic synthesis. The increasing interest in transesterification for the synthesis of compounds of pharmaceutical importance, as well as for biodiesel production, has led to the development of a variety of different approaches. This article aims to summarise recent advances in the transesterifications of β-keto esters. Particular interest has been paid to methodologies with minimal environmental impact

Synthesis and biological evaluation of novel thionucleosides

The search for novel nucleosides has been a major research focus in medicinal chemistry for several decades, particularly given their proven track record in the treatment of viral infections and cancer. As bioisosteres of natural nucleosides, thionucleosides are especially attractive targets as they often display improved biological activity. Furthermore, the replacement of oxygen with sulfur may sometimes be accompanied by interesting changes in pharmacological effect. This update covers recent advances in the preparation of novel thionucleosides, grouped by synthetic strategy. The biological properties of the target thionucleosides are also summarised, in addition to any reported structure activity relationships

Advances in the synthesis of acyclic peroxides

Peroxide-containing compounds are an attractive synthetic target, given their widespread abundance in nature, with many displaying potent antimalarial and antimicrobial properties. This review summarises the many developments in the synthesis of acyclic peroxides, with a particular focus on the past 20 years, and seeks to update organic chemists about these new approaches. The synthetic methodologies have been subdivided into metal-catalysed reactions, organocatalytic reactions, direct oxidation reactions, miscellaneous reactions and enzymatic routes to acyclic peroxides

Modern synthetic approaches to phosphorus-sulfur bond formation in organophosphorus compounds

Phosphorothioates, phosphonothioates, phosphinothioates and phosphonodithioates are organophosphorus compounds with widespread application, especially in the fields of agrochemicals, medicinal chemistry and materials chemistry. Herein, we review modern methods for the construction of the phosphorus-sulfur bonds in these important functional groups. This review is organised on the basis of the different synthetic approaches, with the advantages and disadvantages of each also examined

Synthesis and application of phosphonothioates, phosphonodithioates, phosphorothioates, phosphinothioates and related compounds

Methods for the preparation of phosphonothioates, phosphonodithioates, phosphorothioates, phosphinothioates and related compounds are reviewed. The application of these compounds as synthetic intermediates is also discussed