A new method for the synthesis of carba-sugar enones (gabosines) using a mercury(II)-mediated opening of 4,5-cyclopropanated pyranosides as the key-step

Formal Glycosylation of Quinones with exo-Glycals Enabled by Iron-Mediated Oxidative Radical-Polar Crossover

The intermolecular C-O coupling reaction of 1,4-quinones with exo-glycals under iron hydride hydrogen atom transfer (HAT) conditions is described. This method provides a direct and regioselective access to a wide range of phenolic O-ketosides related to biologically relevant natural products in diastereomeric ratios up to >98:2 in the furanose and pyranose series. No trace of the corresponding C-glycosylated products that might have resulted from the radical alkylation of 1,4-quinones was observed. The results of mechanistic experiments suggest that the key C-O bond-forming event proceeds through an oxidative radical-polar crossover process involving a single-electron transfer between the HAT-generated glycosyl radical and the electron-acceptor quinone.

Oxazole-Based Compounds As Anticancer Agents

Heterocyclic compounds represent a significant target for anti-cancer research and drug discovery, due to their structural and chemical diversity. Oxazoles, with oxygen and nitrogen atoms present in the core structure, enable various types of interactions with different enzymes and receptors, favoring the discovery of new drugs. Aim of this review is to describe the most recent reports on the use of oxazole-based compounds in anticancer research, with reference to the newly discovered iso/oxazole-based drugs, to their synthesis and to the evaluation of the most biologically active derivatives. The corresponding dehydrogenated derivatives, i.e. iso/oxazolines and iso/oxazolidines, are also reported.

5'-Spiro-cyclopropanated lactose derivatives as suitable intermediates for the chain elongation: synthesis of a new 6-deoxy-6-methyl δ-eptulose

A δ-dicarbonyl heptose has been prepared through an electrophilic ring opening procedure of a 5'-spirocyclopropanated lactose derivative. The reported synthetic procedure outlines a new route for the transformation of this renewable disaccharide into new and interesting δ-dicarbonyl sugars, synthetic precursors of cyclitols, carba- and azasugars. The experimental results of the cyclopropanation process have been successfully rationalized by in silico studies.

Synthesis of SL0101 carbasugar analogues: carbasugars via Pd-catalyzed cyclitolization and post-cyclitolization transformations

A general approach to the stereoselective synthesis of 5a-carbasugars has been developed. The route mimics our palladium-catalyzed glycosylation/postglycosylation approach to carbohydrates in that it also utilizes a highly regio- and stereospecific palladium-catalyzed allylation and postglycosylation reaction sequence for the installation of either D- or L-cyclitols. This cyclitolization/postcyclitolization sequence was used for the enantioselective synthesis of a cyclitol analogue of SL0101, its D-sugar enantiomer, as well as several acetylation pattern analogues.

Towards the synthesis of new dideoxy delta-dicarbonyl heptoses

The preparation of a delta-dicarbonyl sugar thorough ring-opening, by a methoxymercuration-demercuration procedure, of a 5-spirocyclopropanated d-galactose derivative, is reported. This method constitutes a new route for the transformation of a hexose into new and interesting delta-dicarbonyl sugars, synthetic precursors of cyclitols, carba- and azasugars. Moreover this is, to our best knowledge, the first reported example of an elongation to a higher sugar starting from a spirocyclopropanated saccharide.