Indium-Mediated Allenylation of Aldehydes and Its Application in Carbohydrate Chemistry: Efficient Synthesis of D-Ribulose and 1-Deoxy-D-ribulose

Cationic Amphiphiles Bearing a Diacetylenic Function in the Headgroup: Aggregative Properties and Polymerization

In the wide panorama of diacetylenic lipids, the photoresponsive conjugated 1,3-diyne function is usually encased into the hydrocarbon chain of the amphiphile at a variable distance from the headgroup. Therefore, the polydiacetylene network obtained by polymerization upon UV irradiation of the corresponding liposomes, exploited as sensing function, is embedded in the hydrophobic region of liposomes. Structurally related cationic diacetylenic amphiphiles featuring the conjugated triple bonds proximate to charged nitrogen were synthesized and evaluated in their ability to polymerize under aggregative conditions. The occurrence of polymerization only in certain aggregating conditions was rationalized by nuclear magnetic resonance (NMR) and Langmuir trough experiments.

Indium-mediated C-allylation of melibiose

The indium-mediated allylation reaction has been applied to melibiose, a disaccharidic substrate. This elongation methodology allows for a short, efficient and diastereoselective approach towards complex glycosylated carbohydrate structures. The stereochemical outcome of the key intermediates, allylated disaccharides, has been determined by X-ray analysis. Ozonolysis of the introduced double bond yielded the unprotected elongated disaccharides in the equilibrium of the pyranoid as well as furanoid isomers in both anomeric forms, respectively. Per-O-acetylation has been performed to facilitate separation of the isomeric mixture for structural identification. The main product revealed to adopt a β-pyranoid form of the elongated unit at the reducing end of the disaccharide.

The metal tin promoted cascade reaction of ketones in aqueous media for the construction of 2-bromo-4-aryl-1,3-pentadiene

A novel type of transformation was discovered serendipitously during the Barbier-type allenylation reaction of aromatic ketones promoted by the metal, tin, in aqueous media. Additionally, a series of new, highly functionalized 2-bromo-4-aryl-1,3-pentadienes could be obtained with good yields in this reaction. This cascade reaction shows the unique properties of the metal, tin. Furthermore, it is actually a cascade reaction which involves two steps: one is the Barbier-type allenylation of the carbonyl compound, and the other is an SN2' type addition-elimination reaction. Notably, this reaction has the advantages of simple, mild conditions and is easy to operate. Furthermore, the corresponding product could be applied to various coupling reactions or other diversified transformations.

Gram scale synthesis of 3-fluoro-1-hydroxyacetone phosphate: a novel donor substrate in rabbit muscle aldolase-catalyzed aldol reactions

An efficient gram scale synthesis of 3-fluoro-1-hydroxyacetone phosphate (FHAP) has been developed. As a close analog to dihydroxyacetone phosphate, FHAP was used as a novel donor substrate for rabbit muscle aldolase catalyzed reactions. The different binding affinities of the gem-diol and keto form of FHAP were studied by (19)F-NMR.