European Journal of Organic Chemistry

Organocatalyzed reactions carried out in nonclassical solvents such as ionic liquids represent interesting alternatives to established procedures. This combination often leads to improved yields and selectivities, as well as to possible catalyst recycling.

Substituted enamides and enol benzoates are readily prepared with a high diastereoselectivity in a one-pot procedure consisting of a regiocontrolled Mitsunobu reaction with convenient nucleophiles, followed by allylboration of aldehydes.

Innovative macrocyclic amidinoureas were synthesised from linear di-Boc-guanidino-alkylamines related to guazatine. Macrocyclization proceeds under mild conditions affording 11- to 16-membered rings with anew and previously undescribed structure in good yields. The synthesis of enantiomerically pure macrocyclic amidinoureas was also accomplished.

A short, enantioselective Lewis acid catalyzed synthesis of some 3,4-benzo-5-oxacephams is reported. The absolute configuration of the title compounds was established by CD spectroscopy.

The dizinc complex of a dinucleating ligand built on a m-terphenyl scaffold was tested for binding to anions and complexometric indicators under physiological conditions. Colorimetric and fluorescence-based indicator displacement assays with selectivity for pyrophosphate over other anions were achieved with Zn₂L2 as the receptor component.

Serine-based amino-functionalized neoglycolipids were prepared by solid-phase synthesis using a carbamate-linker strategy and monitoring with gel-phase ¹⁹F NMR spectroscopy. The terminal amine obtainedafter cleavage was conjugated to amino-functionalized microtiter plates using didecyl squarate and the array was successfully probed with a galactose-binding lectin.

The use of laccase-lipase cocatalytic system to catalyze domino reaction of catechols and nucleophilic reagent, 1,3-dicarbonylcompounds and anilines, affords the corresponding products in a good yield in aqueous medium at room temperature.

Linkage does not matter for indole as DNA base substitution: The synthetic incorporation of indole as an artificial DNA base into oligonucleotides by two different structural approaches is described. The natural-like indole nucleoside In destabilizes DNA duplexes as much as the non-nucleosidic surrogate In′ that connects the phosphodiester bridges by a glycol unit.

Chelate-Claisen rearrangement of a chiral allylic ester allows the synthesis of the unusual epoxyketo amino acid Aoe found inchlamydocin, one representative of a group of peptide-based HDAc inhibitors.

2,5-Disubstituted tetrahydrofurans can be obtained in a trans/cis ratio of up to 93:7 by the addition of an achiral N-acetyloxazolidine-2-thione to a lactol acetate. The diastereoselectivity depends on the nature of R¹ and R² on the achiral reagent.

A selective O-acylation of hydroxyproline in CF₃CO₂H makes a range of proline derivatives available on large-scale without any use of chromatographic purification orprotecting groups, both catalytically active proline amphiphiles and an interesting new high-load proline polymer.

Gabosine A and N were prepared in 8–9 steps from ribose. The key step is a zinc-mediated tandem reaction between 1 and 2 to afford diene 3. Subsequent ring-closingmetathesis yields the corresponding cyclohexene which is then converted into the two natural products.

A mannose n-pentenyl orthoester (NPOE) glycosylates regioselectively myo-inositol orthopentenoate at the equatorial OH, whereas phenyl tetra-O-benzyl-D-mannose thioglycoside was less discriminant givingmixtures of axial and equatorial disaccharides. As noted previously, the preferred site for glycosylation of NPOEs coincides with that of selective acylation with the system RCOCl/pyridine.

The de novo access to “projuglone” C-naphthyl glycosides has been investigated through a [4+2] heterocycloaddition route. Two original dienophiles, conveniently protected at phenolic positions, were synthesized and stereoselectively led to the expected heteroadducts. This work presents the first attempts to apply the HyBRedOx sequence to the synthesis of projuglone C-naphthyl glycosides.

Cu^I-modified zeolites were used for the first time as catalysts for the synthesis of diynes by homocoupling of terminal alkynes. Zeolites exhibiting internal large cage frames, Cu^I–USY and Cu^I–Y, proved to be the best catalysts. High and usually quantitative yields were obtained with a largevariety of alkynes, including carbohydrate derivatives.

Reactions between benzyl alcohols or tert-butyl alcohol and nitriles carried out in the presence of catalytic amounts of o-benzenedisulfonimide are described. The catalyst was recovered with economic and ecological benefits.

Enantiopure monoacid side-chains of esters of cephalotaxine have been prepared. The strategy used as key intermediate the chiral nonracemic epoxide 11a prepared from monomethyl itaconate (8). Ring-opening of epoxide 11a by using different organocuprate nucleophiles followed by hydrogenolysis gave the monoacid side-chains of the corresponding esters of cephalotaxine in moderate to good overall yields.