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The title synthesis is applicable to aromatic, hetaromatic and alkenyl aldehydes and provides Z dehydroamino acids in moderate to high yields.

A straightforward metal-free synthesis of anti-β-hydroxy-α-amino acids is described. The organic base-mediated decarboxylative aldol reaction of cheap, readily available α-amidohemimalonates with various aldehydes afforded under very mild conditions anti-β-hydroxy-α-amido esters in high yields and complete diastereoselectivity. Simple one-pot subsequent transformations enabled the corresponding anti-β-hydroxy-α-amino acids or in a few examples their syn diastereomers to be obtained directly using epimerization conditions.

In the crystal of the title compound, C12H16Se2, the packing is explained by quadrupolar interactions, and the 1,3-diselenane cycle adopts a chair conformation. This compound was synthesized using diselenocyanate and benzaldehyde.

Aiming at the development of green and efficient C–C bond formations (aldol and Mannich reactions), the decarboxylative nucleophilic addition of malonic acid half ester to imines or aldehydes under mild metal-free conditions was studied. A careful control of the temperature and the appropriate choice of the organic base allowed us to obtain β-amino esters or β-hydroxy esters including α-substituted and α,α-disubstituted ones in moderate to excellent yields. 1H NMR monitoring of the reaction unveiled two distinct mechanisms depending on the hemimalonate used. With the unsubstituted substrate, a carboxylic acid intermediate was isolated upon acid quench resulting from the nucleophilic addition of the putative enol carboxylate anion of the hemimalonate to imines/aldehydes before CO2 loss. With substituted hemimalonates, the reaction likely involved an enolate which then added to imines/aldehydes or was competitively protonated. According to the base used, the reaction can be carried out either under solvent free-conditions or in an ionic liquid under mild conditions.

A decisive step forward: A one-step fluorination on modified cinchona alkaloids produced a new range of enantiopure fluorinating agents that display high enantioselectivities in electrophilic fluorination. The first enantioselective synthesis of N-protected α-fluorophenylglycine derivatives was achieved with an enantiomeric excess up to 94 % [Eq. (a); R=Et, CN; HMDS=hexamethyldisilazanide].

Selectfluor™ was shown to be soluble in ionic liquid, thus allowing the ‘green’ electrophilic fluorination of indole compounds in high chemoselectivity and yields.

The synthesis of selectively fluorinated molecules is an important challenge in organic chemistry. This topic has received considerable attention because of the utility of fluorinated compounds in a wide variety of disciplines. There are three types of fluorination depending on whether the fluorine atom is radical, anionic, or cationic. Fluorine radicals are of little synthetic use because of the difficulties in controlling their reactivity. Fluorine is utilized in nucleophilic as well as electrophilic fluorinations Molecular fluorine is the simplest reagent of this type, however, its safe handling is difficult. Stable, selective reagents are crucial to the development of electrophilic fluorination. N-F reagents have emerged as generally safer and easier to handle selective sources of electrophilic fluorine. N-F reagents offer a range of fluorinating powers and some are available commercially. Two classes are known: neutral N-F reagents and quaternary ammonium N-F reagents (quaternary salts are usually the more powerful). N-F reagents popularity arises because they posses a long shelf life, several are commercially available, and they can be handled safely in glassware. The drawback is the preferential use of molecular fluorine for their preparation. This article deals with the preparation and the use of all types of electrophilic fluorinating agents possessing the N-F moiety. Keywords: Electrophilic fluorination, N-F reagents; N-Fluorosulfonamides; N-Fluorosulfonimides; N-Fluorocarboxamides; N-Fluoro heterocycles; N-Fluoroammonium compounds; N-Fluoroiminium compounds; Alkanes; Heterocycles; Glycals; Metal enolates; Carbonyls; Direct fluorination; Organophosphorus compounds; Organosulfur compounds; Fluorodemetalation; Diastereoselectivity; Enantioselectivity; Method comparisons; Experimental procedures

The enantioselective decarboxylative protonation (EDP) of malonic or acetoacetic acid derivatives is a synthetic methodology by which the chirality of the product is generated during the enol/enolate protonation step. Although EDP is a century-old reaction, it has not received much attention until recently. This review focuses on the EDP as an alternative to the strong-base-mediated deprotonation/asymmetric reprotonation for the stereocontrol of C–H bond formation. The diverse synthetic approaches are classified according to the type of catalysis used, which are organic, metallic or enzymatic.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

New SILP catalysts based on chitosan-supported ionic liquid were successfully applied to allylic substitution reactions. A high level of activity combined with recyclability and reusability were obtained in the amination reaction. No organic solvent was used. The scope and limitations of the reaction using these new SILP catalysts were estimated.

[reaction: see text] A very rapid access to cyclohexanone-bridged indole systems was established by an acid-mediated ring closure of appropriately substituted indole aldehydes, which involved an apparent disproportionation of an aldol-like intermediate. One of the bridged indole intermediates was further transformed into an oxindole having the essential skeleton of the Welwitindolinone alkaloids.

Reaction of the nitriles (I) with tert-butyl chloride (II) in the presence of FeCl3 at -80°C yields the ketene imines (V).