The α,β-unsaturated sulfones are suitable activated olefins in catalytic asymmetric conjugate β-boration. These substrates undergo smooth conjugate addition of bis(pinacolato)diboron [B(2)(pin)(2)] catalyzed by nonracemic Cu(I)-diphosphine complexes to provide, upon subsequent oxidation, β-hydroxy sulfones in good yields and high enantiocontrol.

Enantioselective conjugate addition of bis(pinacolato)diboron to α,β-unsaturated imines proceeds smoothly in water in the presence of a chiral copper(II) complex consisting of Cu(OAc)2 and chiral 2,2'-bipyridine. The corresponding β-boryl imines, which were oxidized to β-hydroxy imines, further leading to γ-amino alcohols, were obtained in high yields and high enantioselectivities.

The cross-coupling reaction of cyclopropanol-derived ketone homoenolates bearing β-hydrogens with aryl and hetaryl bromides has been achieved for the first time. This reaction is high yielding, is broad in scope and uses a simple catalytic system. Notably, the proposed palladium homoenolates do not undergo β-hydride elimination to the corresponding α,β-unsaturated ketones.

The Rh(I) complex of a monodentate phosphoramidite bearing a primary amine moiety (DpenPhos) has been disclosed to be highly efficient for the asymmetric hydrogenation of a variety of α- or β-acyloxy α,β-unsaturated phosphonates, providing the corresponding biologically important chiral α- or β-hydroxy phosphonic acid derivatives with excellent enantioselectivities (90->99% ee).

A building block approach for the synthesis of α,β-diamino acids is described, which involves the diastereodivergent preparation of two sets of orthogonally protected δ,ε-unsaturated α,β-diamino acids as templates for the preparation of 12 new α,β-diamino acids of biological relevance using simple techniques.

TiCl4-promoted aldol reaction of ketones as aldol acceptors followed by elimination of the titanoxy group from the Ti-aldolates affords β,β-disubstituted α,β-unsaturated carbonyl compounds in a one-pot procedure. The use of additives, such as DMF, N,N,N',N'-tetramethylethylenediamine, and pyridine, in the elimination step was found to be important.

Objectives: The objective of this research was to investigate the chemical composition and antibacterial activities of the fatty acids and essential oil from various parts of Ligularia persica Boiss (L. persica) growing wild in north of Iran. Materials and Methods: Essential oils were extracted by using Clevenger-type apparatus. Antibacterial activity was tested on two Gram-positive and two Gra...

objectives: the objective of this research was to investigate the chemical composition and antibacterial activities of the fatty acids and essential oil from various parts of ligularia persica boiss (l. persica) growing wild in north of iran. materials and methods: essential oils were extracted by using clevenger-type apparatus. antibacterial activity was tested on two gram-positive and two gra...

An effective synthesis for syn-β-lactams was achieved using a Rh-catalyzed reductive Mannich-type reaction. A rhodium-hydride complex (Rh-H) derived from diethylzinc (Et2Zn) and a Rh catalyst was used for the 1,4-reduction of an α,β-unsaturated ester to give a Reformatsky-type reagent, which in turn, reacted with an imine to give the syn-β-lactam. Additionally, the reaction was applied to the s...