An enantioselective vinylogous umpolung addition of deconjugated butenolides to allenoates has been developed for the first time with the help of synergistic combination of an achiral phosphine and a chiral squaramide, and represents the first example of a catalytic enantioselective Cγ-Cγ bond formation between two different carbonyl partners.

The first example of a catalytic asymmetric vinylogous Povarov reaction is presented. 1-N-Acylamino-1,3-butadienes react selectively at their terminal double bond in the presence of a chiral phosphoric acid catalyst, delivering highly enantioenriched 1,2,3,4-tetrahydroquinolines bearing a synthetically versatile enecarbamate group at the 4-position.

a simple and reliable electrochemical sensor based on cobalt oxide nanoparticles modified glassy carbon electrode (gce/cooxnps) for determination of butylated hydroxyanisole is presented here. the nanoparticles were fabricated by electrodepositing method. the modified electrode shows excellent catalytic activity toward butylated hydroxyanisole oxidation in ph 12.0 phosphate buffer solution (pbs...

background diatomite coated by nanoparticles of copper and zinc mixed oxides were used to investigate catalytic oxidation of carbon monoxide. objectives aim of this paper was to investigatediatomite performance as a supporting host to confine the cuo and zno nanoparticles and its catalytic activity for carbon monoxide oxidation. materials and methods the prepared catalysts were characterized by...

The synthesis of S-glycosyl sulfonamides wherein the primary sulfonamide functional group (-SO(2)NH(2)) is directly attached to the anomeric position of a carbohydrate moiety is reported. Our general approach consists of first introducing a thioacetate group at the anomeric center of a per-O-acetylated sugar derivative. From this follows formation of a glycosyl sulfenamide (sugar-SNR(2)), oxida...

Ynamides and ynol ethers undergo intermolecular gold-catalysed reaction with a nucleophilic oxidant to access metal-carbenoid reactivity patterns. A site-specific oxidation/1,2-insertion cascade is used for a general access to functionalised α,β-unsaturated carboxylic acid derivatives and vinylogous carbimates.

Acetylation and CrO(3) oxidation in acetic acid (Angyal and James, Aust. J. Chem. 23: 1209-1221, 1970) was applied to 18 different glyceroglycolipids and glycosphingolipids of known structure. The lipids studied contained from one to five pyranosic monosaccharide units including alpha- and beta-linked glucose, galactose, mannose, and N-acetylgalactosamine and beta-linked N-acetylglucosamine. Mo...