A new general concept for α,β-unsaturated acyl ammonium catalysis is reported that uses p-nitrophenoxide release from an α,β-unsaturated p-nitrophenyl ester substrate to facilitate catalyst turnover. This method was used for the enantioselective isothiourea-catalyzed Michael addition of nitroalkanes to α,β-unsaturated p-nitrophenyl esters in generally good yield and with excellent enantioselect...

an efficient and simple one-pot approach for the synthesis of 3,4-dihydropyrimidin-2-(1h)-one derivatives using antimony trichloride (sbcl3) as a mild catalyst by means of three-component biginelli reaction between β-keto esters, aldehyde derivatives and urea/thiourea under thermal and solvent-free conditions with excellent yields and short reaction times is reported. this methodology offers se...

A conjugate reduction of α,β-unsaturated thioesters catalyzed by copper hydride using PMHS as stoichiometric reductant has been developed. 1,2-Bis(diphenylphosphino)benzene (BDP) was the most effective ligand for this reduction. Saturated thioesters could be produced in excellent yields when the substituent on the thiol is not sterically-demanding. This protocol was applied to induce the reduct...

Grape composition affects wine flavour and aroma not only through varietal compounds, but also by influencing the production of volatile compounds by yeast. C9 and C12 compounds that potentially influence ethyl ester synthesis during fermentation were studied using a model grape juice medium. It was shown that the addition of free fatty acids, their methyl esters or acyl-carnitine and acyl-amin...

Volatile organic compounds (VOCs), 2-methyl-1-butanol, 3-methyl-1-butanol and 2-phenylethanol, were detected together with β-cyclocitral from the cyanobacterium Microcystis aeruginosa NIES-843. These alcohols were optimally produced after 35 d of culture, during which nitrate nitrogen in the cultured broth became exhausted. Additionally, these alcohols were definitely produced using the 2-keto-...

Degraded limonoids are a subclass of limonoid natural products that derive from ring-intact or ring-rearranged limonoids. Establishment robust synthetic routes to access them could provide valuable materials identify the simplest active pharmacophore responsible for observed biological activities parent molecules. This communication delineates development divergent strategy furnish melazolide B...

A highly efficient asymmetric Mannich-type reaction between α-tetralone-derived β-keto esters/amides and 1,3,5-triaryl-1,3,5-triazinanes was realized in the presence of chiral N,N'-dioxide-Ni(ii) or Mg(ii) complex. A variety of optically active β-amino compounds with all-carbon quaternary stereocenters were obtained in good yields with excellent enantioselectivities. A possible transition state...

deprotection of phosphate, phosphate, and sulfite esters by silica chloride is described. silica chloride is a mild, selective, and effective reagent for cleavage of benzyl and t-butyl esters of the above compounds.

Abstract The base-catalyzed reaction of diethyl 1,3-acetonedicarboxylate with 2-hydroxybenzylidene indenediones was studied. provides a facile and expeditious protocol for the synthesis natural product inspired fluorenone-fused coumarins in good to very yields. This process resembles combination domino Michael–intramolecular Knoevenagel–aromatization–lactonization reactions single step. Althoug...