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...

Bibenzyl natural products, such as the amorfrutins, contain a heavily substituted aromatic core and display diverse range of biological activities (anti-tumor, anti-diabetic, antimicrobial, antibiotic). In this study, we report unified syntheses amorfrutin A to D either through total or formal synthesis by employing dual biomimetic strategy polyketide aromatization followed remote terpene funct...

A general approach to asymmetric synthesis of highly substituted dihydroquinolines was achieved through neighboring ortho-amino group engaged sequential Michael/amination/dehydration reactions on (E)-2-(2-nitrovinyl)anilines with cyclic and acyclic β-keto esters in the presence of a catalytic amount of Rawal's quinidine-NH-benzyl squaramide followed by TFA.

The direct electrophilic α-cyanation of β-keto esters and amides has been developed using a hypervalent iodine benziodoxole-derived cyano reagent. The procedure is accomplished within 10 min and without the use of any catalyst in DMF, at room temperature. Thus, the highly functionalized quaternary carbon-centered nitriles were produced in high to excellent yields.

Finely-tuned ruthenium-catalyzed highly chemoselective and enantioselective hydrogenation of γ-halo-γ,δ-unsaturated-β-keto esters at the carbonyl group was achieved under neutral reaction conditions (ee up to 97%). Both olefin and alkenyl halogen moieties, which are labile under hydrogenation conditions, remained untouched during the reaction.

The synthesis of novel chiral coumarins functionalized with proteinogenic amino acid side chains via N-protected γ-amino-β-keto esters and their incorporation into the cell permeable HIV-1 TAT peptide through the modified solid phase peptide synthesis are described.

A facile synthetic route for the preparation of N-protected γ-amino β-keto esters from amino aldehydes and ethyl diazoacetate is described. The two component coupling is facilitated by tin(II) chloride followed by semipinacol rearrangement leading to the product in quantitative yield. The reaction is mild, instantaneous and compatible with Boc-, Fmoc- and Cbz-amino protecting groups.

This review summarizes the chemoenzymatic synthesis of the biologically active natural products based on a combination of chemical diastereoselectivity and enzymatic enantioselectivity using biocatalyst. Asymmetric reduction of 2-methyl-3-keto ester with yeast gave the optically active syn-2-methyl-3-hydroxy ester, which was converted to natural product such as (-)-oudemansin B. Asymmetric hydr...

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...