Nguyen Van Bac

1,3-Dipolar cycloadditions of nitrones to α,β-unsaturated γ-lactams derived from (S)-pyroglutaminol☆

Abstract α,β-Unsaturated γ-lactams undergo regio- and stereoselective 1,3-dipolar cycloadditions with N-benzyl and N-methyl nitrones and can act as acceptors in conjugate addition of N-methylhydroxylamine. These reactions give access to highly functionalized pyrrolidones.

New strategy in the stereocontrolled synthesis of the spiro ketal subunit of milbemycins

Abstract A double Baeyer-Villiger oxidation of bicyclo[2,2,1] heptane-2,5-dione and a stereocontrolled alkylation of the dianion derived from 4-pentyn-2-ol are the salient features of a new strategy in the stereocontrolled synthesis of the spiroketal moiety of milbemycins.

Synthesis of the pheromone of the Comstock mealybug via a sila-Cope elimination

Abstract The synthesis of pheromone 1 of the Comstock mealybug has been achieved via a Sila-Cope elimination during which a new type of 1,2 silicon shift was observed.

Alkylation of diene allylic tertiary amines with grignard reagents. In situ activation with alkyl chloroformates.

Abstract Diene allylic tertiary amines were substituted with Grignard reagents in the presence of lithium tetrachlorocuprate and alkyl chloroformates. According to the experimental condition employed, this reaction afforded exclusively δ-1 V-alkylation products.

Biosynthesis of antitumour alkaloids from Catharanthus roseus. Conversion of 20′-deoxyleurosidine into vinblastine

Administered [aromatic-3H]20′-deoxyleurosidine and [acetyl-14C]20′-deoxyleurosidine are incoporated into vinblastine in Catharanthus roseus.

Asymmetric Michael reactions : enantioselective synthesis of δ-oxo acids

Abstract β-substituted and α,β-disubstituted δ-oxo acids are synthesized with high enantiomeric excess from chiral 2-propenyl oxazolines 8 and 11, whilst 2-vinyl oxazlines 7 and 10 are less efficient asymmetric inductors.

Synthesis of a pheromone of boarmia selenaria via a sila-cope elimination. Stereochemical implications

The use of a Sila-Cope elimination afforded aZ,Z,Z trienamine derivative, direct synthetic precursor of (3Z,6Z,9Z)-3,6,9-nonadecatriene1, one of the pheromone components ofBoarmia selenaria. X-ray analysis of the tetrahydropyridinium salt13 leading to the dienic Vinyl silane14 allowed the determination of the relative configurations of the tetrahydropyridine intermediates7,8,9 and12.

Fragmentation induite par le silicium (II) synthèse stéréo sélective du nonacosadiène-7(Z), 11(Z), phéromone de contact de drosophila melanogaster

Abstract 7(Z), 11(Z)-nonacosadiene 1 , pheromone of Drosophila melanogaster , has been prepared from tetrahydropyridine 3 via a silicon induced fragmentation, a coupling reaction with Grignard reagent and a Wittig olefination.