J.Y. Lallemand

L'eldanolide, phéromone des glandes alaires de la pyrale de la canne à sucre, eldana saccharina (wlk.): structure et synthèse de ses deux énantiomères

Abstract The isolation and structure determination of eldanolide, the wing gland pheromone of the male African Sugar Cane Borer, Eldana saccharina (Wlk.) is described. The absolute configuration was determined as (3S, 4R) by comparison of the CD spectra of the natural pheromone with both synthetic enantiomers.

Synthese totale du (±) polygodial, de la drimenine et de composes apparentes a jonction de cycle cis et trans

Abstract Isomerization by base under kinetic or thermodynamic control of the Diels-Alder adduct of 1, 3, 3-trimethyl-2-vinyl-1-cyclohexene with dimethyl acetylene dicarboxylate leads to two isomers which, after catalytic hydrogenation, give in high yield starting materials for synthesis of trans and cis drimanes. A short total synthesis of (±)-polygodial and (±)-drimenine from one of these isomers is described.

A new preparation of furo-2,3b furans, and conformational studies by 2D NMR.

Abstract Perhydro furo-2,3-b furan derivatives have been prepared by iodocyclisation of unsaturated lactols. Structure and conformation have been studied by high resolution “COSY” 2D NMR.

A new synthesis of Δ2-butenolides via stereoselective formation of α,β-ethylenic esters.

Abstract A new synthesis of Δ 2 -butenolides is described which involves stereoselective condensation of an α-silyl ester anion with an α-ketoacetal.

Efficient total syntheses of polygodial and drimenin.

Abstract A short and stereoselective total synthesis of (±) polygodial and drimenin is presented. The efficiency of the synthesis is due to the easy access to intermediate diol 4 and its successful direct oxidation into polygodial.

Structure and synthesis of the wing gland pheromone of the male african sugar-cane borer: Eldana saccharina (wlk.) (lepidoptera,pyralidae)

Abstract The structure of the sex attractant isolated from the wing glands of E.saccharina has been determined by chemical and physical methods as trans -3-methyl-4-dimethylallyl- γ -lactone 1 . The synthesis of racemic 1 is described.

Synthesis of all possible stereoisomers of polygodial

Abstract The three possible isomers of polygodial, epimers at C-9, cis and trans fused, are described. Controlled kinetic and thermodynamic epimerizations allow preparation of all stereoisomers from the same key intermediate.

Structure du reactif d'ivanov et de quelques organometalliques issus des derives phenylacetiques—II : Stereochimie de la condensation avec la t-butyl-4 cyclohex-anone

Abstract Ivanov reagent and some other analogous reagents (phenyl acetique serie) have been condensed with t-Bu-4 cyclohexanone in order to complete investigation of the reactive species. In all the cases, equatorial attack is highly predominant; it let suppose that enolate, detected by NMR, is the reactive species.

Structure du reactif d'ivanov et de quelques organometalliques issus des derives phenylacetiques—I : Etude des solutions par rmn

Abstract Ivanov reagent add several analogous reagents (phenyl acetique serie) have been studied by NMR. In all the cases, an enolate-structure is revealed; no carbaneniate-species could be detected, even in very solvating solvents.

Regioselective Formylation of Substituted Cyclohexanones. An Efficient Route to Highly Functionalized Cyclohexenes

Abstract The need for methods adapted to the synthesis of highly functionalized natural products, encourages us to report an example of a regioselective formylation of a 3-substituted cyclohexanone, which enables us to prepare the dialdehyde 6. It has to be noticed that 6 exhibits a pattern of three vicinal functionalized carbons, the same being encountered, for example, in polygodial and other driman sesquiterpenes1