Christian Alexandre

Synthesis of Substituted Dicyanomethylendihydrofurans

Abstract A simple and efficient method for the preparation of the title compounds is described from α-ketols and malononitrile in the presence of sodium ethylate at room temperature. These compounds lead to unsaturated derivatives by condensation with aldehydes.

Enzymatic acylation of cyclobutene and cyclobutane meso-diols at low temperature

Abstract Acylation of cyclobutane and cyclobutene diols 5 and 8 in the presence of Pseudomonas fluorescens lipase below room temperature led to monoacetates (+)- 6 and (−)- 9 , respectively. The chemical yields and enantiomeric excesses were nearly quantitative.

A short route to new cyclobutene nucleoside analogues

Abstract Nucleoside analogues (+)-4a and (+)-4b were obtained in non-racemic form by a short and efficient way. The key step was a Mitsunobu reaction of alcohol (−)-8 with adenine or protected thymine. The title products were obtained after deprotection steps.

An efficient synthesis of dienic nucleoside analogues via a Mitsunobu reaction

Nucleoside analogues 9 and 12 were obtained in good yields from alcohol 7 which, under Mitsunobu conditions, led to the title products after deprotection steps.

Preparation et reactions de Diels et Alder des alcenyl-5(3H)-furannones-2

Abstract Isomerization of readily available 5-alkenyl 2-(5 H )-furanones 1 generated from aldehydes and propiolate anion to 5-alkenyl 2-(3 H )-furanones 2 by base treatment provides a new and convenient access by mild Diels-Alder reaction in water to substituted cyclohexanofuranones.

A Convenient Synthesis Of Substituted 3-Pyrrolin-2-ones from α-Cetols

Abstract A simple and efficient method for the preparation of the title compounds is described from cyanoacetamides and 3-hydroxy-3-methyl-2-butanone in the presence of sodium ethylate at room temperature. The 3-carboxamido-N-alkyl-4, 5, 5-trimethyl-5-dihy dro-2H-pyrrol-2-ones lead to unsaturated derivatives by condensation with aldehydes, while hydrogenation give rise to the corresponding pyrrolidin-2-ones.

Synthese et reactions de Diels-Alder des 5-alcenyl(3H)furan-2-ones☆

Resume Treatment of (5H)-2-furanones with LDA gives the corresponding (3H)-2-furanones which react easily in water with dienophiles to give cycloadducts in good yields and high stereoselectivity.

AN EFFICIENT RESOLUTION OF (+)-P-TOLYLVINYLSULFOXIDE USING (-)-MENTHOL

Abstract The preparation of enantiopure (+)-(R)S and (−)-(S)S-p-tolylvinylsulfoxide using (−)-menthol as a resolving agent is described.

Synthesis and Reactivity of bis-Lactamic Compounds

Abstract A preparation of bis-lactams is described from α-ketols and bis-cyanamides in the presence of sodium ethoxide at room temperature. One of these compounds leads to an unsaturated derivative by condensation with furfural, or to a saturated analogue via catalytic hydrogenation.

Synthesis and Structural Study of (+)-5-Acetyl-6-methyl-5p-tolylsulfinyl-3a,4,5,6-tetrahydro (3H)-Benzofuran-2-one

Abstract an efficient synthesis of the title compound has been developed from 3-phenyl sulfonylpropanoic acid via the butenolide 2. The key synthetic step is a Diels-Alder reaction. A mechanism is suggested.