F. Tonnard

Enchainements heteroatomiques et leurs produits de cyclisation—I : Vinylogues de thioamides comme intermediaires de synthese d'acyl-2 thiophenes, thio-1 pyrannones-2 (thiones), dihydro-5,6 dithiinnes-1,2 dioxydes-1,1 et dithiinnes-1,2 dioxydes-1,1 substitues

Abstract 2-Aminovinyl thioketones react with α-bromoketones, ketenes and sulfenes to give respectively substituted 2-acylthiophens, thiopyran(2H)-2-ones, 5,6-dihydro-1,2-dithiin-1,1-dioxides and 1,2-dithiin-1,1-dioxides by a cycloaddition process in good agreement with predictions based on calculated interactions between 2-aminovinyl thioketones and ketenes.

Enchainements heteroatomiques et leurs produits de cyclisation—III : Réactions de Diels-Alder entre vinylogues de thioamides et diénophiles acryliques fonctionnels linéaires et cycliques. Propriétés chimiques des 2H-thiopyrannes liées aux substituants en position 2 et 3

Abstract The thioamide vinylogues (2-aminovinyl thioketones) react as heterodienes with open-chain and cyclic dienophiles to give substituted 4-amino-3,4-dihydro-2H-thiopyrans, or substituted 2H-thiopyrans and substituted 7 - methyl - 7,7a - dihydro - 5H - thiopyranno[2,3 - c] - 5 - furanones respectively, in good agreement with calculated perturbation energy of second order.

A new route to 2-oxazolines, bis-oxazolines, and 2-imidazoline-5-ones from imidates using solvent-free cycloadditions: Synthesis, chemical properties, and PM3 MO calculations

Abstract The 1,3-dipolar cycloadditions between imidate 1, derived from dimethylaminomalonate and aldehydes 2(a-f), phthalaldehyde 2g, isophthalaldehyde 2h. 4-chlorophenylisocyanate 9a, ethoxycarbonylisothiocyanate 9d as dipolarophiles proceeds regioselectively in good yield using solvent-free conditions. Synthesis of ortho- and meta-bis-(2′-oxazoline-5′-yl)benzenes 6g, 6h are also reported. The regiochemistry and the reactivity in these cycloaddition reactions are rationalized by PM3 MO calculations. The stereoselective demethoxycarbonylation of dimethyl 2-oxazoline-4,4-dicarboxylate 4a is described. The mild hydrolysis of 5-(2-formylphenyl)-2-oxazoline 4g leads to the formation of a new 3,4-dihydroisoquinoline 8h in quantitative yield.

Easy access to substituted selenazine and selenopyran derivatives by a cycloaddition-cyclorersion process

Abstract N′-selenoacylamidines were isolated by condensation of selenobenzamide with orthoamides. [4+2] cycloadditions with electrophilic dienophiles were performed leading to 1,3-selenazine derivatives. Selenoamide vinylogs obtained by thermolysis of 4 H -1,3-selenazines, were the precursors of functionalised selenopyrans or selenophenes.

Regioselectivite de la cycloaddition dipolaire-1,3 de munchnones aux alcenes electrophiles

Abstract The 1,3-dipolar cycloaddition of several substituted Munchnones with methyl α-cyanocinnamate and α-cyanocinnamonitrile leads to 2-pyrrolines which may be aromatized to pyrroles. This study shows the influence of steric factors on the regioselectivity of the reaction which is “ a priori ” difficult to predict.

Diels alder reactions of P-chloro (bistrimethylsilyl) methylene phosphine

Abstract The electrophilic dienophile, P-chloro (bistrimethylsilyl) methylene phosphine reacts with electron poor or rich dienes to give the [47π + 2π] cycloadducts whose structures are determined by NMR. The regiospecificity of the reaction is satisfactorily predicted by the second order perturbation theory.

Synthesis of allyl dichlorophosphines and arsines, precursors of transient 1-phosphadiene and 1-arsadiene.

Abstract O-Silylated dienolates react with PCl3 and AsCl 3 to give the corresponding allyl dichlorophosphines or arsines which are deshydrohalogenated to 1-phospha or arsadiene.

Réaction de P-phényl C-aminophosphaalcénes avec l'oxyde de parachlorobenzonitrile, évolution thermique des adduits

Abstract P-phenyl C-aminophosphaalkenes 1 react with p-chlorobenzonitrile oxides at −20°C leading to 1,2,4-oxazaphospholines 2, which are characterized by NMR and decompose slowly at room temperature. An experimental and theoretical study of their thermal evolution shows that the most probable mechanism involves the formation of an azaphospholine such as 10 which is unstable generating a phenyl phosphinidene. The latter polymerize quickly.