B. Maillard

Phase-Transfer Catalytic Alkylation of Hydroperoxides: A Convenient Route to Mixed Dialkyl Peroxides

Abstract The solid-liquid phase transfer catalytic alkylation of hydroperoxides using solid potassium hydroxide as a base and TEBAC as a phase transfer catalyst is reported. When the alkylating agent is a primary bromide, this reaction represents a simple and quick method for the synthesis of mixed dialkyl peroxides in fair yields.

Intramolecular homolytic displacements 7 — Free radical additions to unsaturated peroxy compounds : Synthesis of oxygenated heterocycles

Abstract Free radical additions of hydrogen donor solvents to tert-butyl perpent-4-enoate have given 4-substituted γ-butyrolactones, with yields of 50 % or greater. Such reactions applied to allyl-tert-butyl peroxide have produced 2,3-epoxypropanation of these solvents. Similar addition-elimination processes occurred with tert-butyl 4-methyl-perpent-4-enoate, tert-butyl 2,2-dimethyl-perpent-4-enoate and tert-butyl-methallyl peroxide, but they failed with tert-butyl 5-methyl-perhex-4-enoate and tert-butyl-3-methyl-but-2-enyl peroxide.

Une nouvelle synthèse de peroxydes d'alkyle dissymétriques à partir d alcools tertiaires

Resume Une nouvelle synthese de peroxydes dalkyle dissymetriques est proposee, mettant en jeu laction dun hydroperoxyde dalkyle (1aire, 2aire, ou 3aire) sur un trichloroacetimidate dalkyle tertiare en milieu acide. Les rendements varient entre 30 et 70%.

Synthesis of α,β-epoxyesters by homolytically induced decomposition of derivatives of ethyl 2-(1-hydroperoxyethyl)propenoate

Decomposition of small amounts of tert-butyl peracetate at 110 °C in benzene solutions of derivatives of ethyl 2-(1-hydroperoxyethyl)propenoate afforded α,β-epoxyesters in good yields.

Enzymatic Reactions in Organic Synthesis 4- Hydrolyses of Diesters

Abstract Enzpatic hydrolyses allowed discriminations of esters functions present in the same moiecule.

Déplacements homolytiques intramoléculaires: 27. Décompositions induites de peroxydes allyliques àdouble liaison activée

Resume La thermolyse de peracetate de 2,2-dimethylethyle dans des solutions cyclohexaniques de 2-(1,1-dimethylethylperoxy)methylpropenenitrile, de 2-(1,1-dimethylethylperoxy)methylbut-3-enone et de 3-(1,1-dimethylethyl peroxy)-2-phenylpropene a montreun comportement similaire de ces composes. Deux decompositions induites de ces derives peroxydiques insatures ont etemises en evidence (1) addition dun radical sur la double liaison suivie dune substitution homolytique intramoleculaire sur la liaison O–O; (2) arrachement dun hydrogene en position allylique suivie dune elimination dun radical t-butoxyle.

Anionically induced decomposition of ethyl 2-(2,2-dimethylethylperoxymethyl)propenoate by amines: an easy access to amino epoxyesters and amino ester peroxides

Treatment of ethyl 2-(2,2-dimethylethylperoxymethyl)propenoate with primary and secondary amines led to amino epoxides and/or amino peroxides. These compounds were produced by the addition of the amine to the unsaturation of the peroxide to form a zwitterion, followed, respectively, by a proton transfer and an SNi reaction. The formation of one or the other amino derivative was favoured by different reaction conditions (mode of addition of the reactant, solvent). Easy separation of these compounds was possible by chromatography on silica when the reaction was unselective.

ANIONICALLY INDUCED DECOMPOSITION OF 2-ETHOXYCARBONYLPROP-2-ENYL PEROXIDES

Treatment of 2-ethoxycarbonylprop-2-enyl peroxides with potassium alkylperoxylate, the sodium enolate of diethyl malonate and a primary or secondary amine yields epoxides via a two-step process: (i) addition of the nucleophile to the acrylic unsaturated bond and (ii) intramolecular anionic substitution on the peroxidic bond.

Functional transformation of aldehydes and ketones via homolytic induced decomposition of unsaturated peroxy acetals and peroxy ketals

Induced decomposition of unsaturated peroxy acetals prepared from trimethyl orthoformate, dodecanal or 2-methylundecanal and 2,3-dimethyl-2-hydroperoxybut-3-ene, in the presence of ethyl iodoacetate, CCl4 or dodecanethiol, allowed respectively their iodo-, chloro- and hydro- decarbonylation with yields of over 70%; the same reaction applied to the monoperoxy ketal or diperoxy ketal of cyclohexanone in the presence of ethyl iodoacetate resulted in its functional transformation in methyl 6-iodohexanoate or 1,5-diiodopentane with respective yields of 65 and 40%.

Intramolecular homolytic displacements. Part 22. Polar effects in the homolytic induced decompositions of allyl peroxides

The products of the decomposition of allyl peroxides 1–5, initiated by tert-butyl peracetate, in three solvents—cyclohexane, dimethyl malonate and benzene—were analysed. The formation of epoxides proved the existence of an homolytic induced decomposition of the unsaturated peroxides by a chain process involving a free radical addition to the double bond and an intramolecular homolytic substitution on the peroxide linkage. The balance of the reactions products indicated a second way of degradation of the peroxides: allylic hydrogen abstraction followed by the breaking of the peroxide bond by β-elimination. The relative ratios of the products generated by the eliminated alkoxy radicals YO˙ and of the different epoxides produced in these reactions showed the influence of the polar factors in the various steps of the homolytic induced decomposition: i.e. hydrogen abstraction to the solvent or to the peroxide and addition to the double bond.