Jean Moulines

Payne-like rearrangement of N-tosyl-oxiranemethylamines : a new route to functionalized aziridines

Abstract The reaction of N-tosly-oxiranemethylamines with aqueous sodium hydroxide affords N-tosyl-aziridinemethanols in excellent yields, through the intramolecular epoxide ring opening by the nitrogen atom of the tosylamino group.

Cyclisation de N-tosyl oxiranes-propylamines: Synthese d'heterocycles azotes.

Abstract The cyclisation of N -tosyl-oxiranepropylamines is accomplished in aqueous basic medium and in anhydrous acid medium as well. In most cases, this reaction occurs by a regiospecific 5- exo-tet . ring closure and affords N -tosyl-2-pyrrolidinemethanols in high yields. The formation of N -tosyl-3-piperidinols through endo attack on the epoxide linkage is observed only in systems exhibiting geometric constraints in the transition state. These cyclisations are accompanied by inversion of configuration at the carbon undergoing nucleophilic attack. Thus, the N -tosyl-oxiranepropylamines cyclisation opens up an efficient entry to functional pyrrolidines and is expected to find useful applications in synthesis.

A PRACTICAL SYNTHESIS OF AMBROX® FROM SCLAREOL USING NO METALLIC OXIDANT

The commercial synthesis of Ambrox® is modified so that the key intermediate, the sclareolide, results from an indirect oxidative degradation of sclareol. This method allows to greatly alleviate the waste disposal problem and to raise the overall yield of Ambrox® to 75%.

Synthesis of 4-phosphono- and of 4-(phosphonomethyl)-dl-phenylalanine, two analogues of O-phosphotyrosine

Abstract :4-Phosphono-DL-phenylalanine 1 was synthetized from 4-bromo-DL-phenylalanine or from 4-(bromomethyl)-bromobenzene ; 4-(phosphonomethyl)-DL-phenylalanine 14 was prepared from methyl p-toluate. The interest of these phosphonic analogues arises from their possible interference in the metabolism of O-phosphotyrosine.

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.

Transposition des oxirannes-ethanols par l'intermediaire d'alcoxyetains

Abstract Oxiraneethoxytributyltins prepared from the corresponding oxiraneethanols, on heating at ∼ 200° gave, after demetalation with isophthallic acid, 2-oxetanemethanols and/or 3-oxolanols. As appears from about thirty rearrangements the choice between oxetane and oxolane formation is dependent on: (1) the relative degree of substitution of the oxirane ring; cyclization occuring predominantly at the more substituted carbon; and (2) the configuration of the oxirane ring, when both its ends are equally substituted; cis form being more suitable for generation of the smaller ring. The reaction is shown to proceed with inversion of configuration at the site of oxygen attack. The results of attempts to perform the rearrangement in dilute-phase or through alkaline metal alkoxides in various media support the conclusion that there is a large contribution by electrophilic assistance to the oxirane opening. Such assistance can be efficiently provided by a tin atom in a push-pull mechanism which accomodates all the facts. The present method of oxiraneethanol rearrangement may offer a convenient route to functional oxetanes.

Transposition des oxirannes-ethanols par l'intermediaire d'alcoxyetains. Influence de la configuration de l'oxiranne

Abstract The transposition of oxirane-ethanols, through alkoxytin compounds, into oxetane-2-methanols and/or oxolan-3-ols (tetrahydrofuran-3-ols) is dependent upon the oxirane configuration. Cis configuration is more suitable for the formation of the smallest ring. Steric hindrance is not sufficient enough to explain the results.

Substituent control in the synthesis of azetidines and pyrrolidines by N-tosyl-oxiraneethylamines base-mediated cyclization

Abstract N-tosyl-oxiraneethylamines undergo cyclization upon treatment with aqueous sodium hydroxide to afford either N-tosyl-azetidinemethanols or N-tosyl-pyrrolidin-3-ols in high yields. The change in regioselectivity of this cyclization process is quite dependent on the location of a pentamethylene substitution in the chain connecting the nitrogen with the oxirane ring.

A Short and Efficient Synthesis of (+)-13-Epimanoyl Oxide from Sclareol

Abstract (+)-13-Epimanoyl oxide has been synthesised in four steps from natural sclareol in an overall yield of 78%; preparation of the related labdane-14,15-diols is involved in this synthetic pathway.