X. Lusinchi

The stereospecific synthesis of a new chiral oxaziridinium salt.

Abstract A new chiral oxaziridinium salt has been prepared from (1S, 2R)-(+)-norephedrine. Enantioselective oxygen transfer to prochiral olefins and sulfides may be performed either stoichiometrically or in a catalytic cycle.

Oxygen atom transfer from a chiral oxaziridinium salt. Asymmetric epoxidation of unfunctionalized olefins

Abstract The synthesis of an optically pure oxaziridinium salt from (1S,2R)-(+)-norephedrine and the study of the asymmetric oxygen transfer reactions from this reagent to unfunctionalized olefins are described.

Transfert d'oxygene sur la double liaison ethylenique a partir d'un sel d'oxaziridinium

Abstract Some examples of transfer of oxygen from on oxaziridinium salt to ethylenic derivatives to give epoxides are described.

Oxygen transfer reactions from an Oxaziridinium tetrafluoroborate salt to Olefins

Abstract Oxaziridinium 5 efficiently epoxidises olefins. It reacts as an electrophilic reagent and does not transfer its oxygen to deactivated double-bonds or carbonyl functions. Epoxidation of cyclic allylic acetates shows a remarkable diastereoselectivity leading to the syn isomer. We propose that the epoxidation reaction proceeds through a one-step process.

A novel electrophilic N-amidation via electron deficient complexes : Action of ferric chloride on N-acetyloxyamides

Abstract The action of FeCl 3 on N-acetyloxyamides leads to electron deficient species which can react intra or intermolecularly with an aromatic group to give oxindoles or analogues.

OXYGEN ATOM TRANSFER FROM A CHIRAL N-ALKYL OXAZIRIDINE PROMOTED BY ACID. THE ASYMMETRIC OXIDATION OF SULFIDES TO SULFOXIDES

Abstract Chiral N-alkyl oxaziridines may be used as reagents for the asymmetric oxidation of sulfides in an acid-promoted reaction leading exclusively to the corresponding sulfoxides A planar transition state geometry seems consistent with the observed stereochemistry which should result from the steric interactions in the transition state. The influence of the solvent and the acid strength on the oxygen transfer reaction are discussed.

Peracid oxidation of an immonium fluoroborate a new example of oxaziridinium salt.

Abstract The second oxaziridinium salt described so far has been prepared by alkylation of an oxaziridine and by oxygenation of an immonium salt. This confirms that this function is indeed accessible, though very reactive.

Studies on the reaction of primary and secondary amines with phenylseleninic anhydride and with phenylseleninic acid

Abstract The dehydrogenation under mild conditions of indolines with phenylseleninic anhydride or acid affords good yields of indoles or of 3-phenylselenenyl indoles. Tetrahydroquinoline and -isoquinoline show comparable behaviour. The dehydrogenation of primary amines gives more complicated mixtures from which nitriles and bis-2-phenylselenenylaldehydes can be isolated.

Improved synthesis of 1,2,4-triazoline-3,5-dione derivatives of ergosterol and a new method for their reconversion to ergosterol

Abstract The ergosterol diene system reacts in excellent yield with a series of 4-substituted 1,2,4-triazoline-3,5-diones generated by in situ oxidation of the appropriate hydrazides with phenylseleninic anhydride or phenylseleninic acid. Diaryltelluroxide and diphenylselenoxide are also efficient oxdants. The diene system can be smoothly regenerated by alkaline hydrolysis.

Action de l'acide paranitroperbenzoique sur le tetrafluoroborate de n-methyl-3,4-dihydroisoquinolinium. Formation d'un sel d'oxaziridinium.

Resume Peracidic oxygenation of an iminium salt 4 derived from N-methyl-tetrahydro-1,2,3,4-isoquinolin- leads to an oxaziridinium salt 3 in the presence of a substoichiometric amount of sodium hydrogen carbonate. In stoichiometric amounts of base, the oxaziridinium salt 3 gives a mixture of N-methyl-isoquinolinium 5 , the opened structure 6 , and starting material 4 . 6 .