Jean Boivin

Functionalisation of saturated hydrocarbons. part x.1 a comparative study of chemical and electrochemical processes (gif and gif-orsay systems) in pyridine in acetone and in pyridine-co-solvent mixtures

Abstract Six saturated hydrocarbons (cyclohexane, 3-ethylpentane, methylcyclopentane, cis - and trans -decalin and adamantane) were oxidised by the GifIV system (iron catalyst, oxygen, zinc, carboxylic acid) and its electrochemical equivalent (Gif-Orsay system). Results obtained using various solvents (pyridine, acetone, pyridine-acetone mixtures) were similar for both systems. Total or partial replacement of pyridine with acetone affects the selectivity for secondary positions and lowers the ketone/secondary alcohol ratio. The formation of the same ratio of cis - and trans -decal-9-ol from both cis - and trans -decalin clearly demonstrates that tertiary alcohols result from a mechanism essentially radical in nature.

Selective oxidation of saturated hydrocarbons using an electrochemical modification of the gif system.

Abstract The Gif system for selective hydrocarbon oxidation can be carried out replacing the zinc by a cathodic electrochemical reduction; the yields obtained and the selectivities observed are very similar.

On the mechanism of the gif system for the oxidation of saturated hydrocarbons

Abstract The high selectivity of the Gif system for hydrocarbon oxidation is shown to depend upon the capture of tert. radicals by pyridine; the mechanism for the secondary oxidation products has only a minor radical component as judged by competitive trapping.

Hémisynthèse de nouveaux glycosides analogues de la daunorubicine

Abstract Seven daunorubicin analogs containing α- l -, α- d -, and β- d -glycosidic linkages, in which the natural occurring sugar ( l -daunosamine) was replaced by diastereo-isomeric 3-amino-2,3,6-trideoxyhexoses (3-epi- l -daunosamine, d -acosamine, d -daunosamine, d -ristosamine, and 3-epi- d -daunosamine), were prepared. In all cases, glycosidation with daunomycinone was performed in the presence of p -toluene-sulfonic acid starting from 1- O -acetyl-2,3,6-trideoxy-4- O - p -nitrobenzoyl-3-trifluoroacetamidohexopyranoses (prepared from the corresponding methyl 3-amino-2,3,6-trideoxyhexopyranosides) or from 1,5-anhydro-2,3,6-trideoxy-4- O - p -nitrobenzoyl-3-trifluoroacetamidohex-1-enitols (prepared from glycals or pseudoglycals, the 3-amino group being introduced by substitution with sodium azide and subsequent reduction). Glycosidation was followed by removal of the protecting groups.

Part 1. Reduction of S-alkyl-thionocarbonates and related compounds in the presence of trialkylboranes/air

A new, mild, and environment friendly process for the reduction of S-alkyl-thionocarbonates, iodides and related compounds to the corresponding hydrocarbons at room temperature with good to excellent yields is described. This method uses a trialkylborane in excess (Et3B or Bu3B) and air.

Selective oxidation of saturated hydrocarbons at secondary positions

The selectivity in the oxidation of saturated hydrocarbons by oxygen in pyridine-acetic acid in presence of an iron catalyst and zinc is strongly dependant on the oxygenation of the reaction mixture; using air and slow stirring, it is possible to attack adamantane and trans-1,4-dimethylcyclohexane almost exclusively at the secondary positions.

Synthese d'un disaccharide, constituant naturel d'anthracyclines antibiotiques et antitumorales

Zusammenfassung The methyl glycoside of 2,3,6-trideoxy-3-dimethylamino-4-0-(2,6-dideoxy-α- L -lyxo-hexopyranosyl)- L -lyxo-hexopyranose, a disaccharide naturally occurring in anti-tumor anthracycline antibiotics, was prepared as well as the methyl and benzyl glycosides of the corresponding di-O-acetyl N-acetyl derivative.

Part 3. Triethylborane-air: a suitable initiator for intermolecular radical additions of S-2-oxoalkyl-thionocarbonates (S-xanthates) to olefins

Under carefully controlled conditions, the triethylborane-air combination proves to be an efficient radical initiator that allows intermolecular radical additions of S-2-oxoalkyl-thionocarbonates (S-xanthates) to olefins. Depending on both the structures of the xanthate and the olefin, the addition process can be achieved at room temperature or slightly higher.

GC-MS Study of Gif-Oxidation System. GC-MS Contribution to Elucidation of Gif-Oxidation Mechanism on the Formation of Bipyridines and Coupled Pyridines

Abstract The mechanism for the Gif system of selective oxidation of hydrocarbons has been studied using the GC-MS technique. Several observations reported here concerning bipyridines, pyridine-hydrocarbon coupling products and oxidation products themselves contribute to the elaboration of the proposed mechanism.