Barbier

Barbier-Wieland degradation A method for the stepwise degradation of aliphatic acids... 

Barbier reported (1) in 1899 that a mixture of methyl iodide, a methyl ketone, and magnesium metal in diethyl ether produced a tertiary alcohol. Detailed studies by his student Victor Grignard are documented in his now classical doctoral thesis, presented in 1901. Grignard estabUshed (2) that the reaction observed by Barbier could be separated into three distinct steps Grignard reagent formation, Grignard reaction, and hydrolysis. 

BARBIER - WIELAND Degradation A multi-step procedure tor chain degradation ot esters... 

Proceedings of the 3rd International Symposium, Poitiers, April 5-8,1993 edited by M. Guisnet, J. Barbier, J. Barrault, C. Bouchoule, D. Duprez,... 

The processes used in the manufacture of morphine are believed to be still based on that described by the Scottish chemist Gregory,in 1833, with improvements devised by Anderson. A description has been published by Schwyzer, who also deals with the manufactme of codeine, narcotine, cotarnine, and the commercially important morphine derivatives, diamorphine (diacetylmorphine), and ethylmorphine (morphine ethyl ether). More recently Barbier has given an account of processes, based on long experience in the preparation of alkaloids from opium. Kanewskaja has described a process for morphine, narcotine, codeine, thebaine and papaverine, and the same bases are dealt with by Chemnitius, with the addition of narceine, by Busse and Busse, and by Dott. It is of interest to note that a number of processes for the extraction and separation of opium alkaloids have been protected by patent in Soviet Russia. ... 

Perfluorovinyl organotin compounds can be prepared from perfluorovinyl Grignard reagents and organotin halides [76] (equation 11) Yields are slightly improved under Barbier conditions [76]... 

Under Barbier conditions, trifluoromethyl bromide reacts with electrophiles, such as aldehydes, Orkelo esters, activated esters, and anhydrides in the presence of pyridine to give trifluoromethylated compounds [35, 45 46] (equations 34 37)... 

Barbier conditions have been used to carry out a silicon-induced addition of perfluoroalkyl iodides to DMF to give stable hemiaminal intermediates, which give the perfluonnated aldehydes upon heating with sulfuric acid [47 (equation 38)... 

In a separate report, preparation of the lithium enolate of 31 in the presence of indium trichloride and benzaldehyde provided a 77% yield of 32 with complete trans selectivity however, sequential addition of indium trichloride and benzaldehyde provided Barbier-type products. Organotin enolates have also been used in a Darzens-type... 

Semmler Isolated the characteristic component of this oil, wkueh be termed coriandtol, an alcohol of tbe formula Barbier ... 

There appear-to be either several isomerides of pinonic acid, or such closely related oxidation products as to render the purification of the acid a matter of great difiiculty. The characters of the dextro- and laevo-rotatory forms of this acid have, ho t ever, been settled by the researches of Barbier and Grignard and himmel Co, ... 

By oxidation of d- and Z-pinene of high rotatory power, Barbier and Grignard obtained the optically active forms of pinonic acid. Z-pinene from French turpentine oil (boiling-point 155 to 157 , od - 37 2 157 to 160 , tto - 32 3°) was oxidised with permanganate. From the product of oxidation, which (after elimination of the volatile acids and of nopinic acid) boiled at 189 to 195 under 18 mm. pressure, Z-pinonic acid separated out in long crystalline needles, which, after recrystallisation from a mixture of ether and petroleum ether, melted at 67° to 69 . The acid was easily soluble in water and ether, fairly soluble in chloroform, and almost insoluble in petroleum ether. Its specific rotation is [a]o - 90-5 in chloroform solution. Oximation produced two oximes one, laevo-rotatory, melting-point 128 and the other, dextro-rotatory, melting-point 189° to 191°. 

The last of these bodies announced as being alcoholic constituents of rose and geranium oils was reuniol, found in various geranium oils (BAunion, African, and Spanish) by A. Hesse. This had previously been announced as a probable chemical individual by Barbier, but he stated that he had not obtained it pure. Erdmann and Huth claimed that it was more or less pure rhodinol. 

There seems, however, to-day, to be overwhelming evidence that the French chemists were correct and that citronellol and rhodinol are two very similar, but chemically different, compounds, citronellol being represented by the formula (1) and rhodinol by formula (2). Considerable evidence of this is to be found in the work of Barbier and Locquin. Starting from the acetic esters of ordinary d-citronellol and rhodinol from oil of geranium or rose, they attached hydrogen chloride to the double bond, and obtained the same additive product according to the equations — ... 

Barbier and Bouveault,i however, assigned to it the unlikely formula—... 

The mechanism for the transformation of 5 to 4 was not addressed. However, it seems plausible that samarium diiodide accomplishes a reduction of the carbon-chlorine bond to give a transient, resonance-stabilized carbon radical which then adds to a Smni-activated ketone carbonyl or combines with a ketyl radical. Although some intramolecular samarium(n)-promoted Barbier reactions do appear to proceed through the intermediacy of an organo-samarium intermediate (i.e. a Smm carbanion),10 ibis probable that a -elimination pathway would lead to a rapid destruction of intermediate 5 if such a species were formed in this reaction. Nevertheless, the facile transformation of intermediate 5 to 4, attended by the formation of the strained four-membered ring of paeoniflorigenin, constitutes a very elegant example of an intramolecular samarium-mediated Barbier reaction. 

The Barbier-type modification17, in which the allyl Grignard reagent is produced in the presence of a carbonyl compound, seems not to be suitable for enolizable aldehydes. Some... 

Usually, in situ preparation in Barbier-type carbonyl additions are carried out with the bromides or chlorides even sterically blocked carboxylates, such as 2,4,6-trimethylbenzoic acid esters, can be used successfully15. The reactions are accelerated by ultrasound16,17. 

Similar reactions were also carried out with 3-bromopropene, l-bromo-2-butene, 3-bromocy-clohcxcnc. and 3-bromocyclooctene in refluxing ethanol as solvent24 . Zinc-mediated Barbier reactions can be accomplished with high yields in a mixture of saturated aqueous NH4C1/THF (5 1), at room temperature or below using a 1.2 to 2-fold excess of the halide over the carbonyl compound25. 

Mossbauer spectroscopy of mono-organotin(IV) derivatives. R. Barbier, L. Pellerito, N. Bertazzi and G. C. Stocco, Inorg. Chim. Acta, 1974,11,173-183 (66). 

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