Halogenides, allyl

Benzyl- und Allyl-halogenide werden durch Lithiumalanat/Chrom(III)-, Vanadium(III)-, Titan(III)- und Wolfram(VI)-chlorid-Systeme zu substituicrten Athanen, geminate Dihalogenide zu substituierten Athylenen gekoppelt, vicinale Dibromide zu Alkenen debromiert8. 

It is prepared by reaction of phenoxyacetic acid alkali salts with allyl halogenide and used in technical perfumery. 

The terminal carhanionic sites of "living" polymers can be reacted with various electrophilic compounds of yield (o)-functional polymers. Esters, nitriles, acid chlorides, anhydrides, lactones, epoxides, benzyl or allyl halogenides have been used for their high reactivity with metal organic sites, to yield appropriate functions.2 Carbon dioxide is also an efficient reagent to yield terminal carboxylic functions. 

The observed difference for allyl halogenides in the reaction scheme indicated by isolation of organomercurials, involves a difference in the subsequent steps, not in the uptake of the first electron. 

Allylic halogenides containing an additional internal functional group in a suitable position, e. g., an alkene moiety or a hydroxy group, produce the corresponding cyclopentenone derivatives or lactones, respectively, via palladium-catalyzed carbonylation [43]. Related cyclocarbonylations of cinnamyl halides or acetates to form polycyclic aromatics such as naphthol derivatives have been reported (eq. (15)). Moreover, the synthetic utility of the method was demonstrated by the synthesis of acetoxybenzofurans, acetoxyindoles, and acetoxycarbazoles [44]. 

Tiefe Temperaturen sind bei Verwendung sek. Allyl-halogenide angebracht, um Kupp-lungsreaktionen zu unterdriicken298. 

A number of other allyl halogenide compounds [438] reacts analogously to allyl chloride, the yields being in the range of 70-80%. 

In analogy to allyl halogenides, iodobenzene and other aromatic iodo derivatives can be reacted with Ni(CO)4 and acetylene at reaction temperatures above 100 °C with formation of y-ketoacids or their esters [418, 442], which may be considered as hydrolysis products of p,y-unsaturated y-lac-tones or as hydrogenation products of a,p-unsaturated y-ketoacids or -esters. a,p-Unsaturated y-ketoacids or -esters will be hydrogenated under the reaction conditions, but do not take up carbon monoxide because of the presence of electrophilic substituents. Besides allyl halogenides, allyl alcohols, -ethers and -esters may also be reacted to give unsaturated acids or esters. 

Carbonium ions are formed by splitting off hydrogen halide from the allyl halides. Since primary and secondary allyl halogenides are less reactive, only tertiary alkyl halogenides may be converted in high yield. Thus, sec. butyl chloride yields only 30 % of 2-methyl butyric acid whereas tert. butyl chloride forms pivalic acid in 76 % yield. 

Allyl alcohol, CH2=CH-CH20H, is obtained from allyl chloride by alkaline hydrolysis. Oxydation of allyl alcohol gives acrolein, glycerol, formic acid, diallyl phthalate, acrylic acid. Allyl halogenids, allyl esters, allyl amines, allyl Grignard reagent can be obtained. End products are plastics, resins, plasticizers, varnish ingredients, pharmaceuticals, perfumes, flavors. 

Allyl-type monomers do not yield high polymers. The substituent on the carbon in the / position with respect to the double bond is easily eliminated (especially hydrogen, halogenides, etc.). The generated radical is resonance-stabilized. It reacts much more readily with growing radicals than with the monomer. The low probability of long chain formation is a consequence of these terminating and transfer reactions. 

Utilization of a selenium-initiated electrophilic cyclization (lactonization, etherification) in conjunction with a [2,3] sigmatropic selenoxide rearrangement provided a convenient, stereoselective access to highly substituted bicyclic lactones or ethers (entries 6-8)25-29. The electrophilic addition of phenylselenenyl halogenides to dienes can occur in a 1,2-(anti)-or 1,4-fashion furnishing allylic selenides in both cases. 

Under phase transfer conditions (boiling benzene, 50% aquous sodium hydroxide solution and tetia-n-butylammonium hydrogenphosphate) benzamides are monoalkylated. In the solid-liquid PTC system potassium hydride, tetrahydrofuran and 18-crown-6, acidic trifluoroacetamides are rapidly deprotonated and alkylated with lower kyl, allyl and benzyl halogenides in high yield. Methylation of trifluoroacetamides is carried out under less basic conditions in KOH/acetone. A similar reaction in KOH/DMSO generally allows the efficient reaction of benzamide and acetanilide with primary alkyl halides with secondary halides only moderate yields are accomplished, whereas tertiary halogenides are not alkylated due to dehydrohalogenation. ... 

Patzold, E. Ohme, G. (1993) Water-soluble palladium(ll) phosphine complexes as catalysts in the hydrodehalogenation of allyl and benzyl halogenides under biphasic and phase-transfer conditions, J. Prakt. Chem. - Chem. Ztg., 335,181-4. 

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