Friedel-Crafts method

This is the infamous Friedel-Crafts method and works in a manner similar to the previously mentioned method where P2P was made by merging benzene and chloroacetone using AICI3. This method is for speed makers only and is not recommended for conversion of 1,3-benzodioxole. However, this should work in a limited way on catechol. The conversion factor is very low but that isn t a major concern of speed chemists because cheap old benzene is the precursor and all of that benzene that isn t converted can be run back through this simple little process over and over again. Before she knows it, the chemist will have amassed an enormous amount of allylbenzene [139, 140]. 

There are a great many aspects to the Friedel-Crafts method that Strike does not have the space to go into. Friedel-Crafts works better if chloro or bromobenzene and their X counterparts are used in place of plain old benzene. Also, there is a significant amount of unwanted byproducts and molecular rearrangements that accompany this sort of reaction. Strike strongly suggests that people read more about this method before they attempt any such reaction. 

This is similar to the Friedel-Crafts method but is less harsh and has been proven successful at producing safrole. In a very small flask is added 7.2g of allyl chloride, 34.3g 1,3-benzodioxole and 0.15g powdered Cu (which can be made by... 

It has also been stated that the 5-position of selenazoles is more reactive toward electrophilic substitution than that of thiazoles. Such reactivity is still further increased by substituents in the 2-position of the selenazole ring, which can have an —E-effect. Simultaneously, however, an increasing tendency toward ring fission was observed by Haginiwa. Reactions of the selenazole ring are thus limited mainly to the 5-position which, specially in the 2-amino-and the 2-hydrazino-selenazoles, is easily substituted by electrophilic reagents. However, all attempts to synthesize selenazole derivatives by the Gattermann and by the Friedel-Crafts methods... 

Dihydroxyacetophenone (II) can be prepared in good yield by heating hydroquinone diacetate (I) in the presence of 3 -3 mols of aluminium chloride, Hydroquinone cannot be acylated by the Friedel-Crafts method. 

In this way aromatic carboxylic acids can he prepared by the Friedel-Crafts method. 

Fischer and Hafner reported an alternate synthesis of bis-ir-benzene chromium using a reductive Friedel-Crafts method which probably also proceeds via a [Pg.231]

The catalysts or condensing agents which have been employed most frequently for intramolecular acylation by the Friedel-Crafts method are aluminum chloride and the less active stannic chloride. Mention of the use of the intermediately active ferric chloride may be found,12 but the generality of this procedure has not been demonstrated. 

Comparison op Yields with Aluminum and Stannic Chloride in the Friedel-Crafts Method... 

Comparison op Yields Obtained bt the Sulfuric Acid and Friedel-Crafts Methods... 

Stannic Chloride pn the Free Acid. Ring closure by heating the free acid with stannic chloride at 100-120° has been shown to be successful on several types of acids.85 47> 8 88 80, 189 819 These and some other acids which have been cyclized by this method may be found in Table XI. In four instances (items 3, 7, 14, 17) stannic chloride treatment gave better results than sulfuric acid. Eleven of the acids in Table XI (items 3, 5, 8, 9, 10,12, 13, 14, 16, 17, 18) have been cyclized also by the Friedel-Crafts method on the acid chloride. With seven acids (3, 6, 8, 9, 12, 14, 17) the yields were better, while with four (5, 10, 16, 18) they were lower, than with stannic chloride. Except for one (18) of these latter acids, however, there seems to be some question as to whether the optimum conditions for the Friedel-Crafts reaction were employed. Of the acids (4, 6,12) which have since been cyclized with hydrogen fluoride, considerable improvement in yields was realized. 

C. C. Price, The Alkylation of Aromatic Compounds by the Friedel—Crafts Method, Org. React. 1946, 3, 1-82. 

The isolation from the Grignard glucosylation of benzene of a product identical with that obtained by the Friedel-Crafts method made it apparent that no intramolecular isomerizations or inversions accompanied the latter process, and that products such as IV and V indeed... 

By using the Friedel - Crafts method, 26.5 grams of allqd benzene is produced from 0.25 mol of benzene. Determine the structure of the produced benzene derivative. 

Diketones have been prepared by the Friedel-Crafts method. Both acyl chloride groups in adipyl chloride react with benzene in the presence of aluminum chloride to form the diketo compound, 1,4-dibenzoylbutane (81%). When diketene is treated with benzene under the conditions of the Friedel-Crafts reaction, benzoylacetone, COCHjCOCH, is formed... 

The Friedel-Crafts method is the most versatile route available for preparing arene-metal complexes, having been applied successfully to nearly a dozen transition metals. The method has definite limitations, however, with regard to the type of arene unit used, and only alkyl- and aryl-substituted benzenes in general can be successfully employed. 

One rather interesting aspect of the Friedel-Crafts reaction is that trialkylation of benzene often leads to a symmetrical 1,3,5-isomer rather than a 1,2,4-derivative as would be expected from the ortho-para orientation of the alkyl group introduced initially. Since alkylation by the Friedel-Crafts method has been shown to be a reversible reaction,68 this anomalous orientation has been explained on the basis that both alkylation and dealkylation occur readily in the ortho and para positions. Simultaneously, however, some alkylation occurs in the meta position but no dealkylation68 If the reaction mixture is allowed to stand in contact with aluminum chloride for some length of time, then principally meta trialkyl derivatives will be formed ... 

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