Organic synthesis Friedel-Crafts reactions

Dysprosium(III) catalysis in organic synthesis (Friedel—Crafts alkylation, Mannich-type, Diels—Alder, and Povarov reactions) 12T2015. Enamides and related functional groups as nucleophihc components in ring-forming processes catalyzed by electrophihc metal salts 12SL814. 

Stamatoff and Wittmann reported a synthesis of a 2-(4-phenoxyphenyl)hexa-duoroisopropanol in the presence of HF and an organic solvent via a Friedel-Crafts reaction, as shown in Scheme 6.29.231 The resulting polymer could be compression molded at 330-350°C. It also exhibited excellent thermostability and mechanical properties. 

Among the wide variety of organic reactions in which zeolites have been employed as catalysts, may be emphasized the transformations of aromatic hydrocarbons of importance in petrochemistry, and in the synthesis of intermediates for pharmaceutical or fragrance products.5 In particular, Friede 1-Crafts acylation and alkylation over zeolites have been widely used for the synthesis of fine chemicals.6 Insights into the mechanism of aromatic acylation over zeolites have been disclosed.7 The production of ethylbenzene from benzene and ethylene, catalyzed by HZSM-5 zeolite and developed by the Mobil-Badger Company, was the first commercialized industrial process for aromatic alkylation over zeolites.8 Other typical examples of zeolite-mediated Friedel-Crafts reactions are the regioselective formation of p-xylene by alkylation of toluene with methanol over HZSM-5,9 or the regioselective p-acylation of toluene with acetic anhydride over HBEA zeolites.10 In both transformations, the p-isomers are obtained in nearly quantitative yield. 

The Friedel-Crafts reaction is one of the most important and versatile tools for the formation of carbon-carbon bonds in the synthesis of substituted aromatic and heteroaromatic compounds present in numerous natural products and drugs. Catalytic asymmetric variants using either metal complexes or organic molecules attracted considerable attention over the last few years. 

Heaney H (1991) The bimolecular aromatic Friedel-Crafts reaction. In Trost BM, Fleming I (eds) Comprehensive organic synthesis, vol 2. Pergamon, Oxford, p 733... 

S. C. Eyley, The Aliphatic Friedel-Crafts Reaction, in Comprehensive Organic Synthesis (B. M. Trost, I. Fleming, Eds.), Vol. 2, 707, Pergamon Press, Oxford, 1991. 

Regarding acylation reactions, acylation of alcohols produces esters and acylation of amines produces amides Both of these transformations are illustrated in Figure 8.2. These, in addition to the introduction of acyl groups adjacent to carbonyls (Scheme 8.11), only hint at the breadth of related acylation reactions available and useful in organic synthesis. One additional reaction is the Friedel-Crafts acylation illustrated in Scheme 8.12. Through this transformation, extended functionalization of aryl groups becomes accessible. 

Introduction. The object of this and of the two following experiments is to illustrate the application of the Friedel-Crafts reaction to the synthesis of organic compounds. In the present experiment the preparation of aromatic hydrocarbons will be considered. 

The Friedel-Crafts reaction and the related Fries rearrangement of aromatics are the most important methods in organic chemistry for synthesizing aromatic ketones, which are of interest in the synthesis of numerous fine chemicals such as drugs, fragrances, dyes and pesticides. 

Especially, the eco-friendly ionic liquids have obtained extensive attention in organic synthesis with the merits provided as above. The ionic liquids as the unusual green solvents are applied extensively in various organic synthesis reactions, such as Friedel-Crafts reactions, oxidation reactions, reduction reactions, addition reactions, C-C formation reactions, nucleophilic substitution reactions, esterifications, rearrangements, hydroformylations, and nitration reactions [7-14]. Besides, the ionic liquids also have applications in the extraction separation, the electrochemistry, and preparation of nanostructured materials, the production of clean fuel, environmental science, and biocatalysis. This chapter would present in detail the application of the ionic liquids as the unusual green solvents (also as dual green solvent and catalyst) for the alkylation and acylation. 

Ionic liquids have numerous applications in organic synthesis. Some of the important reactions have proved that ionic liquids are truly versatile catalysts. Reaction media include, esterification reaction [67, 68], aldol condensation [69, 70], hydrogenation [71], Friedel-Crafts reactions [72,73], oxidation [74-76], Henry reaction, cross-coupling reactions [77,78], and some enzyme reactions [79, 80]. 

The primary use of nitrobenzene is in the captive production of aniline, with about 97.5% of nitrobenzene production consumed in this process. The major use of aniline is in the manufacture of polyurethanes. Nitrobenzene is also used as a solvent in petroleum refining, in the manufacture of cellulose ethers and acetate, and in Friedel-Crafts reactions to hold the catalyst in solution. It is also used in the synthesis of other organic compounds including acetaminophen, which is an over-the-counter analgesic commonly known as Tylenol . 

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