Friedel-Crafts alkylation with epoxides

The alkylations of arenes by alcohols, ethers and esters, as well as with epoxides and lactones, are of considerable interest, and constitute a significant part of the field of Friedel-Crafts alkylations. Some of the earliest examples are the alkylations of arenes with primary alcohols, esters and ethers. < Subsequent work over the years has revealed that these alkylations are often accompanied by various side... 

Friedel—Crafts alkylation. Alkenes (styrenes and trisuhstituted alkenes) alkylate indoles at the 3-position in CH2CI2 containing 5 mol% of TfOH (or an Au(III) species). Benzyl trifluoromethyl carhinols are obtained from reaction of arenes with trifluoro-methyl epoxides. The direction of epoxide ring opening is determined by the electron-withdrawing trifluoromethyl group. ... 

ILs may themselves also act as catalyst. For heterogeneous catalysis, the IL has to be immobilized, for example, by covalent bonds on a porous support, as shown by Hoelderich et al. [40] for Friedel-Crafts alkylation reactions. Further examples of reactions tested with grafted ILs are acetylization [41], cycloaddition of CO2 [42, 43], and epoxidation of olefines [44]. 

Hoseini-Sarvari M and Parhizgar G. Regioselective Friedel-Crafts alkylation of indoles with epoxides using nano MgO. Green Chem. Lett. Rev. 2012 5(3) 439-449. 

The indirect propylene oxidation process via ethylbenzene hydroperoxide (Halcon process) is displayed in Eq. (6.12.12). Ethylbenzene, obtained by the acid-catalyzed Friedel-Crafts alkylation of benzene with ethylene, is converted with air into ethylbenzene hydroperoxide. The hydroperoxide epoxidizes propylene and generates the co-product a-phenylethanol that is later dehydrated to styrene. Styrene is a major industrial chemical used mainly as monomer for polymers such as polystyrene or styrene-containing copolymers ... 

Friedel-Craft Alkylation. St)rene epoxides can be opened efficiently at the benzylic position when treated with lithium perchlorate to provide the desired alcohol in 95% yield (eq 5). ... 

Alkylation Reactions of Indole Friedel-Crafts alkylation of indoles and pyrroles with epoxides has been efficiently carried out over three-dimensional (3D) mesoporous aluminosilicates catalysts (AlKlT-5) in water at room temperature (Scheme 19) [88]. The autiiors found that mesoporous silica materials containing an interconnected large-pore cage-type mesoporous system with 3D porous networks supposed to be more valuable than porous materials containing a hexagonal pore structure with a one-dimensional array of pores. 

Thioacetals eliminate to vinylsulfides in the presence of CuOTf (Scheme 46).192 Cu1 and Cu11 triflates are mild Lewis acids for Friedel-Crafts acylation and alkylation reactions. CuOTf effectively catalyzes the reaction of anisole with selenoesters.193,194 Copper(II) sulfate promotes epoxide ring opening reactions in the presence of pyridine,195 with retention of configuration being observed. Cu(OTf)2 is a catalyst for the ring opening of aziridine by aniline.196... 

Acetylenes are also reported to undergo intramolecular Friedel-Crafts-like alkylation as shown in Eq. (204) [489]. The reaction occurred regioselectively with respect to both epoxide and acetylene moieties and this was rationalized by the chelation structure involving the titanium metal as depicted. The facile preparation of a func-... 

Indium(III) chloride. 19,173-174 Isomerization of epoxides. Th< conversion of epoxides to carbonyl cot Reductive Friedel-Crafts alkylatit InClj-catalyzed alkylation with aldehy chlorodimethylsilane). The latter proce Aldol reactions. The Mukaiyan in water... 

A single-step benzoylation-oximation has been described on 4-hydroxy-coumarin by the use of PhCCl=NOH and EtjN in boiling methanol. When 7-methoxy-8-prenylcoumarin (osthol) or its epoxide was treated with various Lewis acids, several products were obtained. These resulted from migration or disappearance of the exocyclic double bond, abnormal Friedel-Crafts phenyl-ation, hydration, cyclization, or demethylation. A novel ring-opening of coumarins was effected by treatment with alkyl halides and NaH in THF. The c/5-o-alkoxycinnamic acid was obtained mainly or exclusively. 

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