Friedel-Crafts reaction intramolecular aromatic

Several of the well known cyclization reactions of aromatics that are used for the preparation of benzoheterocycles also work for pyridines (66AHC(6)229). 3-Aminopyridine undergoes the Skraup reaction (equation 59), and the substituted 3-amino derivative (97) undergoes intramolecular Friedel-Crafts reaction (equation 60). Further examples of these reactions can be found in the appropriate part of Chapter 2.06. 

The dyes are synthesized either from A-alkylnaphtholactams, obtained by intramolecular Friedel-Crafts reaction of the 1-alkylnaphthylamine carboxylic acid chlorides, or by subsequent alkylation of the dye bases obtained by condensation of naphtholactam with aromatic amines [47],... 

H. Heaney, The Intramolecular Aromatic Friedel-Crafts Reaction, in Comprehensive Organic Synthesis (B. M. Trost, I. Fleming, Eds.), Vol. 2, 753, Pergamon Press, Oxford, 1991. 

Treatment of saturated azlactones with aromatic compounds under Friedel-Crafts conditions gives acylamino ketones in high yield (equation 46). 4-Benzyl-2-methyl-5(4H)-oxazolone undergoes an intramolecular reaction to yield an acetamidoindanone (equation 47). Friedel-Crafts reactions of 4-(arylmethylene)-5(4H)-oxazolones are complicated by the presence of an additional electrophilic centre (cf. 201) and may follow three courses. The unsaturated azlactone (189) adds benzene under the influence of aluminum chloride to form the saturated azlactone (207) in inert solvents (189) undergoes an intramolecular acylation to yield a mixture of the indenone (208) and the isoquinoline (209 Scheme 20). 

Other fused azepines, with aromatic (e.g. 94a,b) or heteroaromatic fused rings (e.g. 94c,d) have been prepared via the Af-acyliminium ion intermediate 93 in high yields lactam reduction then yielded the respective amines 95a,b and 95c,d [01H1519]. An intramolecular Friedel-Crafts reaction has been used to synthesise the fused azepinone 99 (S,S configuration) from 98, the latter being prepared from the diastereopure a-hydroxylactam 96, via the acid 97 [02H449],... 

Thio- and selenoacetals and esters are excellent substrates for mild Friedel-Crafts reactions, because of the affinity of sulfur and selenium for copper (Sch. 23). Anisole was readily acylated with methylselenoesters 94 at room temperature with activation by CuOTf to affordpnra-substituted (> 95 %) derivatives 95 [50,51]. Mercury(II) and copper(II) salts, which were effective for the activation of selenyl esters for reaction with alcohols, amines, and water, were not effective for the Friedel-Crafts reaction. Aromatic heterocycles 96 could be acylated in high yields, and the alkylation product 100 was obtained from dibutylthioacetal 99 and anisole. Vedejs has utilized this methodology in the cyclization of 101 to afford 102 in 77 % yield [52]. This intramolecular variant did not require the use of the more reactive bis copper triflate-benzene complex. 

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