Friedel-Crafts acylation, with heteroaromatic compounds

The alkylaluminum halide-induced Friedel-Crafts acylation is a very general and synthetically useful reaction that allows the functionalization of unsaturated fatty compounds. Acylations were carried out with different acylating agents such as acyl chlorides, dicarboxylic acid dichlorides, cyclic anhydrides, unsaturated acyl chlorides, and aromatic and heteroaromatic carboxylic acid chlorides, yielding a large... 

Friedel-Crafts reaction of phosgene with heterocyclic aromatic compounds is also difficult to stop at the acid chloride stage. However, under selected conditions, heteroaromatics such as thiophene can be directly acylated to give thiophenecarbonyl chloride [Scheme T9] (Ref. 15) ... 

Friedel-Crafts chemistry at an asymmetric center generally proceeds with racemization, but the use of mesylates or chlorosul-fonates as leaving groups has resulted in alkylations with excellent control of stereochemistry. The reactions proceed with inversion of configuration (eq 3). Cyclopropane derivatives have been used as three-carbon units in acylation reactions (eq 4). In conjunction with triethy Isilane, a net alkylation is possible under acylation conditions (eq 5). These conditions are compatible with halogen atoms present elsewhere in the molecule. Acylation reactions of phenolic compounds with heteroaromatic systems have also been accomplished (eq 6). ... 

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