Friedel-Crafts alkylation allylic acylation

The scope of Friedel-Crafts chemistry has been expanded beyond aromatic systems to nonaromatic systems, such as alkenes and alkynes and the mechanistic details have been investigated. The Friedel-Crafts alkylation and acylation of alkenes provide access to a variety of organic systems (eq 9). The acylation of alkynes provides access to cyclopentenone derivatives (eq 10). In addition, one can use this chemistry to access indenyl systems and vinyl chlorides. AllyUc suHones can undergo allylation chemistry (eq 11). ... 

Removal of the one- carbon electrophilic formaldehyde (cf p T 10) leaves a chlorophenol (7) made by direct chlorination of (8). The long allyl chain of (8) cannot be put in by Friedel-Crafts alkylation or rearrangement will occur Cp T 9) so acylation and reduction are preferred. 

EtAlCb catalyzes the Friedel-Crafts acylation of alkenes with acid chlorides, the formal [3 + 2] cycloaddition of alkenes with cyclopropane-1,1-dicarboxylates (eq 21), the Friedel-Crafts alkylation of anilines and indoles with ct-aminoacrylate esters, and the formation of allyl sulfoxides from sulfinyl chlorides and alkenes. EtAlCU induces the Beckmann rearrangement of oxime sulfonates. The cationic intermediates can be trapped with enol silyl ethers (eq 22). EtAlC is the preferred catalyst for addition of the cation derived from an a-chloro sulfide to an alkene to give a cation which undergoes a Friedel-Crafts alkylation (eq 23). ... 

Many organic chemical transformations have been carried out in ionic hquids hydrogenation [4, 5], oxidation [6], epoxidation [7], and hydroformylation [8] reactions, for example. In addition to these processes, numerous synthetic routes involve a carbon-carbon (C-C) bond-forming step. As a result, many C-C bondforming procedures have been studied in ambient-temperature ionic Hquids. Among those reported are the Friedel-Crafts acylation [9] and alkylation [10] reactions, allylation reactions [11, 12], the Diels-Alder reaction [13], the Heck reaction [14], and the Suzuki [15] and Trost-Tsuji coupHng [16] reactions. 

Despite the lack of examples of Friedel-Crafts acylations catalyzed by Lewis acids, - reactions of stannanes with acyl halides catalyzed by palladium species have found considerable use for the preparation of ketones. Since alkyl groups are only transferred slowly from tin, more rapid transfer to the acyl chloride is observed for alkynyl, alkenyl and allyl, as well as aryl and benzyl, groups. This leads to a versatile synthesis of ketones.Acylations of alkenylstannanes are both regio- and stereo-specific. 

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