Cycloalkylation Friedel-Crafts reaction

Similarly, arylalkylamides, haloalkylarylamines, haloalkylaryl ketones and haloalkyl ethers undergo Friedel-Crafts cycloalkylation to give six- or five-mem red ring closure products. Representative examples of these reactions are shown in equations (99) to (103). " An excellent review by Brad-sher on the cycloalkylation of aiylcarbonyl compounds is available. 

The enol acetate (122) provided a model system for investigating some of the problems associated with the synthesis of alnusenone. Saponification and introduction of a methylene group gave the olefin (124). The latter and the two related epimeric tertiary alcohols provided useful substrates for examining the stereochemistry of the Friedel-Crafts cycloalkylation reaction. Polyphosphoric acid yielded the same mixture in each case, the major product being the compound (125) with the desired stereochemistry. The mechanistic details of this reaction are considered at length. 

A Co2(CO)6 -alkyne moiety has been used as a stereocontrol element in Friedel-Crafts cycloalkylation reactions that deliver ci5-4a-ethynyl-l,2,3,4,4a,9,10,10a-octahydrophenanthrenes exclusively. Intra- and intermolecular coupling reactions of Co2(CO)6 -complexed propargyl radicals have been reported to afford cyclic and acyclic 1,5-alkadiynes. 

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