Lactones arene alkylation

Lactones, via indium compounds, 9, 686 Lactonizations, via ruthenium catalysts, 10, 160 Ladder polysilanes, preparation and properties, 3, 639 Lanthanacarboranes, synthesis, 3, 249 Lanthanide complexes with alkenyls, 4, 17 with alkyls, 4, 7 with alkynyls, 4, 17 with allyls, 4, 19 with arenes, 4, 119, 4, 118 and aromatic C-F bond activation, 1, 738 bis(Cp ), 4, 73... 

Heterobimetallic homogeneous catalysts [e.g. (12)] have been developed26 for the alkylation of a range of aromatic compounds by n-activated alcohols. The superior electrophilicity is attributed to the high-valent T-Sn core in the structures. A review has appeared of reactions involving the hydroxyalkylation and cycloalkylation of arenes by hydrofurans, lactones, and unsaturated acids 27... 

All types of electrophiles have been used with 2-lithio-l,3-dithiane derivatives, including alkyl halides, sulfonates, sulfates, allylic alcohols, arene-metal complexes, epoxides, aziridines, carbonyl compounds, imines, Michael-acceptors, carbon dioxide, acyl chlorides, esters and lactones, amides, nitriles, isocyanates, disulfides and chlorotrialkylsilanes or stannanes. The final deprotection of the dithioacetal moiety can be carried out by means of different types of reagents in order to regenerate the carbonyl group by heavy metal coordination, alkylation and oxidation184 or it can be reduced to a methylene group with Raney-nickel, sodium or LiAIII4. 

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... 

The Friedel-Crafts alkylation of arenes with lactones provides a convenient method for the synthesis of arylalkanoic acids. However, depending on the nature of the arene, catalyst, temperature and reaction time, the resulting arylalkanoic acids can undergo partial or complete cyclization to the corresponding cyclic ketones (Scheme 10). Equations (65) to (68) show examples of Friedel-Crafts alkylations using lactones as the alkylating agents." "" ... 

As pointed out earlier, cycloalkylation reactions can also result from the reaction of arenes with bifunctional alkylating agents or in cases where bifunctional intermediates are involved. An example of the former is shown in equation (114), where a chiral, lactone-substituted alkene cyclizes with the arene to produce a chiral tetrahydronaphthalene derivative. 

Triethylsilane in trifluoroacetic acid has proved to be a mild and selective reducing agent for the conversion of aryl and diaryl ketones into the corresponding arenes however, with activated benzaldehydes, e.g, 4-MeCeH4-CHO, Friedel-Crafts alkylation competes with reduction. Reduction of phenyl cyclobutyl ketone and phenyl cyclopropyl ketone gives low yields (36 and ca. 25%, respectively) of the corresponding benzylcycloalkanes [the former reaction also affords phenylcydo-pentane (ca. 42%) via ring-expansion] and with ortAo-benzoylbenzoic acid and 3-benzoyIpropanoic acid the lactones (11) (100%) and (12) (86%), respectively, are formed. ... 

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