Arenes cycloalkylation

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... 

The direct functionalization of arenes by primary alcohol sulfonate esters has also been reported.44 5mol% AUCI3/AgOTf was again used as catalyst and high yields (up to 92%) of products obtained in some cases. Higher yields (e.g. 97, 93%) were obtained in intramolecular cycloalkylation reactions of a similar type. 

Alkylation of arenes with cycloalkenes (cycloalkylation) is also well documented in the literature. A variety of Lewis and Brpnsted acids have been us as catalysts for these reactions. These reactions share many similarities with the alkylation reactions of arenes with other alkylating agents such as al-kenes. The selectivity of the cycloalkylation reaction depends upon the conditions and catalyst. A few examples of cycloalkylation reactions are presented in equations (44) to (46). - ... 

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. 

Later, He and coworkers developed a new gold(III)-catalyzed stereospecific cycloalkylation of electron-rich arenes with tethered epoxides 23, which provided a rapid access to 3-chromanols 24 (Scheme 12.11) [15]. The proposed reaction mechanism proceeds through C-H activation of the arene, followed by addition to the tethered epoxide (path A) however, a second possible mechanism in which... 

Scheme 1.18 Proposed mechanism for the ruthenium-catalyzed cycloalkylation of arenes via CDC.

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