Calcium‐Catalyzed Friedel–Crafts Alkylation at Room Temperature

Calcium‐Catalyzed Direct Coupling of Alcohols with Organosilanes

“…The addition of the allyl anion surrogate occurred regioselectively in the case of alcohols 4, 6, and 10 (Table 2, Entries 1, 3 and 4), and only product 9 was obtained as a 6.2:1 mixture of regioisomers 9a/9b (Table 2, Entry 3; Supporting Information). In analogy with previously investigated calciumcatalyzed reactions, [3,6] tertiary allylic alcohol 12 reacted with complete isomerization of the double bond to yield product 13. The allylation of secondary benzylic alcohols gave the desired products in good yields and selectivities (Table 2, Entries 6-9).…”

“…We recently reported a novel calcium-based, highly Lewis acidic catalyst system for the dehydration of benzylic, allylic, and propargylic alcohols and their subsequent reaction with nucleophilic arenes under very mild reaction conditions. [2,3] We have now turned our attention towards catalytic C-C bond formation with water-tolerant organometallic reagents. The general utility of unsaturated organosilicon compounds as carbanion surrogates is well recognized.…”

Friedel–Crafts Alkylation of Indoles Exclusively in Water Catalyzed by Ionic Liquid Supported on a Polyacrylonitrile Fiber: A Simple “Release and Catch” Catalyst

“…The search for new approaches for the alkylation products in good yields under mild conditions has attracted increasing interest. [6,7] Beyond that, the development of protocols to replace toxic alkyl halides with more benign alkylating agents is crucial to chemical technology and environmental concerns, [8,9] and it will also continue to influence and motivate the development of catalysts for environmental remediation. [10] One area in this field that has attracted much attention is the reaction of indoles to give their derivatives [11,12] such as bis(indolyl)methanes, which are more attractive active materials as bioactive metabolites of terrestrial and marine origin [13,14] and have wide medicinal applications in the pharmaceutical and agrochemical industries.…”

Alcohols in direct carbon-carbon and carbon-heteroatom bond-forming reactions: recent advances

“…84 Alkylation of electron-rich arenes using secondary and tertiary benzylic, allylic, and propargylic alcohols in the presence of calcium-based catalyst was described by Niggemann and Meel. 85 Reactions were performed under the optimized conditions (5 mol% Ca(NTf 2 ) 2 and 5 mol% Bu 4 NPF 6 , in DCM, at room temperature). A general and selective C-3 alkylation of indoles with primary alcohols in o-xylene catalyzed by reusable alumina-supported Pt nanocluster (Pt/θ-Al 2 O 3 -1.5 nm, 1 mol%) was reported.…”

“…92 Furthermore, alkylation of furans by benzyl, allyl, and propargyl alcohols 80,[93][94][95][96] in the presence of Lewis acids as a catalyst has been also reviewed 17 and of the many results a selection is shown in Table 11. The catalytic nucleophilic substitution of tertiary alcohols of type 15, using carbon or heteroatom based nucleophiles in the presence of Lewis acid has been the several publications 79,85,98,99 as well as a review 20 and selected results are shown in Table 12. Tables 13 and 14 respectively.…”