Direct trifluoroacetylation of indoles with ethyltrifluoropyruvate as a trifluoroacetylating reagent has been developed. This novel protocol provides an attractive route for the preparation of 3-trifluoroacetylindole derivatives, due to its operational simplicity and practicability as well as mild reaction conditions.
Weak Directing Group Steered Formal Oxidative [2+2+2]-Cyclization for Selective Benzannulation of Indoles
作者:Kiran R. Bettadapur、Raja Kapanaiah、Veeranjaneyulu Lanke、Kandikere Ramaiah Prabhu
DOI:10.1021/acs.joc.7b02719
日期:2018.2.16
A double C–H activation and double insertion process to achieve the synthesis benzo[e]indole frameworks has been disclosed. This type of benzannulation is directed by a trifluoromethylketone moiety, which is easy to install on the indole C3-position. Overall the reaction takes places as an oxidative cyclization of two alkynes with the C4–C5 position of indole.
Electronic Nature of Ketone Directing Group as a Key To Control C-2 vs C-4 Alkenylation of Indoles
作者:Veeranjaneyulu Lanke、Kiran R. Bettadapur、Kandikere Ramaiah Prabhu
DOI:10.1021/acs.orglett.6b02698
日期:2016.11.4
A novel mode of achieving site selectivity between C-2 and C-4 positions in the indole framework by altering the property of the ketone directing group is disclosed. Methyl ketone, as directing group, furnishes exclusively C-2 alkenylated product, whereas trifluoromethyl ketone changes the selectivity to C-4, indicating that the electronic nature of the directing group controls the unusual choice between
Rhodium(<scp>iii</scp>)-catalyzed C–H activation at the C4-position of indole: switchable hydroarylation and oxidative Heck-type reactions of maleimides
leading to novel and switchable functionalization has been reported by employing a weakly co-ordinating COCF3 group as a directing group. An additive plays an important role in switching the selectivity between 1,4-additionproducts and Heck-type products. An acid additive led to the formation of 1,4-additionproducts whereas a base additive promotes the formation of Heck-type products. Deuteration
An efficient and general reductive heteroarylation approach toward the synthesis of bisindolylmethane, bispyrrolylmethane, and indolylpyrrolylmethane derivatives has been developed. Thus, treatment of acylpyrrole or acylindole derivatives with indoles or pyrroles in the presence of a combination of sodium borohydride and acetic acid resulted in the formation of the title compounds in moderate to excellent