Silica Sulfuric Acid–Catalyzed Friedel–Crafts Alkylation of Indoles with Nitro Olefins

Facile Iodine-Catalyzed Michael Addition of Indoles to α,α′-Bis(arylmethylene)cyclopentanones: An Efficient Synthesis of E-2-(3-Indolylphenylmethyl)-5-phenylmethylenec

“…Indole is a very good Michael donor through its 3-position, and the 3-indolyl system is one of the important building blocks for many biologically active compounds, both natural and unnatural [3]. Traditionally, the Michael addition of indole to α , β -unsaturated ketones as well as addition reactions of indole to other electron deficient olefins is known to be catalyzed by strong bases and Bronsted acids [4–8]. In recent years, it has been reported that these reactions can also be promoted by Lewis acids [9–20].…”

An efficient synthesis of 3-diethoxyphosphoryl-4-(1H-indol-3-yl)-3,4-dihydrocoumarins: a convenient approach to 3-methylene-4-(indol-3-yl)-3,4-dihydrocoumarins

“…Among several reactions of indole, the reactions involving C-3 functionalization of indole with electron-deficient olefins have attracted and continue to attract interest from the synthetic community. While the reaction of indoles with highly electrophilic nitroolefins and enones to furnish β-(indol-3-yl) alkylated products has been widely investigated, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] analogous reactions involving α,β-unsaturated esters to form 3-(indol-3-yl) alkanoates are rare. To date, two general strategies for the non-enantioselective synthesis of 3-(indol-3-yl) alkanoates have been reported.…”