Asymmetric Arylation of 2,2,2-Trifluoroacetophenones Catalyzed by Chiral Electrostatically-Enhanced Phosphoric Acids
作者:Jie Ma、Steven R. Kass
DOI:10.1021/acs.orglett.8b00900
日期:2018.5.4
A series of highly reactive metal-free chiralphosphoricacids possessing positively charged phosphonium ion substituents are reported and have been applied to Friedel–Crafts alkylations of indoles and 2,2,2-trifluoromethyl aryl ketones. These catalysts are orders-of-magnitude more active and have similar or better enantioselectivities than their noncharged analogues. High tolerance to a range of substrates
An enantioselective hydroxyalkylation of indoles and 7‐azaindole with trifluoromethyl ketones was found to be effectively promoted under high‐pressure conditions with a low loading of Cinchona alkaloids (e.g., 1–3 mol% of cinchonidine). Chiral tertiary alcohols containing a trifluoromethyl group were obtained at 9 kbar with good yield and enantioselectivity up to 89%, whereas usually merely traces
Efficient Guanidine-Catalyzed Alkylation of Indoles with Fluoromethyl Ketones in the presence of Water
作者:Marco Bandini、Riccardo Sinisi
DOI:10.1021/ol9005079
日期:2009.5.21
A simple and efficient guanidine-catalyzed methodology for the direct preparation of trifluoromethyl-indolyl-phenylethanols in the presence of water is reported. This synthetically viable class of compounds is obtained in excellent yields (up to 98%) through Friedel-Crafts-type alkylation of indoles with aromatic fluoromethyl ketones. Exceptional reaction scope of indoles and alkylating agents is described.
Reaction of indoles with aromatic fluoromethyl ketones: an efficient synthesis of trifluoromethyl(indolyl)phenylmethanols using K<sub>2</sub>CO<sub>3</sub>/<i>n-</i>Bu<sub>4</sub>PBr in water
A new, mild and efficient protocol for the synthesis of trifluoromethyl(indolyl)phenylmethanols by the reaction of indoles with a variety of aromatic fluoromethyl ketones in the presence of K2CO3 (15 mol %) and n-Bu4PBr (15 mol %) in water. The desired products were obtained in good to excellent yields without requiring a column chromatographic purification. The reusability of the catalytic system