A perfect double role of CF3 groups in activating substrates and stabilizing adducts: the chiral Brønsted acid-catalyzed direct arylation of trifluoromethyl ketones
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