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
The effect of pressure (up to 10 kbar) on the Brønsted acid catalyzedenantioselective hydroxyalkylation of indoles with trifluoromethyl ketones was explored. The reaction was effectively accelerated at 9 kbar with a very low loading of a 1,1′‐bi‐2‐naphthol (BINOL) ‐derived phosphoric acid (0.05–0.2 mol % of TRIP) and provided the products with high enantioselectivity (84–98 % ee).
A perfect double role of CF3 groups in activating substrates and stabilizing adducts: the chiral Brønsted acid-catalyzed direct arylation of trifluoromethyl ketones
作者:Jing Nie、Guang-Wu Zhang、Lian Wang、Aiping Fu、Yan Zheng、Jun-An Ma
DOI:10.1039/b900474b
日期:——
A direct and efficient Brønsted acid-promoted arylation of tri- and difluoromethyl ketones, as well perfluoroalkyl ketones, has been developed; good to excellent enantioselectivities (up to 99% ee) were achieved.