Ir-catalyzed enantioselective addition of an N-methyl C–H bond of 2-(methylamino)pyridine derivatives to α-trifluoromethylstyrenes proceeded via C–Hactivation to give chiral γ-branched amine derivatives having a trifluoromethyl-substituted stereocenter. It was found that a bulky and electron-withdrawing group at the 3-position of 2-(methylamino)pyridines was necessary for the present C–H addition reaction
N‐Heterocyclic Carbene Catalyzed Photoenolization/Diels–Alder Reaction of Acid Fluorides
作者:Andreas Mavroskoufis、Keerthana Rajes、Paul Golz、Arush Agrawal、Vincent Ruß、Jan P. Götze、Matthew N. Hopkinson
DOI:10.1002/anie.201914456
日期:2020.2.17
aromatic aldehydes and ketones. Stoichiometric studies and TD‐DFT calculations support a mechanism involving the photoactivation of an ortho‐toluoyl azolium intermediate, which exhibits “ketone‐like” photochemical reactivity under UVA irradiation. Using this photo‐NHC catalysis approach, a novel photoenolization/Diels–Alder (PEDA) process was developed that leads to diverse isochroman‐1‐one derivatives
Highly Enantioselective Construction of Trifluoromethylated All-Carbon Quaternary Stereocenters via Nickel-Catalyzed Friedel–Crafts Alkylation Reaction
A highlyenantioselectiveFriedel-Craftsalkylation reaction of indoles with β-CF(3)-β-disubstituted nitroalkenes was achieved using a Ni(ClO(4))(2)-bisoxazoline complex as a catalyst, which afforded indole-bearing chiral compounds with trifluoromethylated all-carbon quaternary stereocenters in good yields with excellent enantioselectivities (up to 97% ee). The transformation of one of the products
A Pd-catalyzed [3+2] cycloaddition reaction of vinylcyclopropane and trifluoromethyl ketones as well as α-keto esters were developed, affording tetrahydrofurans in high yield.
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