Fast, highly enantioselective, and sustainable fluorination of 4-substituted pyrazolones catalyzed by amide-based phase-transfer catalysts

Abstract

We developed an amide-based Cinchona alkaloids catalyzed enantioselective fluorination of 4-substituted pyrazolones, the products with a quaternary chiral fluorine-attached carbon centre were afforded in high yields (up to 99%) with...

Enantioselective α-Trifluoromethylthiolation of Carbonyl Compounds with AgSCF3 and Trichloroisocyanuric Acid

“…Great efforts in asymmetric synthesis of chiral pyrazolone and its derivatives have been made in recent years . Furthermore, the enantioselective introduction of a heteroatom at the C-4 position has also attracted large amounts of attention from organic chemists because of the importance of heteroatoms in medicinal chemistry . However, there is only one enantioselective approach for the synthesis of chiral SCF 3 substituted pyrazolone skeleton as far as we know .…”

Light-mediated catalytic enantioselective difluoroalkylation of β-ketoesters via phase-transfer catalysis

“…45 These organocatalysts have enjoyed broad appli-cations with a range of substrates, including with β-ketoesters. [46][47][48] The biphenyl amide was appended to the four common cinchona alkaloids to give catalysts C18-21. These all eclipsed PTC C1 giving the highest yields of enantioenriched product 3a seen thus far (Table 2, entries 1 vs. 18-21).…”

A New 2-Aminospiropyrazolylammonium Cation with Possible Uses in the Topical Areas of Ionic Liquids

“…In contrast to chiral cation-based PTCs, which mainly operate through the coordination and control of the nucleophile, these anionic PTCs usually coordinate cationic (and often hardly soluble) electrophilic reagents. This complementary strategy has also been rather impressively used for different asymmetric heterofunctionalization reactions [159,160].…”