Base initiated aromatization/C O bond formation: a new entry to O-pyrazole polyfluoroarylated ethers
摘要:
A base initiated intermolecular SNAr reaction of pyrazolones with polyfluoroarenes was developed. The process involved the isomerization aromatization of pyrazolone followed by the C-O bond formation via the selective C-F bond cleavage. With this strategy, a wide range of O-pyrazole polyfluoroarylated ethers bearing diverse functional groups were synthesized in mild to good yields. Additionally, our method was also applied to the isoxazol substrates. (C) 2014 Elsevier Ltd. All rights reserved.
One-Pot Asymmetric Synthesis of Spiropyrazolone-Linked Cyclopropanes and Benzofurans through a General Michael Addition/Chlorination/Nucleophilic Substitution Sequence
A sequential and general strategy has been successfully developed for the synthesis of spiropyrazolone scaffolds. This intriguing transformation of the asymmetric multicomponent catalysis process was realized with the combination of Michael addition/chlorination/nucleophilic substitution in a one-pot sequence, giving rise to a series of spiropyrazolones with fully substituted cyclopropanes and spi
Asymmetric Organocatalytic [4 + 1] Annulations Involving a Polarity Reversal Process: A Tandem Catalytic Approach to Highly Functionalized Spiropyrazolone Derivatives
A tandemcatalytic strategy for the asymmetric synthesis of spirocyclopentanone pyrazolones bearing threecontiguousstereocenters and two quaternary carbons with good stereoselectivities has been developed. This strategy, using pyrazolones as efficient C1 synthons and involving a polarity reversal process, not only overcame the energy barrier of the dearomatization process but also avoided nucleophilic