A Rh-catalyzed three-component reaction for the diastereoselective synthesis of pyrazolone derivatives with contiguous quaternary stereocenters

Diastereoselective aldol-type interception of phenolic oxonium ylides for the direct assembly of 2,2-disubstituted dihydrobenzofurans

A Rh₂(OAc)₄ catalyzed intermolecular aldol-type interception of phenolic oxonium ylides with isatins has been developed, which provides an effective access to 2,2-disubstituted dihydrobenzofuran derivatives containing 3-hydroxyoxindole in high yields and with high diastereoselectivities under mild reaction conditions. The antiproliferation activity of these synthesized dihydrobenzofuran and 3-hydroxyoxindole hybrid products has been tested via the CCK8 assay in different cancer cell lines; compounds 3s and 3t exhibit good anticancer potency against human colon cancer cells (HCT116 cells, 3s: IC₅₀ = 15.99 μM; 3t: IC₅₀ = 14.48 μM) compared to other tested compounds.

Multicomponent Reactions Involving Diazo Reagents: A 5-Year Update

This review summarizes recent developments in multicomponent reactions of diazo compounds. The role of diazo reagent and the type of interaction between components was analyzed to structure the discussion. In contrast to previous reviews on related topics mostly focused on metal catalyzed transformations, a substantial amount of organocatalytic or catalyst-free methodologies is covered in this work.

TFA-mediated synthesis of functionalized pyrano[2,3-c]pyrazoles from pyrazol-3-ones, active carbonyl compounds and tert-BuOH

Functionalized pyrano[2,3-c]pyrazoles were synthesized from 2,4-dihydro-3H-pyrazol-3-ones, active carbonyl compounds and tert-BuOH in the presence of trifluoroacetic acid at 65 °C. These reactions are proceeded by acid catalyzed generation of isobutylene from tert-BuOH for LUMO_diene-controlled inverse [4 + 2] cycloaddition reaction with in situ-generated vinylidenepyrazolones.

Palladium-catalysed oxidative nucleophilic allylation between alkenes and activated ketimines

A direct linear regioselective oxidative allylation reaction between alkenes and activated ketimines has been developed by using a Pd(OAc)2/2,6-dimethyl-1,4-benzoquinone system.