Construction of quaternary alkyl motifs through palladium-catalyzed oxidative coupling of 1,3-dicarbonyl compounds with alkenes followed by C-C bond cleavage

A palladium-catalyzed coupling reaction has been developed for the generation of tertiary alkylation products by reacting olefins with diversely functionalized 1,3-dicarbonyls. The reaction involves the tertiary C-H alkylation of 1,3-dicarbonyls with olefins to produce a tertiary alcohol, followed by C-C bond cleavage.

Synthesis of 3-substituted 2-oxindoles from secondary α-bromo-propionanilides via palladium-catalyzed intramolecular cyclization

In contrast to aromatic halides, coupling reactions involving oxidative addition of alkyl halides, especially secondary or tertiary halides, to transition metals tend to be more challenging. Herein a palladium-catalyzed intramolecular cyclization of α-bromo-propionanilides has been developed, delivering a series of 3-substituted 2-oxindoles in high yields. The method features easy to prepare starting materials, broad substrate scope and excellent functional group tolerance. A detailed mechanistic investigation has been performed.

Leishmanicidal and cytotoxic activities and 4D-QSAR of 2-arylidene indan-1,3-diones

The indan-1,3-dione and its derivatives are important building blocks in organic synthesis and present important biological activities. Herein, the leishmanicidal and cytotoxicity evaluation of 16 2-arylidene indan-1,3-diones is described. The compounds were evaluated against the leukemia cell lines HL60 and Nalm6, and the most effective ones were 2-(4-nitrobenzylidene)-1H-indene-1,3(2H)-dione (4) and 4-[(1,3-dioxo-1H-inden-2(3H)-ylidene)methyl]benzonitrile (10), presenting IC₅₀ values of around 30 µmol/L against Nalm6. The leishmanicidal activity was assessed on Leishmania amazonensis, with derivative 4 (IC₅₀ = 16.6 µmol/L) being the most active. A four-dimensional quantitative structure-activity analysis (4D-QSAR) was applied to the indandione derivatives, through partial least-squares regression. The statistics presented by the regression models built with the selected field descriptors of Coulomb (C) and Lennard-Jones (L) nature, considering the activities against L. amazonensis, HL60, and Nalm6 leukemia cells, were, respectively, R² = 0.88, 0.92, and 0.98; Q² = 0.83, 0.88, and 0.97. The presence of positive Coulomb descriptors near the carbonyl groups indicates that these polar groups are related to the activities. Besides, the presence of positive Lennard-Jones descriptors close to substituents R³ or R¹ indicates that bulky nonpolar substituents in these positions tend to increase the activities. This study provides useful insights into the mode of action of indandione derivatives for each biological activity involved.

Highly modular dipeptide-like organocatalysts for direct asymmetric aldol reactions in brine

The dipeptide-like organocatalysts have been developed for asymmetric aldol reactions in brine to achieve high yields and enantioselectivities with 1 mol% catalyst-loading.