Catalytic asymmetric 1,2-Addition/Lactonization tandem reactions for the syntheses of chiral 3-Substituted phthalides using organozinc reagents

Stereodivergent Synthesis of 1,4-Dicarbonyl Compounds through Sulfonium Rearrangement: Mechanistic Investigation, Stereocontrolled Access to γ-Lactones and γ-Lactams, and Total Synthesis of Paraconic Acids

Although simple γ-lactones and γ-lactams have received considerable attention from the synthetic community, particularly due to their relevance in biological and medicinal contexts, stereoselective synthetic approaches to more densely substituted derivatives remain scarce. The in-depth study presented herein, showcasing a straightforward method for the stereocontrolled synthesis of γ-lactones and γ-lactams, builds on and considerably expands the stereodivergent synthesis of 1,4-dicarbonyl compounds by a ynamide/vinyl sulfoxide coupling. A full mechanistic and computational study of the rearrangement was conducted, uncovering the role of all of the reaction components and providing a rationale for stereoselection. The broad applicability of the developed tools to streamlining synthesis is demonstrated by concise enantioselective total syntheses of (+)-nephrosteranic acid, (+)-rocellaric acid, and (+)-nephromopsinic acid.

Synthesis and Antioxidant/Anti-Inflammatory Activity of 3-Arylphthalides

Phthalides are a group of compounds with relevant biological activities in different areas such as cytotoxicity, anti-stroke activity, neuroprotection, and inflammation, among others. In this study we designed and synthesized a series of 3-arylphthalide derivatives in order to identify their antioxidant and anti-inflammatory activities. The synthetic methodology was established in terms of atom and step economy through a dehydrative coupling reaction between 3-hydroxyphthalide and different properly functionalized arene rings. The evaluation of the antioxidant activity was performed by the ABTS assay and for the anti-inflammatory activity the inhibition of LPS-induced nitric oxide (NO) production in microglial cells Bv.2 and macrophage cells RAW 264.7 was measured. The synthesized compound 3-(2,4-dihydroxyphenyl)phthalide (5a) showed better antioxidant activity than the Trolox standard and caused strong inhibition of NO production in LPS-stimulated Bv.2 and RAW 264.7 cells. In addition, compound 5a reduced the expression of the pro-inflammatory cytokines Il1b and Il6 in RAW 264.7 cells. These results, which are the first account of the anti-inflammatory activity of 3-arylphthalides, suggest that compound 5a could be a promising candidate for more advanced anti-inflammatory studies.

Facile Synthesis and Utilization of Bis(o-phosphinophenyl)zinc as Isolable PZnP-pincer Ligands Enabled by Boron-Zinc Double Transmetallation

Bis(o-phosphinophenyl)zinc derivatives were successfully synthesized by the reaction of o-phosphinophenylboronates with dimethylzinc via boron-zinc double transmetallation. The transmetallation was significantly accelerated by the presence of the ortho PR2 substituent to...

The therapeutic potential of novel isobenzofuranones against Naegleria fowleri

The Free-Living Amoeba species, Naegleria fowleri is the causative agent of a lethal encephalitis known as Primary Amoebic Encephalitis (PAM). Moreover, most of the reported cases are often related to swimming and/or diving in aquatic environments. In addition, the current therapeutic options against PAM are not fully effective and hence, there is an urgent need to develop novel therapeutic agents against this disease. Previously isobenzofuranones compounds have been reported to present antiprotozoal and antifungal activity among others. However, to the best of our knowledge, these molecules have not been previously tested against N. fowleri. Therefore, the aim of this study was to evaluate the activity of 14 novel isobenzofuranones against this pathogenic amoeba. The most active and less toxic molecules, were assayed in order to check induction of Programmed Cell Death (PCD) in the treated amoebae. The obtained results showed that these molecules were able to eliminate N. fowleri trophozoites and also induced PCD. Therefore, the tested isobenzofuranones could be potential therapeutic candidates for the treatment of PAM.

Recent advancements in synthetic methodologies of 3-substituted phthalides and their application in the total synthesis of biologically active natural products

We have provided a critical review that focuses on key developments in the area of 3-substituted phthalides and their role in the development of important biologically active natural products. 3-Substituted phthalides are vital molecules owing to their fascinating biological activity. The scope, isolation, and characterization of various naturally occurring racemic and chiral 3-substituted phthalides have been covered. We have put significant emphasis on recently developed research methodologies for the synthesis of racemic and chiral 3-substituted phthalides. These newer approaches are essential for the development of newer and elegant strategies for the synthesis of phthalide-based or similar molecular architecture with broader substrate scope and higher stereoselectivities. Also, we have discussed the application of 3-substituted phthalides as a precursor for the synthesis of natural products and their analogs.

We have provided contextual information on the chemistry of 3-substituted phthalides and their significance in natural product synthesis.