One-pot tandem reduction and site-selective halogenation of nitroarenes.

Halogenated aryl amines are a widely used chemical feedstock in the pharmaceutical and agrochemical industries. Achieving a single regioselective product from the -selective halogenation of the aryl ring is significantly challenging because of the presence of several C-H bonds with similar reactivities. In this study, single -halogenated aniline derivatives were prepared by the cascade -selective halogenation (Cl, Br) and reduction of nitrobenzene derivatives using a mixture of SnCl/SnCl salts.

A Regioselective [3 + 2] Cycloaddition of Alkynols and Ketones To Access Diverse 1,3-Dioxolane Scaffolds.

This study presents a stepwise exoselective [3 + 2] cycloaddition reaction of alkynols with ketones, leading to the synthesis of 4-methylene-1,3-dioxolane derivatives. Remarkably, without any Thorpe-Ingold induced effect, the cyclization reaction was demonstrated with complete regio- and chemoselectivity, which was solely promoted by cesium carbonate. A wide range of unactivated ketones are viable under these mild reaction conditions, and both primary and tertiary alkynols are compatible with these cyclization reactions.

Design and synthesis of sirtinol analogs as human neutrophil elastase inhibitors.

Human neutrophil elastase (HNE) overexpression has a crucial role in most acute inflammation and alpha1-antitrypsin deficiency syndromes observed in humans, triggering neutrophil invasion and activation of macrophage inflammatory and proteolytic effects, leading to tissue damage. Manipulating HNE level homeostasis could potentially help treat neutrophilic inflammation. Previous studies have shown that sirtinol (1) has a specific influence on HNE and potently attenuates acute lung injury and hepatic injury mediated by lipopolysaccharide or trauma hemorrhage.

Acid-Promoted Intramolecular Decarbonylative Coupling Reactions of Unstrained Ketones: A Modular Approach to Synthesis of Acridines and Diaryl Ketones.

Herein, we reported Lewis acid- or Brønsted acid-promoted intramolecular C(sp)-C(sp) bond cleavage and a novel C(sp)-C(sp) bond-forming cascade reaction to synthesize the acridine motif. The metal-free oxidation of the alkyne motif generated the in situ ketone group extracted via a decarbonylation reaction. The mechanistic studies revealed that the electrophilic -iodo species triggered key decarbonylation reactions via consecutive dearomatization/aromatization reactions.

Regio- and chemoselective synthesis of nitrogen-containing heterocycles via the oxidative cascade cyclization of unactivated 1,n-enynes.

The development of a method for performing radical initiated intramolecular cascade cyclization of 1,n-enynes provided a competent protocol for producing structurally diverse complex heterocycles. Herein, we demonstrate I2/TBHP promoted, solvent controlled, regio- and chemoselective 5-exo-trig or 6-endo-trig radical cyclization of electronically unbiased 1,n-enynes to synthesize nitrogen-containing heterocycles. These metal-free protocols confer access to synthetically robust piperidine motif-bearing iodinated-homoallylic alcohol and pyrrolidine fused cyclopropane rings.

FeCl-Promoted ring size-dictating diversity-oriented synthesis (DOS) of N-heterocycles using in situ-generated cyclic imines and enamines.

The FeCl-promoted ring size-controlled oxidative activation of o-alkynylanilines opens up a complementary appealing protocol for poly-N-heterocycle synthesis. When electron-poor π-alkyne iron species combine with cyclic enamines obtained from cyclohexanone and β-tetralone, they undergo a regioselective 6-exo-dig cyclization to afford the corresponding dibenzo[b,j][1,10]phenanthrolines and 12-benzoylated dihydrobenzo[a]acridine skeletons. Later, these acridine motifs become completely unsaturated due to dehydrogenative aromatization via the aza-allyl oxidation intermediate.

Palladium-Catalyzed Double-Isocyanide Insertion via Oxidative N-O Cleavage of Acetyl Oximes: Syntheses of 2H-Pyrrol-2-imines.

The palladium-catalyzed reaction of acetyl oximes with isocyanides was developed for the synthesis of 2H-pyrrol-2-imines. The key steps were (i) generation of an enamido-palladium(II) species, (ii) migratory double-isocyanide insertion, and (iii) cyclization. The scope of the synthesis of some 2H-pyrrol-2-imines was extended to the synthesis 1H-pyrrole-2,3-dione/1H-benzo[g]indole-2,3-dione derivatives via acid hydrolysis in a sequential one-pot manner.