Catalytic Enantioselective Aza-Friedel-Crafts Reaction of Ketimines and Indoles for Constructing Tetrasubstituted Carbon Centers Adjacent to Two Heteroatoms.

A highly enantioselective aza-Friedel-Crafts reaction of benzothiophene-2,3-dione-derived ketimines and indoles catalyzed by BINOL-derived chiral phosphoric acid was developed for the first time. This protocol enabled the synthesis of structurally diverse enantiopure hybrid 3-indolylmethanamine-benzothiophenes featuring a chiral quaternary carbon center adjacent to both N and S atoms, achieving high yields and high to excellent enantioselectivities (up to 99% yield and 99% ee). The reaction exhibits broad substrate scope, high reactivity, simple operation, and mild conditions.

CPA-Catalyzed Enantioselective Para-Addition of Anilines to Cyclic Thioimidates: A Route to Chiral ,-Acetal-Containing Quaternary Carbon Stereogenic Centers.

Enantiopure ,-acetals represent a vital class of sulfur-containing compounds commonly found in natural products and pharmaceutical agents. We herein report the first chiral phosphoric acid-catalyzed, highly -chemo, site-, and enantioselective para-addition of anilines to cyclic thioimidates. This protocol provides a new approach for the preparation of chiral ,-acetal-containing quaternary carbon stereogenic centers, achieving high yields with excellent enantioselectivities (up to 96% yield and 99% ee).

Enantioselective Synthesis of Highly Functionalized 2,3-Dihydrobenzofuran Derivatives via Steric Hindrance-Overcoming Strategy.

The asymmetric cycloaddition reaction of -quinone monoimides is a significant research focus for constructing benzofused heterocycles. However, due to steric effects, achieving efficient cycloaddition at highly sterically hindered site is challenging but practically valuable. Herein, we develop an asymmetric [3 + 2] cycloaddition reaction of -quinone monoimides with 1-vinylnaphthalen-2-ols and 3-vinylindoles via steric hindrance-overcoming strategy.

Catalytic Enantioselective Access to Planar-Chiral Macrocyclophanes.

Macrocyclophanes are a class of macrocyclic molecules featuring aliphatic ansa chains linking non-adjacent positions of an aromatic ring, which have garnered significant attention due to their extensive applications in biological activity, pharmaceutical research, and selective optical recognition. In this review, it summarizes recent advancements in the catalytic enantioselective synthesis of planar-chiral macrocyclophanes, focusing on various synthetic routes, including: a) transition-metal-catalyzed enantioselective alkyne cyclotrimerization for planar construction; b) (dynamic) kinetic resolution of achiral or prochiral macrocyclophanes; c) enantioselective substitution of aromatic rings; and d) enantioselective macrocyclization for the formation of ansa chains. The aim is to highlight the state-of-the-art advances in catalytic enantioselective construction of planar-chiral macrocyclophanes and to push this field toward new horizons.

Enantioselective Friedel-Crafts Reaction for the Synthesis of 4,7-Difunctionalized Indoles Featuring a Chiral Heteroatom-Substituted Quaternary Carbon at the C7 Position.

Enantioselective functionalization of 4-aminoindoles at the site-specific C7 position via a chiral phosphoric acid-catalyzed Friedel-Crafts reaction with cyclic thioimidates was developed. This approach enables the formation of 4,7-difunctionalized indoles incorporating the chiral ,-acetal motif with excellent yield and enantioselectivity (up to 99% yield and >99% ee). The protocol is also compatible with isatin-derived ketoimines for the highly enantioselective synthesis of 4,7-difunctionalized indole derivatives bearing aza-quaternary carbon at the C7 position.

Asymmetric aza-Friedel-Crafts reaction of newly developed ketimines: access to chiral indeno[1,2-]quinoxaline architectures.

The functionalized 11-amino-indeno[1,2-]quinoxaline scaffold is a pivotal structural motif in diverse bioactive compounds. In this study, we developed a chiral phosphoric acid catalysed enantioselective aza-Friedel-Crafts reaction between indeno[1,2-]quinoxalin-11-imines and indoles. This methodology enables the synthesis of chiral hybrid architectures incorporating both 11-aminoindeno[1,2-]quinoxaline and indole moieties, achieving exceptional synthetic efficiency (up to 99% yield) with outstanding stereocontrol (up to 99% ee).

Simultaneously Tailoring Hydrostability and Photoelectroactivity in Heterocluster Metal-Organic Frameworks for Efficient Photocatalytic Hydrogen Production.

The simultaneous enhancement of structural stability and photoelectroactivity in metal-organic frameworks (MOFs) remains a critical challenge for sustainable photocatalytic hydrogen (H) production. Herein, an atomically-precise heterocluster assembly approach is presented to construct two isostructural 3D MOFs, CuSL-CuX (X = Cl, Br), featuring a cds net. CuSL-CuXs integrate hexanuclear copper-sulfur {CuS} cluster and dinuclear copper-halogen {CuX} cluster, which not only impart exceptional stability across a broad pH range (1-14) but also enable wide visible-light absorption, tailored redox potentials, and efficient charge-carrier dynamics.

Palladium-catalyzed decarboxylation of vinyloxazolidine-2,4-diones used in the divergent reaction with 2-alkynylphenols and 2-alkynylanilines.

The generated aza-π-allylpalladium species, formed the palladium-catalyzed decarboxylation of vinyloxazolidine-2,4-diones, were successfully used for the divergent reaction with 2-alkynylphenols and 2-alkynylanilines. Using Pd(dba)·CHCl as the catalyst and Cu(OTf) as the additive, a range of 2,3-disubstituted benzofurans and indoles were obtained in moderate to excellent yields. However, when PPh ligand was added, a series of γ-/-substituted α,β-unsaturated amides were obtained in acceptable yields.

Palladium-Catalyzed Decarboxylative Allylic Sulfonylation of Vinyloxazolidine-2,4-diones: Synthesis of γ-Sulfonyl-α,β-unsaturated Amides.

A palladium-catalyzed decarboxylative allylic sulfonylation reaction of vinyloxazolidine-2,4-diones with inexpensive and readily available sodium sulfinates as sulfonylation reagents has been developed. Under the catalysis of Pd(PPh), a wide range of γ-sulfonyl-α,β-unsaturated amides can be synthesized in good to excellent yields. The developed protocol is characterized by exclusive regioselectivity, mild reaction conditions, broad substrate scope, good functional group tolerance, and suitable for gram-scale synthesis.

The Progress of Reductive Coupling Reaction by Iron Catalysis.

The transition metal catalyzed coupling reaction has revolutionized the strategies for forging the carbon-carbon bonds. In contrast to traditional cross-coupling methods using pre-prepared nucleophilic organometallic reagents, reductive coupling reactions for the C-C bonds formation provide some advantages. Because both coupling partners are reduced in the final products using a stoichiometric amount of a reductant, this approach not only avoids the need to use sensitive organometallic species, but also provides an orthogonal and complementary access to classical coupling reaction.

Synthesis of 6/5/3-Fused Tricyclic Scaffolds via Multistep Cascade Cyclization of α-Aryl Vinylsulfoniums with -Quinamines and -Quinols.

Herein, we present a straightforward approach to access hydroindoline-5-one-based 6/5/3-fused polycyclic ring structures through multistep cascade reactions involving α-aryl vinylsulfoniums and -quinamines. The reactions proceed smoothly under mild conditions to deliver the desired products in generally good isolated yields. This protocol is also applicable to the cascade cycloaddition reactions of α-aryl vinylsulfoniums and -quinols, effectively generating complex tricyclic scaffolds.

Corrigendum: Ultrasound-based radiomics analysis for differentiating benign and malignant breast lesions: from static images to CEUS video analysis.

[This corrects the article DOI: 10.3389/fonc.2022.

Palladium-Catalyzed Cycloaddition Reactions of π-Allylpalladium 1,4-Dipoles with 1,3,5-Triazinanes: Access to Hexahydropyrimidines, 1,3-Oxazinanes, and 1,5-Diazocanes.

Palladium-catalyzed decarboxylation of 5-methylene-1,3-oxazinan-2-ones and 5-methylene-1,3-dioxan-2-ones to generate aza-π-allylpalladium and oxa-π-allylpalladium 1,4-dipoles for [4 + 2] cycloaddition reaction with 1,3,5-triazinanes was developed, affording a wide range of hexahydropyrimidine and 1,3-oxazinane derivatives in good to excellent yields (up to 99%). The acyclic sulfonamido-substituted allylic carbonates as aza-π-allylpalladium 1,4-dipole precursors also apply to the developed synthesized strategy, achieving the synthesis of hexahydropyrimidines. Moreover, the in situ-generated aza-π-allylpalladium 1,4-dipoles undergoing dimeric [4 + 4] cycloaddition were also demonstrated by the construction of 1,5-diazocane derivatives.

Palladium-Catalyzed Asymmetric Decarboxylation of 5-Vinyloxazolidine-2,4-Diones Triggering the Dearomatization of Electron-Deficient Indoles for the Synthesis of Chiral Highly Functionalized Pyrroloindolines.

A catalyst system consisting of a chiral phosphoramidite ligand and Pd(dba)·CHCl causes the decarboxylation of 5-vinyloxazolidine-2,4-diones to generate amide-containing aza-π-allylpalladium 1,3-dipole intermediates, which are capable of triggering the dearomatization of 3-nitroindoles for diastereo- and enantioselective [3+2] cycloaddition, leading to the formation of a series of highly functionalized pyrroloindolines containing three contiguous stereogenic centers with excellent results (up to 99% yield, 88:12 dr, and 96% ee).

Thiol-Triggered Tandem Dearomative Michael Addition/Intramolecular Henry Reaction of 2-Nitrobenzofurans: Access to Sulfur-Containing Polyheterocyclic Compounds.

An efficient dearomative cyclization of 2-nitrobenzofurans via a thiol-triggered tandem Michael addition/intramolecular Henry reaction has been developed. A range of thiochromeno[3,2-]benzofuran-11-ols and tetrahydrothieno[3,2-]benzofuran-3-ols could be obtained in up to 99% yield and up to >20:1 dr. The valuable thiochromone fused benzofurans could be prepared with the reaction of 2-nitrobenzofurans and 2-mercaptobenzaldehyde via the tandem dearomative Michael addition/intramolecular Henry reaction/rearomatization/oxidative dehydrogenation process in a one-pot two-step operation.

Synthesis of Benzofuro[3,2-]indol-3-one Derivatives via Dearomative (3 + 2) Cycloaddition of 2-Nitrobenzofurans and -Quinamines.

An efficient dearomative (3 + 2) cycloaddition of -quinamines and 2-nitrobenzofurans has been developed. This reaction proceeds smoothly under mild conditions and affords a series of benzofuro[3,2-]indol-3-one derivatives in good to excellent yields (up to 98%) with perfect diastereoselectivities (all cases > 20:1 ). The scale-up synthesis and versatile derivatizations demonstrate the potential synthetic application of the protocol.

hOGG1: A novel mediator in nitrosamine-induced esophageal tumorigenesis.

Background: The effect of human 8-Oxoguanine DNA Glycosylase (hOGG1) on exogenous chemicals in esophageal squamous cell carcinoma (ESCC) remain unclear. The study plans to determine hOGG1 expression levels in ESCC and possible interactions with known environmental risk factors in ESCC.

Material And Methods: We analyzed levels of exposure to urinary nitrosamines in volunteers from high and low prevalence areas by GC-MS.

Palladium-Catalyzed Ligand-Directed Divergent Decarboxylative Cycloadditions of Vinyloxazolidine-2,4-diones with 1,3,5-Triazinanes.

This study demonstrates a highly efficient regiodivergent ligand-controlled palladium-catalyzed cycloaddition reaction of vinyloxazolidine-2,4-diones with 1,3,5-triazinanes. In the presence of a diphosphine ligand, the reaction proceeds via a (5+2) cycloaddition pathway to afford 1,3-diazepin-4-ones in excellent yields, while using a monophosphine ligand, the reaction proceeds smoothly via a (3+2) cycloaddition pathway to give imidazolidin-4-ones in good yields.

Cu-Catalyzed Direct Asymmetric Mannich Reaction of 2-Alkylazaarenes and Isatin-Derived Ketimines.

The first direct catalytic asymmetric Mannich reaction of 2-alkylazaarenes and ketimines was realized with a chiral Cu-bis(oxazoline) complex as the catalyst. The asymmetric addition of 2-alkylpyridines to isatin-derived ketimines proceeded smoothly to afford α,β-functionalized 2-substituted pyridines bearing 3-amino-3,3-disubstituted oxindole motifs with excellent results (≤99% yield, 99:1 dr, and 98% ee). The catalytic system was also extended to 2-alkylbenzothiazoles as nucleophiles for the asymmetric Mannich reaction of ketimines.

A New Reaction Mode of 3-Halooxindoles: Acting as C-C-O Three-Atom Components for (3+3) Cycloaddition to Access Indolenine-Fused 2-1,4-Oxathiines.

Herein, we report an unprecedented implementation of 3-halooxindoles as C-C-O three-atom components for (3+3) cycloaddition with pyridinium 1,4-zwitterionic thiolates, affording structurally diverse indolenine-fused 2-1,4-oxathiines in moderate to high yields. A combined experimental and computational mechanistic study suggests that the reaction proceeds through addition of a S conjugate to the -azaxylylene intermediate, followed by O-Michael addition and a sequential retro-Michael addition/pyridine extrusion pathway.

Multilevel-Regulated Metal-Organic Framework Platform Integrating Pore Space Partition and Open-Metal Sites for Enhanced CO Photoreduction to CO with Nearly 100% Selectivity.

Rational design and regulation of atomically precise photocatalysts are essential for constructing efficient photocatalytic systems tunable at both the atomic and molecular levels. Herein, we propose a platform-based strategy capable of integrating both pore space partition (PSP) and open-metal sites (OMSs) as foundational features for constructing high-performance photocatalysts. We demonstrate the first structural prototype obtained from this strategy: pore-partitioned NiTCPE- (TCPE = 1,1,2,2-tetra(4-carboxylphenyl)ethylene, = partitioned topology).