Visible-Light-Induced Sulfonylation Cyclization to Generate Indole-Fused Medium-Sized -Heterocycles in 2-Me-THF.

A novel visible-light-induced sulfonylation cyclization to indole-fused medium-sized -heterocycles was established under room temperature with biomass-derived 2-Me-THF as the solvent. This reaction proceeds in the absence of external photocatalyst, additive, metal salts, and base. Broad substrate scope, good functional group compatibility, and large-scale synthesis and derivatization via iodination, nitration, chlorination, cyanation, and selenylation demonstrate the utility of this protocol.

Discovery of Novel Oxazolo[4,3-]purine Derivatives as Antitumor Agents through PPIA Interaction.

54 novel oxazolo [4,3-]purine derivatives were designed, synthesized, and evaluated for antitumor activity, among which compound exhibited potent activity against several cancer cell lines. Compound inhibited cell metastasis, arrested the cell cycle in the G/G phase, and induced apoptosis in HCT116 cells. Mechanistic studies revealed that increased ROS levels and led to DNA damage, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction in HCT116 cells.

Pd-Catalyzed Decarboxylative Negishi Coupling of Zinc Aryl Carboxylates with Arylthianthrenium Salts.

We report a Pd-catalyzed decarboxylative Negishi coupling reaction for efficient biaryl synthesis from various zinc aryl carboxylates, including polyfluorobenzoates and heteroaryl carboxylates, using DMF as the solvent. This mild reaction exhibits a broad substrate scope and enables late-stage functionalization of bioactive molecules. Mechanistic studies show that DMF-assisted zinc catalyzes decarboxylation of polyfluorinated aryl carboxylates to generate arylzinc reagents in situ, which then undergo Negishi coupling catalyzed by palladium with arylthianthrenium salts to form biaryl compounds.

Photochemical aerobic sulfonylation-cyclization-selenylation to indole-fused medium-sized N-heterocycles in 2-Me-THF.

Indole-fused medium-sized diazepinones are privileged structural motifs found in many high-value pharmaceuticals. To construct these challenging molecular skeletons, previous methods are mainly achieved by [5+2] annulation strategies with the aid of transition metal (Pd, Rh, Ru) catalyzed oxidative C-H coupling. Herein, we report a novel visible-light-induced sulfonylation-cyclization-selenylation reaction for the rapid construction of highly functionalized indole-fused medium-sized diazepinones with biomass feedstock 2-Me-THF as the medium.

Chemoselective Functionalization of Tertiary C-H Bonds of Allylic Ethers: Enantioconvergent Access to sec,tert-Vicinal Diols.

While enantioenriched alcohols are highly significant in medicinal chemistry, total synthesis, and materials science, the stereoselective synthesis of tertiary alcohols with two adjacent stereocenters remains a formidable challenge. In this study, we present a dual catalysis approach utilizing photoredox and nickel catalysts to enable the unprecedented chemoselective functionalization of tertiary allylic C-H bonds in allyl ethers instead of cleaving the C-O bond. The resulting allyl-Ni intermediates can undergo coupling with various aldehydes, facilitating a novel enantioconvergent approach to access extensively functionalized homoallylic sec,tert-vicinal diols frameworks.

Photoinduced Difluoromethylation Cyclization to Generate Medium-Sized Difluoro-benzo[]azepines.

Compared with the energetically favorable 5- or 6-membered fluoro-functionalized heterocycles, the construction of medium-sized fluoro-heterocycles is relatively under-researched because of their inherently unfavorable enthalpic and entropic nature. Based on rational design and DFT calculations, a novel photocatalytic difluoromethyl radical-initiated intramolecular 7--trig cyclization was realized, thus affording a sustainable route for the synthesis of challenging fluoro-functionalized medium-sized -heterocycles. Depending on atomic dipole moment corrected Hirshfeld population (ADCH) charge calculations, the chemoselective 6--trig radical cyclizations were further replenished.

Indium Mediated Reformatsky-Type Allylation of N--Butanesulfinyl Iminoester with 1,3-Butadiene.

This study presents the indium-mediated three-component radical Reformatsky-type allylation of --butanesulfinyl iminoester with 1,3-butadiene. This novel approach offers a rapid synthesis pathway to valuable homoallylic noncanonical amino acids, demonstrated with over 30 examples showing nice regio- and diastereoselectivity. Mechanism studies revealed that allylindium complexes served as key intermediates, formed through a single-electron reduction of allylic radicals by Indium species.

Three-Component Photochemical Cyclization/Dithiocarbamate Formation of -Difluoro Quinolin-2(1)-ones.

Herein, a novel visible-light-induced 6- difluoromethylation cyclization and subsequent carbo-thioesterification reaction is described. This protocol allows efficient access to valuable -difluoro quinolin-2(1)-ones in moderate to excellent yields under mild conditions. Broad amino sources compatibility, including cyclic morpholine, thiazolidine, thiomorpholine, pyrrolidine, 1,4-oxazepane, 2,6-dimethylmorpholine, -butyl piperazine-1-carboxylate and noncyclic diethylamine, -ethylpropan-1-amine, -benzylethanamine, -benzyl-trimethylsilanamine, dibenzylamine, and -(4-methoxybenzyl)ethanamine, demonstrated the practicability of this strategy.

Photo-Induced Difluoromethylation-Cyclization and Domino Amination-Defluorination to 4-(Aminomethyl)-3-fluoro-quinolinones.

Herein, we report a visible light-induced difluoromethylation cyclization and subsequent amination-defluorination reaction. This protocol allows efficient to valuable 3-fluoro-quinolinones in moderate to excellent yields. A sequential difluoromethylation-cyclization-amination-defluorination mechanism was proposed based on a mechanism study.

Discovery, Synthesis, and Activity Evaluation of Novel Five-Membered Sulfur-Containing Heterocyclic Nucleosides as Potential Anticancer Agents In Vitro and In Vivo.

A series of novel five-membered sulfur-containing heterocyclic nucleoside derivatives were designed, synthesized, and evaluated for their anticancer activities in vitro and in vivo. The structure-activity relationship studies revealed that some of them showed obvious antitumor activities in several cancer cell lines. Among them, compound exhibited remarkable antiproliferative activity against HeLa cells and was more potent than cisplatin (IC = 2.

Titanium catalyzed [2σ + 2π] cycloaddition of bicyclo[1.1.0]-butanes with 1,3-dienes for efficient synthesis of stilbene bioisosteres.

Natural stilbenes have shown significant potential in the prevention and treatment of diseases due to their diverse pharmacological activities. Here we present a mild and effective Ti-catalyzed intermolecular radical-relay [2σ + 2π] cycloaddition of bicyclo[1.1.

Radical Crotylation of Aldehydes with 1,3-Butadiene by Photoredox Cobalt and Titanium Dual Catalysis.

Metal-hydride hydrogen atom transfer (MHAT) has been recognized as a powerful method for alkene functionalization; however, photochemical MAT-mediated chemoselective functionalization of dienes remains undeveloped. In this study, we report a radical strategy (1e) through MHAT using photoredox cobalt and titanium dual catalysis for aldehyde crotylation with butadiene, achieving excellent regio- and diastereoselectivity.

Photoinduced copper-catalyzed selective three-component 1,2-amino oxygenation of 1,3-dienes.

This study presents a highly effective method for the photoinduced copper-catalyzed 1,2-amino oxygenation of 1,3-dienes. This synthetic strategy involves the dual roles of a single copper catalyst, which can act as a photosensitizer to generate nitrogen radicals and can also react with allyl radicals single electron transfer (SET) processes. The method produces a range of quaternary carbon-centered allyl carboxylic esters and tertiary ethers with high yields and excellent regioselectivity under mild reaction conditions.

Difunctionalization of 1,3-Butadiene via Sequential Radical Thiol-ene Reaction and Allylation by Dual Photoredox and Titanium Catalysis.

Recently, radical difunctionalization of the feedstock 1,3-butadiene has become an attractive strategy for increasing molecular complexity. Herein, we present a novel approach that effectively combines radical thiol-ene chemistry with Ti catalysis to enable a three-component aldehyde allylation using 1,3-butadiene as an allyl group source under visible light conditions. This sustainable and straightforward method has facilitated the rapid production of diverse allylic 1,3-thioalcohols with exceptional regio- and diastereoselectivity.

One-Pot Synthesis of -Diphenyl-2-benzothiazolamines from 1-(2-Iodophenyl)-3-phenylthioureas and Iodobenzenes.

An efficient copper-catalyzed synthesis of a variety of -diphenyl-2-benzothiazolamines was developed. Starting from substituted 1-(2-iodophenyl)-3-phenylthioureas and substituted iodobenzenes, the reaction proceeded smoothly via a tandem manner in the presence of CuI to afford the corresponding -diphenyl-2-benzothiazolamine derivatives with good functional group tolerance. The protocol features simple performance, easily available starting materials, a one-pot manner, and good functional group tolerance, providing a practical strategy for the preparation of poly-functionalized amines.

Synthesis of Unsymmetric Thiosulfonates Starting from N-Substituted -Thiocarbamates: Easy Access to the S-SO Bond.

Using phenyliodine diacetate as an oxidant and nickel acetate as a promoter, a wide range of unsymmetric thiosulfonates could be furnished easily in moderate to excellent yields starting from N-substituted -thiocarbamates and sodium sulfinates. This protocol features mild conditions, short reaction times, and high atomic utilization, which can provide an alternative method for the synthesis of unsymmetric thiosulfonates. In addition, the reaction could be scaled up on a gram scale, showing potential application value in industry.

Easy S-Alkylation of Arylthioureas and 2-Mercaptobenzothiazoles Using Tetraalkylammonium Salts under Transition-Metal-Free Conditions.

A highly-efficient and practical method for S-alkylation of arylthioureas was reported. Using tetraalkylammonium salts as alkylation reagents, a series of 68 S-substituted aryl-isothioureas were obtained in good to excellent yields under transition-metal-free conditions. The protocol features simple performance, broad functional group tolerance, good to excellent yields, and easily available starting materials, showing potential synthetic value for the preparation of diverse biologically or pharmaceutically active compounds.

Synthesis of Homoallylic Amines by Radical Allylation of Imines with Butadiene under Photoredox Catalysis.

Ionic (2 e ) nucleophilic addition of allylmetal regents to imines dominates the synthesis of homo-allyl amine; however, single electron (1 e ) mediated imine allylation with feedstocks butadiene as an alternative allyl source remains unexplored. In this work, we report a conceptually different radical-radical cross-coupling strategy for the synthesis of a homoallyl amine between an α-amino alkyl radical and a transient allylic radical. This metal-free method provided a novel approach for the synthesis of homoallylic amines (>80 examples) from readily available materials with excellent regioselectivity and exceptional broad functional group compatibility.

Photochemical Nozaki-Hiyama-Kishi Coupling Enabled by Excited Hantzsch Ester.

This work reports the first photochemical Nozaki-Hiyama-Kishi coupling enabled by bioinspired Hantzsch ester. The salient feature of this process is that commercially available and low-cost organic photoactive Hantzsch ester can serve as both an electron and a proton donor to reduce Cr/Ni to low-valent species and hydrolyze the Cr-alkoxy bond, thus bypassing the use of stoichiometric metallic reductants and additives such as TMSCl and CpZrCl. The mild conditions and operationally easy method showed broad compatibility with various alkenyl triflates and aldehydes, including electron-poor pentafluorobenzaldehyde which failed under previous conditions.

One-Pot Synthesis of 1,2-Disubstituted Indoles from 2-Ethynylanilines and Benzaldehydes.

An efficient synthesis of a variety of 1,2-disubstituted indoles from 2-ethynylanilines was developed. Using 2-ethynylanilines and benzaldehydes as starting materials, the target products (1,2-disubstituted indoles) were obtained smoothly through condensation, reduction, and subsequent cyclization. Various functional groups attached to the aryl ring of 1,2-disubstituted indoles were well tolerated.

One-Pot Synthesis of Benzoazole-Substituted Thioenamines via a Cross Dehydrogenation Coupling (CDC) Reaction.

An iodine-catalyzed synthesis of benzoazole-substituted thioenamines in a one-pot manner was reported. Using 2-aminothiophenols (or 2-aminophenols or 1,2-phenylenediamines), tetramethylthiuram disulfide (TMTD), and enamines (mainly indoles) as starting materials, the target C(sp)-S formation products (benzoazole-substituted thioenamines) could be furnished smoothly in good yields. The reaction might proceed through an electrophilic substitution pathway in a cross dehydrogenation coupling (CDC) manner.

Activation of Chromium Catalysts by Photoexcited Hantzsch Ester for Decarboxylative Allylation of Aldehydes with Butadiene.

Metallaphotocatalysis often needs light-absorbing metal-polypyridyl complexes, semiconductors, or organic dyes, which can modify the oxidation state of metal catalysts. Here, we first report that photoexcitation of Hantzsch ester can directly activate chromium reagents through a single-electron transfer process. The synthetic application was demonstrated through a photoredox decarboxylative allylation of aldehydes with feedstock butadiene without exogenous photocatalysts, metallic reductants, or additives.

CsCO-Promoted Hydrothiolation of Alkynes with Aryl Thioureas: Stereoselective Synthesis of ()-Vinyl Sulfides.

A metal-free CsCO-promoted hydrothiolation of alkynes with aryl thioureas for stereoselective synthesis of ()-vinyl sulfides has been reported. Vinyl thioethers were obtained without a metal catalyst in good yields anti-Markovnikov and addition. The protocol features a broad substrate scope of the starting materials, high atom economy, good yields, and exclusive stereoselectivity, showing potential synthetic value for the synthesis of a diversity of ()-vinyl thioethers.

Design, Synthesis, and Activity Evaluation of Novel Acyclic Nucleosides as Potential Anticancer Agents and .

In the present work, 103 novel acyclic nucleosides were designed, synthesized, and evaluated for their anticancer activities and . The structure-activity relationship (SAR) studies revealed that most target compounds inhibited the growth of colon cancer cells , of which 3-(6-chloro-9-purin-9-yl)dodecan-1-ol () exhibited the most potent effect against the HCT-116 and SW480 cells with IC values of 0.89 and 1.

Controlled synthesis of high quality scandium-based nanocrystals as promising recyclable catalysts for silylcyanation reaction.

High quality (monodisperse and well-defined) scandium based ternary fluoride nanocrystals of NaScF and KScF were successfully fabricated via a one-pot colloidal synthesis method. These nanocrystals can play the part of hard Lewis acid catalysts by providing Lewis acid sites on account of the unique electronic structure, i.e.