As an important structural unit containing nitrogen-oxygen heterocycles,benzoxazine widely exists in drug mole-cules and functional materials.Especially in the field of drug research and development,it exhibits diverse biological activities such as anti-inflammatory and antifungal properties,becoming a highly potential active molecular skeleton.Unsaturated aro-matic hydrocarbon derivatives(such as N-acyl-2-alkenylanilines),due to the synergistic reactivity between unsaturated their unsaturated bonds and heteroatomic sites,are excellent raw materials for constructing benzoxazine skeletons via radical cas-cade reactions,showing broad academic research value and industrial application prospects.Focusing on three core directions:photo-mediated radical cascade reactions,electrochemical radical cascade reactions,and transition metal-mediated radical cascade reactions,the progress in the synthesis of such compounds via radical cascade reactions over the past 10 years is sys-tematically reviewed.Special attention is paid to such scientific issues as the reaction mechanisms and substrate scopes of different synthetic strategies.Finally,the existing challenges in current research are summarized,and the development direc-tions of the synthetic strategies are prospected.

Direct hydroalkylation of ynazoles, facilitating the efficient synthesis of linear N‐β‐vinylazoles, is accomplished through the functionalization of sp3 C‐H bonds using trace amounts of dioxygen as an initiator. This reagent‐free method eliminates the need for exogenous reagents and proceeds through a radical chain mechanism involving dual hydrogen atom transfer (HAT) processes. Its application potential is exemplified through the implementation of scale‐up operations.

The development of sustainable and efficient synthetic methodologies for high-valued chemicals from renewable resources is one of the principal aims of chemical industries. Herein, we document the combination of photocatalytic PCET and SCS-enabled direct C-H benzylation of N-heteroarenes with benzaldehydes as the benzyl sources. A variety of benzylated N-heteroarenes was obtained in moderate to excellent yields at room temperature under metal-, oxidant-free and mild conditions in continuous-flow mode. Mechanistic studies indicated that this benzylation proceeded via PCET activation of benzaldehydes to yield ketyl radicals, the addition of the ketyl radicals to N-heteroarenes to form C-C(OH) bonds, the SCS cleavage to produce benzylic radical and HAT process to deliver the benzylated products.

The presence of a high density of defects at the perovskite/electron transport layer (ETL) interface results in significant nonradiative recombination losses, thus impeding the efficiency enhancement of perovskite/silicon tandem solar cells (TSCs). In this investigation, a metallocene-based molecule, cobalt (III) dichlorophene hexafluorophosphate (CcPF6), is employed for perovskite surface passivation. To maximize its efficacy, the molecule is dissolved in a mixed solvent of acetonitrile and chlorobenzene, leading to the reconstruction of the perovskite surface and effective passivation of surface defects. This modification strategy substantially enhances the overall efficiency of perovskite/silicon tandem solar cells by mitigating the issue of low fill factor resulting from non-uniform coating of the top perovskite layer on the textured silicon bottom cell. Leveraging a double-sided textured silicon heterojunction (HJT) bottom cell, a certified power conversion efficiency (PCE) of 30.43% for a monolithic perovskite/silicon TSC (1.00 cm2) is achieved, featuring an open-circuit voltage (Voc) of 1.93 V and a fill factor (FF) of 78.43%. After storage in the drying cabinet (5% humidity at 20 degrees C) for 1000 h, the device retains 94.27% of its initial performance. An approach is proposed to modify perovskite surface utilizing mixed solvents and metallocene materials. The mixed solvent efficiently exposes trap defects on the perovskite surface, while the high electronegativity metallocene material effectively passivates these defects, significantly enhancing carrier transport efficiency. A certified PCE exceeding 30% is obtain on perovskite/silicon tandem solar cells. image

Herein, we report a cascade process that is initiated by radical Brook rearrangement and promoted by 1,5-hydrogen atom transfer. A series of alpha-fluoroalkyl alkyl secondary alcohols were synthesized with unactivated terminal olefins and alpha-fluoroalkyl-alpha-silyl methanols. The strategy features mild reaction conditions and broad substrate scope. The diversified down-stream transformations demonstrated the synthetic potential of the reaction.

Incorporation of fluorine has always been a conventional strategy for designing new drugs and materials because it can usually improve the physiochemical and physiological properties of organic molecules. Among various organofluorine compounds, alpha-fluoroalkyl alcohols are of particular importance and they are important skeletons of bioactive molecules. Herein, we report a three components olefin difunctionalization reaction for the synthesis of a-alpha fluoroalkyl alcohols through manganese-catalyzed radical Brook rearrangement of alpha-fluoroalkyl-alpha-silyl methanols. The operationally simple reaction showed broad substrate scope, and the product could be prepared on gram scale. Twenty-five alpha-fluoroalkyl alcohols have been synthesized in 44%similar to 86% yields. It is compatible with a variety of halogen substituents (F, Cl, Br), electron donating OMe and naphthalenyl groups and is also suitable for different symmetrical aryl olefins, asymmetric aryl olefins and alkoxyl olefins. The reaction is also compatible with different nucleophiles such as aryl carboxylic acids and anilines. Besides, the reaction is compatible with a a-alkyl alcohol which afford the desired olefin difunctionalization product in 36% yield. A representative procedure is described as follows. In the glovebox, alpha-difluoromethyl-alpha-dimethylphenylsilyl methanol (64.8 mg, 0.3 mmol), 1,1-stilbene (223 mg, 0.3 mmol), benzoic acid (110 mg, 0.9 mmol), Mn(OAc)(2) (2.6 mg, 0.015 mmol), tert-butyl peroxybenzoate (TBPB, 175 mg, 0.9 mmol), 4 angstrom MS (30 mg) and dry dichloromethane (DCM, 0.5 mL) were added to a dry 10 mL reaction tube equipped with a magnetic agitator. The reaction mixture was then removed from the glove box, stirred at 70 degrees C for 1 h. Then tetrabutylammonium fluoride (TBAF, 0.36 mmol) was added at 0 degrees C. After 30 min, the reaction mixture was quenched with saturated sodium bicarbonate aqueous solution (10 mL), extracted with ethyl acetate (10 mLx3). The organic phase was combined, washed with saturated NaCl aqueous solution and dried with anhydrous sodium sulfate and concentrated under vacuum. Then the crude product was purified by silica gel column chromatography to obtain corresponding target product.

Single-atom catalysts (SACs) have emerged as crucial players in catalysis research, prompting extensive investigation and application. The precise control of metal atom nucleation and growth has garnered significant attention. In this study, we present a straightforward approach for preparing SACs utilizing a photocatalytic radical control strategy. Notably, we demonstrate for the first time that radicals generated during the photochemical process effectively hinder the aggregation of individual atoms. By leveraging the cooperative anchoring of nitrogen atoms and crystal lattice oxygen on the support, we successfully stabilize the single atom. Our Pd1 /TiO2 catalysts exhibit remarkable catalytic activity and stability in the Suzuki-Miyaura cross-coupling reaction, which was 43 times higher than Pd/C. Furthermore, we successfully depose Pd atoms onto various substrates, including TiO2 , CeO2 , and WO3 . The photocatalytic radical control strategy can be extended to other single-atom catalysts, such as Ir, Pt, Rh, and Ru, underscoring its broad applicability.

Herein, we report an unprecedented regiospecific oxidative Mizoroki-Heck type reaction for the synthesis of α-difluoromethyl homoallylic alcohols. The reaction shows broad substrate scopes and high functional group tolerance. Late-stage functionalization of complex biologically active molecules demonstrates the synthetic potential of this transformation. Mechanistic study supports the involvement of MnBr2 catalyzed radical 1,2-silyl transfer.

Various alkene difunctionalization reactions involving nitridization, diamination, azidation, oxyamination, carboamination, aminohalogenation, and nitration are introduced in this review.

Controlling the reactivity of reactive intermediates is essential to achieve selective transformations. Due to the facile 1,5-hydrogen atom transfer (HAT), alkoxyl radicals have been proven to be important synthetic intermediates for the δ-functionalization of alcohols. Herein, we disclose a strategy to inhibit 1,5-HAT by introducing a silyl group into the α-position of alkoxyl radicals. The efficient radical 1,2-silyl transfer (SiT) allows us to make various α-functionalized products from alcohol substrates. Compared with the direct generation of α-carbon radicals from oxidation of α-C-H bond of alcohols, the 1,2-SiT strategy distinguishes itself by the generation of alkoxyl radicals, the tolerance of many functional groups, such as intramolecular hydroxyl groups and C-H bonds next to oxygen atoms, and the use of silyl alcohols as limiting reagents.

Herein, we disclose the first and simple one-pot-two-step process to the synthesis of 1-difluoromethyl 1,4-diketones, through Mn-catalyzed radical Brook rearrangement. The methodology is also amenable to the synthesis of 1-trifluoromethyl 1,4-diketones. The products are efficiently converted to fluoroalkyl substituted furans, thiophenes, pyrroles and pyridazines, which are important structural motifs in natural products and pharmaceuticals.

Trifluoroethanol and difluoroethanol units are important motifs in bioactive molecules, but the methods to direct incorporate these units are limited. Herein, we report two organosilicon reagents for the transfer of trifluoroethanol and difluoroethanol units into molecules. Through intramolecular C-Si bond activation by alkoxyl radicals, these reagents were applied in allylation, alkylation and alkenylation reactions, enabling efficient synthesis of various tri(di)fluoromethyl group substituted alcohols. The broad applicability and general utility of the approach are highlighted by late-stage introduction of these fluoroalkyl groups to complex molecules, and the synthesis of antitumor agent Z and its difluoromethyl analog Z′.

A new efficient protocol for the ortho‐methylation of benzamides with DTBP has been developed via Ni(II)‐catalyzed C–H activation directed by 8‐aminoquinoline. This method is performed under base‐free, ligand‐free conditions and utilizes cheap and commercially available reagents. Moreover, the by‐product acetone derived from DTBP does not affect the purification of the product.

An efficient and mild protocol for the direct conversion of arene C-H bonds to C-NH2 without the need for extra deprotection step has been established, and to the best of our knowledge, this is the first time that the synthesis of primary anilines via nickel-mediated C(sp(2))-H activations has been reported. This approach utilizes 8-aminoquinoline as the directing group and sodium azide, a cheap and commercially available material, as the nitrogen source. In addition, the reaction is highly selective, affording the mono-ortho-aminated benzamides only. The reaction tolerates a broad range of substrates with diverse functional groups and the corresponding ortho-aminated benzamides were efficiently synthesized in 41-82% yields.

An efficient nickel-promoted selective monocyanation of benzamides with TMSCN via 8-aminoquinoline directed ortho C-H activation has been developed. Varieties of functionalized ortho-cyanated (hetero)aryl nitriles can be selectively synthesized in moderate to good yields. These cyanation products can be easily transformed into various 3-imino-1-oxoisoindolines in a one-pot procedure. The mild reaction conditions, use of cheap and commercially available reagents, wide functional group tolerance, and operational convenience make this protocol practical to the synthetic community.

An efficient protocol for the synthesis of internal aryl alkynes was achieved via Cu-catalyzed decarboxylative cross-coupling reactions, and to the best of our knowledge, this is the first example of a Cu-catalyzed decarboxylative alkynylation of benzoic acids with terminal alkynes. This approach utilizes simple Cu salt as catalyst and O2, an abundant, clean, and green material, as the oxidant. The reaction tolerates various functional groups, and a variety of internal aryl alkynes were synthesized in 46-83% yields.

A novel way of synthesizing alkylated oxindoles via Cu-mediated atom transfer radical addition reaction between N-phenylacrylamides and ethyl 2-bromo-2-methylpropionate has been described. It was found that the use of N,N,N',N'-1,1,2,2,-tetramethylethylenediamine as ligand was important for achieving good yields. Additionally, the use of DMSO as solvent and running the reaction at 130 degrees C were also crucial. In some cases, the product can be further brominated when the reaction temperature was raised to 150 degrees C. (C) 2018 Elsevier Ltd. All rights reserved.

A novel copper-catalyzed decarboxylative methylthiolation of arenecarboxylate salts has been realized using DMSO as the methylthiolation source. Various potassium aryl carboxylates underwent decarboxylative methylthiolation under air to furnish the corresponding aryl methyl thioethers in moderate to excellent yields. The reaction tolerated a wide variety of functional groups. Notably, the synthesis of ethylthioethers was also successfully achieved directly from diethyl sulfoxide under similar reaction conditions.

Efficient and selective syntheses of 3-hydroxyimino-1-isoindolinones and 3-methylene-1-isoindolinones were achieved via 8-aminoquinoline assisted Cu-promoted coupling of benzamides with nitroalkanes. The reaction was found to go through C-H activation, nitroalkylation followed by intramolecular cyclization. 3-Hydroxyimino-1-isoindolinones were obtained with nitromethane whereas 3-methylene-1-isoindolinones were produced with higher nitroalkanes.

A highly efficient synthesis of 4-benzylpyridines was developed via Pd-catalyzed C(sp(3))-H arylation between 4-picoline and aryl halides. It was found that the best yields were achieved with a simple Pd(PPh3)(4) catalyst and Cs2CO3 as the base. Compared with the known methods, our reaction does not require the use of a strong organometallic reagent as the base.