Bismuth‐Mediated Diastereoselective Allylation Reaction of Carbonyl Compounds with Cyclic Allylic Halides or Cinnamyl Halide

Dissolving Microneedle Patches Integrating Optical Clearing and Photothermal Agents for Improved Photothermal Disinfection

Photothermal disinfection is an emerging and efficient therapeutic method for treating various infections. However, the therapeutic efficacy is hindered by the poor tissue penetration of light. While tissue optical clearance technology can enhance light transmission, the stratum corneum impedes the delivery of clearing agents to deeper tissues. Herein, dissolving microneedle (DMN) patches incorporating optical clearing and photothermal agents are developed for improved photothermal disinfection. Such DMN patches are obtained using sucrose as the optical clearing agent and polydopamine (PDA) nanoparticles as photothermal agents in poly(vinyl alcohol) (PVA) DMN matrix. After treatment with the composite DMN, the light transmittance of the pigskin increased by 4.75 times. The composite DMNs deliver PDAs to the subsurface of skin while improving the optical clearing effect, raising the temperature of the subsurface of pigskin to 45 °C under near-infrared (NIR) light irradiation with a wavelength of 808 nm. In treating a deep infection model (pigskin coverage) established on mouse skin, the composite DMNs significantly improve the wound recovery rate. This approach is expected to be a general strategy for enhancing the anti-infective efficacy of photothermal disinfection and shows great potential for improving the clinical application of various phototherapies.

Direct Cross-Couplings of Aryl Nonaflates with Aryl Bromides under Nickel Catalysis

The direct cross-couplings of aryl nonaflates with aryl bromides could be successfully accomplished by utilizing nickel as the catalyst, magnesium as the metal mediator, and lithium chloride as the additive. The reactions proceeded efficiently in THF at room temperature to produce the desired biaryls in moderate to good yields, showing both a reasonable substrate scope and functional group tolerance. Additionally, an equally good performance could be realized when the reaction was subjected to scale-up synthesis. Preliminary study suggested that the reaction presumably proceeds through the in situ formation of an arylmagnesium reagent as the key reaction intermediate.

Mechanisms of Activating Agents to Form Organozinc Reagents from Zinc Metal: Lessons for Reaction Design

Activating agents enable the efficient preparation of organozinc complexes from zinc metal and organohalides, but their mechanisms had been obscured by the heterogeneous nature of these systems. Fluorescence microscopy, with the sensitivity to detect surface reaction intermediates, reveals distinct activating mechanisms of widely used activation strategies: trimethylsilyl chloride, LiCl, DMSO, and Rieke zinc powder. The resulting development of mechanistic models provides a better understanding of the oxidative-addition-solubilization sequence in organozinc reagent formation and contains lessons for methods development.

Magnesium-Mediated Cross-Electrophile Couplings of Aryl 2-Pyridyl Esters with Aryl Bromides for Ketone Synthesis through In Situ-Formed Arylmagnesium Intermediates

Aryl 2-pyridyl esters could efficiently undergo cross-electrophile couplings with aryl bromides with the aid of magnesium as a reducing metal in the absence of a transition-metal catalyst, leading to the unsymmetrical diaryl ketones in modest to good yields with wide functionality compatibility. In addition, the reaction could be easily scaled up and applied in the late-stage modification of biologically active molecules. Preliminary mechanistic study showed that the coupling reaction presumably proceeds through the in situ formation of arylmagnesium reagents as key intermediates.

Bi(III)-Catalyzed Michael Addition of Tautomerizable Heterocycles with α,β-Unsaturated Carbonyl Compounds: Regioselective Construction of C-N Bonds

A Bi(III)-catalyzed synthetic strategy for regioselective construction of C-N bonds via a simple Michael addition reaction is reported. A wide range of tautomerizable heterocycles such as benzoxazolones, benzothiazolones, benzimidazolinones, indolinones, and 2-pyridones along with α,β-unsaturated carbonyls (ketones and esters) are employed to create a library of corresponding N-alkylated derivatives exclusively. High regioselectivity, high atom economy, and the participation of a range of tautomerizable heterocycles highlight the uniqueness and generality of the developed methodology.

Nickel-Catalyzed Direct Cross-Coupling of Aryl Thioether with Aryl Bromide

A straightforward cross-coupling of aryl thioether with aryl bromide with the aid of nickel salt, magnesium, and lithium chloride in tetrahydrofuran at ambient temperature was accomplished. The one-pot reactions proceeded efficiently via C-S bond cleavage to produce the desired biaryls in modest to good yields, avoiding the use of pregenerated or commercial organometallic reagents.

Nickel-Catalyzed Direct Cross-Coupling of Aryl Sulfonium Salt with Aryl Bromide

The direct cross-couplings of aryl sulfonium salts with aryl halides could be achieved by using nickel as a reaction catalyst. The reactions proceeded efficiently via C-S bond activation in the presence of magnesium turnings and lithium chloride in THF at ambient temperature to afford the corresponding biaryls in moderate to good yields, potentially serving as an attractive alternative to conventional cross-coupling reactions employing preprepared organometallic reagents.

Palladium-catalyzed direct reductive cross-coupling of aryltrimethylammonium salts with aryl bromides

Palladium-catalyzed direct reductive cross-coupling of aryltrimethylammonium salts with aryl bromides proceeded efficiently in a one-pot manner in the presence of Mg turnings, LiCl, and TMEDA in THF to afford the corresponding biaryl compounds.

Nickel-catalyzed direct cross-coupling of heterocyclic phosphonium salts with aryl bromides

The cross-couplings of heterocyclic phosphonium salts with aryl bromides proceeded effectively in the presence of nickel(ii) catalyst, bipyridine ligand, magnesium, and LiCl, providing an easy entry to 4-arylated pyridines, quinolines, and pyrazines.

Stereoselective synthesis of fluoroalkylated (Z)-alkene via nickel-catalyzed and iron-mediated hydrofluoroalkylation of alkynes

An efficient nickel-catalyzed, iron-mediated hydrofluoroalkylation of alkynes with bromodifluoroacetate or perfluoroalkyl iodide, which proceeded smoothly to give fluoroalkylated (Z)-alkenes with high stereocontrol (up to 99 : 1 Z/E), was developed.

Iron(0)-Mediated Reformatsky Reaction for the Synthesis of β-Hydroxyl Carbonyl Compounds

An efficient, economical, and practical Reformatsky reaction of α-halo carbonyl compounds with aldehydes/ketones by using cheap and commercial iron(0) powder as reaction mediator is developed. The reactions proceeded effectively in the presence of a catalytic amount of iodine (20 mol %) to afford the synthetically useful β-hydroxyl carbonyl compounds in moderate to good yields.

Iron-mediated highly diastereoselective allylation of carbonyl compounds with cyclic allylic halides

An efficient iron-mediated highly diastereoselective allylation reaction of carbonyl compounds with cyclic allylic halides using a catalytic amount of bismuth(iii) chloride is reported.