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Herein, we disclose a visible-light-induced oxy-alkynylation of diazo compounds with ethynylbenziodoxolones. The efficient protocol provides a mild and metal-free methodology to synthesize propargylic esters in moderate to good yields. Notably, this metal-free carbene transfer reaction appears to involve an oxonium ylide intermediate, followed by intramolecular ligand exchange and reductive elimination.

Engineered wound dressing materials with excellent injectability, self-healing ability, tissue-adhesiveness, especially the ones possessing potential therapeutic effects have great practical significance in healthcare. Herein, an injectable quaternary ammonium chitosan (QCS)/tannic acid (TA) hydrogel based on QCS and TA was designed and fabricated by facile mixing of the two ingredients under physiological conditions. In this system, hydrogels were mainly cross-linked by dynamic ionic bonds and hydrogen bonds between QCS and TA, which endows the hydrogel with excellent injectable, self-healing, and adhesive properties. Benefitting from the inherent antioxidative, antibacterial, and hemostatic abilities of TA and QCS, this hydrogel showed superior reactive oxygen species scavenging activity, broad-spectrum antibacterial ability, as well as rapid hemostatic capability. Moreover, the QCS/TA2.5hydrogel (containing 2.5% TA) exhibited excellent biocompatibility. The in vivo experiments also showed that QCS/TA2.5hydrogel dressing not only rapidly stopped the bleeding of arterial and deep incompressible wounds in mouse tail amputation, femoral artery hemorrhage, and liver incision models but also significantly accelerated wound healing in a full-thickness skin wound model. For the great potentials listed above, this multifunctional QCS/TA2.5hydrogel offers a promising network as a dressing material for both rapid hemostasis and skin wound repair.

Multifunctional hydrogel as a sealant or wound dressing with high adhesiveness and excellent antibacterial activity is highly desirable in clinical applications. In this contribution, one‐step synthetic hydrogel based on quaternized chitosan (QCS), tannic acid (TA), and ferric iron (Fe(III)) is developed for skin incision closure and Staphylococcus aureus(S. aureus)‐infected wound healing. In this hydrogel system, the ionic bonds and hydrogen bonds between QCS and TA form the main backbone of hydrogel, the metal coordination bonds between TA and Fe(III) (catechol‐Fe) endow hydrogel with excellent adhesiveness and (near‐infrared light) NIR‐responsive photothermal property, and these multiple dynamic physical crosslinks enable QCS/TA/Fe hydrogel with flexible self‐healing ability and injectability. Moreover, QCS/TA/Fe hydrogel possesses superior antioxidant, anti‐inflammatory, hemostasis, and biocompatibility. Also, it is safe for vital organs. The data from the mouse skin incision model and infected full‐thickness skin wound model presented the high wound closure effectiveness and acceleration of the wound healing process by this multifunctional hydrogel, highlighting its great potential in wound management. Multifunctional QCS/TA/Fe hydrogel based on quaternized chitosan (QCS), tannic acid (TA), and ferric iron (Fe(III)) with well antioxidant, (near‐infrared light) NIR‐responsive photothermal antibacterial, adhesive, conductive, self‐healing, hemostasis, injectable, and biocompatible properties is prepared by one step method and used for the closure of full‐thickness mouse skin model and the healing of infected full‐thickness skin wound model.