Fei Wang

With the concept of sustainable development gaining increasing traction, the high-value utilization of forest biomass has received growing attention. In this study, an acorn-based wood adhesive was developed using Quercus fagaceae, offering a sustainable alternative that not only supports the multifunctional use of acorn shell resources, but also reduces dependence on fossil-based materials in traditional wood adhesives, a development of significant importance to the wood industry. The effects of various crosslinking agents and phenolic resin (PF) additions on the performance of the acorn-based adhesive (AS) were investigated. Among the crosslinking agents tested, isocyanate (MDI), epoxy resin E51, and trimethylolpropane diglycidyl ether (TTE), PF demonstrated the best bonding performance. The modified AS adhesive with a 30% PF addition showed the highest bonding strength (0.93 MPa) and superior water resistance. These improvements are attributed to the formation of a stable, multi-dimensional crosslinked network structure resulting from the interaction between gelatinized starch molecules and PF resin. Moreover, the AS-PF adhesive exhibited a remarkably low formaldehyde emission of 0.14 mg/L, representing a 90.67% reduction compared to the national E1 standard. The incorporation of PF also enhanced the adhesive’s mildew resistance and toughness. These findings highlight the potential of acorn-based adhesives as a sustainable alternative for applications in the wood and bamboo industries.

We report a formal carbon–carbon (C−C) bond insertion via the reaction of secondary benzylic halides (fluorides, chlorides, and bromides) with α‐diazo esters catalyzed by Lewis acid catalysts. Secondary benzylic halides underwent elongation to afford α,β‐diaryl‐β‐haloesters diastereoselectively. Density functional theory calculation revealed that the present formal C−C bond insertion was the result of Lewis acid‐promoted cleavage and the re‐formation of a carbon–halogen bond and that the aryl‐migration step determined the diastereoselectivity. Various diarylmethyl halides and α‐diazo esters were applicable to this reaction system. In addition, ring expansion in cyclic benzylic chlorides was accomplished.

We report a formal carbon–carbon (C−C) bond insertion via the reaction of secondary benzylic halides (fluorides, chlorides, and bromides) with α‐diazo esters catalyzed by Lewis acid catalysts. Secondary benzylic halides underwent elongation to afford α,β‐diaryl‐β‐haloesters diastereoselectively. Density functional theory calculation revealed that the present formal C−C bond insertion was the result of Lewis acid‐promoted cleavage and the re‐formation of a carbon–halogen bond and that the aryl‐migration step determined the diastereoselectivity. Various diarylmethyl halides and α‐diazo esters were applicable to this reaction system. In addition, ring expansion in cyclic benzylic chlorides was accomplished.

One-carbon-unit insertion into carbon–halogen (C–X) bonds accompanied by the formation of a new C–X bond and carbon–chain elongation is a powerful synthetic method of complex organohalides. Herein, we developed an indium trihalide catalyzed formal insertion of diazo esters into a C–X (X = Cl, Br, I) bond. In the present system, the reactions of α-aryl diazo esters with benzylic chlorides, bromides, and iodides yielded α-chloro, α-bromo, and α-iodo esters, respectively.

Selective transformation of C–F bonds remains a significant goal in organic chemistry, but C–F insertion of a one-carbon-atom unit has never been established. Herein we report the BF₃-catalyzed formal insertion of diazo esters as one-carbon-atom sources into C–F bonds to accomplish one-carbon elongation of benzylic fluorides. A DFT calculation study revealed that the BF₃ catalyst could contribute to both C–F bond cleavage and re-formation. This elongation provided α-fluoro-α,β-diaryl esters with a high level of diastereoselectivity. Various benzylic fluorides and diazo esters were applicable. The synthetic utility of this method was demonstrated by the synthesis of a fluoro analogue of a compound that is used as a transient receptor and potential canonical channel inhibitor.