Here, we report the fabrication of a dynamic enamine-one bond based vitrimer through amino-yne click chemistry. In contrast to amine-acetoacetate condensation, the amino-yne click reaction yields a dynamic enamine-one motif that is composed of cis/trans (3:1) isomers and has a relatively lower activation energy (35 ± 3 kJ/mol vs 59 ± 6 kJ/mol), owing to the absence of a methyl substituent. The resulting vitrimer network has superior mechanical properties and faster dynamic exchange than that of a reference vitrimer derived from amine-acetoacetate condensation, and they are attributed to the fewer network defects and the less sterically hindered exchange reaction, respectively. Lastly, the efficient amino-yne click reaction is demonstrated to be compatible with the secondary-amine substrate, which has a low reactivity toward the amine-acetoacetate condensation. The efficient and side product-free amino-yne reaction offers a powerful chemical tool for vitrimer fabrication and is potentially desirable for sealing and adhesion applications.

The catalytic functionalization of alkenes is among the most important and powerful methods for construction of two new bonds through cleavage of the π bonds, which is widely used for construction of numerous complex organic molecules. Recently, the strategy that involves directing groups-assisted regioselective functionalization of alkenes has found great synthetic application value, and great achievements have been made in the functionalization of unactivated alkenes and alkynes. This Minireview summarizes the recent progress in transition metal-catalyzed functionalization of unactivated alkenes and alkynes assisted by bidentate directing groups with high chemo-, regio-, and stereo-selectivity.[a] Dr. Scheme 1. Sequential carbopalladation of cyclooctadiene with a stoichiometric amount of PdCl 2 . Reproduced with permission from Ref. 8 a. . Regioselective carbopalladation of allylic amines with stoichiometric amount of Li 2 PdCl 4 . Reproduced with permission from Ref. 8 b. . Proposed mechanism of Ni(0)-catalyzed AQ-directed intermolecular 1,2-dicarbofunctionalization. Reproduced with permission from Ref. 22. Scheme 15. Ni-catalyzed three-component 1,2-dialkylation of unactivated alkenes. Reproduced with permission from Ref. 23. Scheme 16. Proposed mechanism of Ni-catalyzed three-component 1,2dialkylation of unactivated alkenes. Reproduced with permission from Ref. 23. Scheme 17. Pd(II)-catalyzed regioselective syn-hydroarylation of unactivated alkynes. Reproduced with permission from Ref. 26.

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Bio-based coating materials were prepared from epoxidized soybean oil as a renewable source. Acetoacetylated soybean oil was synthesized by the ring-opened and transesterification reaction of epoxidized soybean oil, and its chemical structure was characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and rheometric viscosity analyses. On the basis of acetoacetylated soybean oil, several bio-based coating materials were prepared using different aromatic dicarboxaldehydes (1,2-benzenedialdehyde, 1,3-benzenedialdehyde, 1,4-phthalaldehyde, 4,4′-biphenyldicarboxaldehyde) and characterized. The resulting films possess good performance, including the highest glass transition temperature of 54 °C, a Young’s modulus of 24.91 MPa, tensile strength of 5.65 MPa, and an elongation at break of 286%. Thus, this work demonstrates the Knoevenagel condensation reaction, which is based on soybean oil as a potential newer eco-friendly raw material.

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