A deconstructive oxygenation of unstrained primary cycloalkanamines has been developed for the first time using an auto‐oxidative aromatization promoted C(sp3)−C(sp3) bond cleavage strategy. This metal‐free method involves the substitution reaction of cycloalkanamines with hydrazonyl chlorides and subsequent auto‐oxidative annulation to in situ generate pre‐aromatics, followed by N‐radical‐promoted ring‐opening and further oxygenation by 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) and m‐cholorperoxybenzoic acid (mCPBA). Consequently, a series of 1,2,4‐triazole‐containing acyclic carbonyl compounds were efficiently produced. This protocol features a one‐pot operation, mild reaction conditions, high regioselectivity and ring‐opening efficiency, broad substrate scope, and is compatible with alkaloids, osamines, and peptides, as well as steroids.

Hydrogel strain sensors have attracted tremendous attention in medical monitoring, flexible wearable devices, and human–machine interfaces. However, traditional hydrogels exhibit isotropic sensing performance based on their isotropic structure. Therefore, it is challenging to fabricate a hydrogel with an anisotropic structure similar to human tissues for achieving anisotropic sensing characteristics. Herein, we proposed a simple and effective method for preparing anisotropic poly­(vinyl alcohol) (PVA) conductive hydrogels, which demonstrated anisotropic mechanical properties and anisotropic ion conductivity. The anisotropic hydrogel was successfully constructed through first thermal stretching and then directional freezing. The mechanical strength of hydrogels along the parallel stretching direction (stress of 1596 kPa and toughness of 3.69 MJ/m3) was higher than that of the hydrogels along the vertical stretching direction (stress of 883.1 kPa and toughness of 1.96 MJ/m3). Moreover, the hydrogel showed anisotropic conductivity on the advantage of the different ion channels. The prepared hydrogel sensor exhibited anisotropic sensing for multidirectional stress in the strain range from 0.5 to 100%. The gauge factors (GF) parallel to the stretching direction were greater than the GF vertical to the stretching direction. The anisotropic hydrogel sensors are expected to have broad application prospects in flexible wearable devices and medical monitoring.

The hydrogels with optimal alkyl segments reinforced by LPs exhibited the maximum fracture stress of 1.2 MPa and elongation of 2336%.

Conductive hydrogels are ideal materials for preparing wearable strain sensing devices due to their flexibility and stretchability. However, most hydrogels exhibited poor freezing resistance and weak water-holding ability, thus hindering...

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