A facile and general method for the preparation of chemically responsive polymer films is demonstrated. First, a crosslinked polymer precoating layer is created via self-initiated photografting and photopolymerization of ethylene glycol dimethacrylate on a self-assembled monolayer of a 3-(trimethoxysilyl)propylamine modified oxidized silicon wafer. The intact methacrylate functionalities are used to grow polymer chains by a second self-initiated photografting and photopolymerization of vinyl monomers to form polymer brushes on the crosslinked layer; thus a series of polymer membranes of PMMA, PDMAEMA and P4VP are obtained. The double-layered polymer membranes can be lifted off via hydrofluoric acid etching of the oxidized silicon layer to give integral free-standing polymer membranes. Kinetic studies revealed that the thickness of both the crosslinked precoating layer and the brush layer increased linearly as a function of the polymerization time before the reaction solutions got highly viscous. Furthermore, polyoxometalate Na9(EuW10O36) can be uniformly incorporated into the PDMAEMA membrane through electrostatic interactions to afford an acid/base gas-responsive luminescent hybrid film.

Rhodamine spirocyclic chemosensors have attracted a lot of attention due to their simplicity, high sensitivity, and real-time detection for various analytes. Among the different types of substituents, salicylidene hydrazone is a well-known component due to its electron-donating ability and adjustable coordination cavity, which has strong sensitivity to various metal ions. In this review, the fluorescent and colorimetric sensors are classified according to their recognition and sensing categories, including Cu2+ and Hg2+ sensors, other metal ions sensors (Zn2+, Fe3+, Pb2+, Cr6+, Al3+) , CN− and amino acid sensors. Salicylidene modulation with electron-donating groups is a powerful approach for fluorescence detection of metal ions with a nanomolar range, and the indirect sensing strategy is a good idea for the sensitive detection of anions and other species.

Facile and efficient synthesis of 5-iminooxazolines from α,α-disubstituted β-oximyl amides mediated by triflic anhydride (Tf2O) in the presence of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) in dichloromethane at room temperature is developed, and a mechanism involving tandem Beckmann rearrangement and intramolecular cyclization reaction is proposed.

A formal [4 + 1] annulation of readily available α-arylhydrazonoketones and trimethylsulfoxonium iodide in the presence of cesium carbonate is described involving a sequential Corey–Chaykovsky reaction and intramolecular nucleophilic cyclization process. Substituted pyrazoles were obtained exclusively from the reactions of α-arylhydrazono-β-oxo-amides and trimethylsulfoxonium iodide in moderate to good yields, whereas the reactions of α-arylhydrazono-β-oxo-ketone/α-arylhydrazono- β-oxo-ester afforded the corresponding dihydropyrazoles in good yields.

A facile and efficient one-pot synthesis of cyanoformamides was developed from readily available 1-acyl-1-carbamoyl oximes mediated by phosphoryltrichloride (POCl3) under mild conditions in good to high yields.

A facile and efficient synthesis of substituted pyridine-2,6(1H,3H)-diones via an intramolecular [5 + 1] annulation of readily available α-alkenoyl-α-carbamoyl ketene-S,S-acetals mediated by phosphorus bromide (PBr3) under very mild conditions is described.

A facile and efficient one-pot synthesis of polysubstituted pyridin-2(1H)-ones from readily available enaminones and the cyanomethyl sulfonium bromide salt in the presence of cesium carbonate is developed, and a mechanism involving sequential nucleophilic vinylic substitution (SNV), intramolecular nucleophilic cyclization and dealkylation reactions is proposed.

A novel copper-catalyzed formal O–H insertion of α-diazo-1,3-dicarbonyl compounds to carboxylic acids has been developed, providing a straightforward synthetic method for α-acyloxy-1,3-dicarbonyl compounds, in which the activation of carboxylic acids by isocyanide plays a crucial role.

An efficient and divergent one-pot synthesis of 2,3-dihydro-1H-pyrroles, 3-alkyl-1H-pyrroles and 3-alkenyl-1H-pyrroles from readily accessible 2,4-pentadienenitriles with isocyanide based on reaction condition selection has been described. The reaction of 2,4-pentadienenitriles with ethyl isocyanoacetate undergoes a formal [2 + 3] annulation either to generate 2,3-dihydro-1H-pyrroles in the presence of DBU (0.3 equiv.) in EtOH at room temperature or to give 3-alkyl-1H-pyrroles in the presence of DBU (2.0 equiv.) in EtOH under reflux. Moreover, the 2,3-dihydro-1H-pyrroles could be converted to 3-alkenyl-1H-pyrroles with DDQ as an oxidant.

An efficient one-pot synthetic route to highly substituted cyclopropanes has been developed from readily available α,β-unsaturated nitriles and doubly activated methylene compounds under very mild conditions in a highly diastereoselective manner, which involves halogenation, Michael addition and intramolecular ring-closing reaction sequences.

A facile and efficient synthesis of substituted dihydropyridone–BF2 complexes is developed via intramolecular cyclization of α-acyl acrylamides and α-acyl cinnamamides mediated by BF3·Et2O.

Regioselective synthesis of multisubstituted 4-amino- and 6-amino-2-iminopyridines has been developed via the copper-catalyzed three-component reaction based on the reaction conditions selection. The reaction of sulfonyl azides, alkynes, and 2-[(amino)methylene]malononitriles catalyzed by copper(I) iodide in tetrahydrofuran at room temperature afforded substituted 4-amino-2-iminopyridines, whereas, in N,N-dimethylformamide at 50 °C under N2, it generated substituted 6-amino-2-iminopyridines as predominant products.

A facile and efficient route for the homogeneous and highly stereoselective monohydration of substituted methylenemalononitriles to (E)-2-cyanoacrylamides catalyzed by copper(II) acetate monohydrate in acetic acid containing 2% water is described, and a mechanism is proposed. The protocol has proved to be suitable for the monohydration of dicyanobenzenes and 2-substituted malononitriles.

Facile and efficient synthesis of spiro-fused dihydrofuran-3(2H)-ones was developed via phenyliodine(III) diacetate (PIDA) mediated oxidative cyclization of 1-alkenoyl-1-carbamoyl cycloalkanes under very mild conditions.

An efficient one-pot synthetic route to highly substituted cyclopropanes has been developed from readily available α,β-unsaturated nitriles and doubly activated methylene compounds under very mild conditions in a highly diastereoselective manner, which involves halogenation, Michael addition and intramolecular ring-closing reaction sequences.

A novel copper-catalyzed formal O–H insertion of α-diazo-1,3-dicarbonyl compounds to carboxylic acids has been developed, providing a straightforward synthetic method for α-acyloxy-1,3-dicarbonyl compounds, in which the activation of carboxylic acids by isocyanide plays a crucial role.

A facile and efficient one-pot synthesis of polysubstituted pyridin-2(1H)-ones from readily available enaminones and the cyanomethyl sulfonium bromide salt in the presence of cesium carbonate is developed, and a mechanism involving sequential nucleophilic vinylic substitution (SNV), intramolecular nucleophilic cyclization and dealkylation reactions is proposed.

An efficient and divergent one-pot synthesis of 2,3-dihydro-1H-pyrroles, 3-alkyl-1H-pyrroles and 3-alkenyl-1H-pyrroles from readily accessible 2,4-pentadienenitriles with isocyanide based on reaction condition selection has been described. The reaction of 2,4-pentadienenitriles with ethyl isocyanoacetate undergoes a formal [2 + 3] annulation either to generate 2,3-dihydro-1H-pyrroles in the presence of DBU (0.3 equiv.) in EtOH at room temperature or to give 3-alkyl-1H-pyrroles in the presence of DBU (2.0 equiv.) in EtOH under reflux. Moreover, the 2,3-dihydro-1H-pyrroles could be converted to 3-alkenyl-1H-pyrroles with DDQ as an oxidant.