AlCl3-catalyzed [3 + 3] intermolecular cycloaddition of enones with enamines is described. This efficient protocol was successfully achieved to give 1,3-cyclohexadiene derivatives in good to excellent yields.

A unique and efficient approach has been developed for the synthesis of substituted imidazo[1,2-a]pyridines with aminopyridines and chalcones via a one-pot I2-induced aerobic oxidative coupling. The reported reaction proceeded though a tandem Michael addition followed by an intramolecular oxidative amination with high regioselectivity, yields and good functional group tolerance.

In this work, a novel coumarin fluorescent sensor for Fe3+ and the pH change in DMSO was successfully prepared, and the spectra properties of the sensor a and especially its activity to metal ions, were also investigated This sensor showed an extreme selectivity and sensitivity to Fe3+ compared with other competing metal ions through fluorescence quenching in DMSO, which formed a 2:1 complex with Fe3+ and displayed fluorescent quenching. Furthermore, the binding mechanism was studied by the binding stoichiometry and DFT calculation, and the quenching mechanism was also confirmed by Mulliken's charge distribution which was calculated by quantum chemistry.

A novel approach for the synthesis of a variety of polysubstituted trans-2,3-dihydropyrroles from a wide range of chalcones and β-enamine ketones (esters) via iodine-promoted tandem Michael/cyclization sequence has been developed, affording the desired products in moderate to excellent yields. This methodology is a highly efficient, convenient way to access functionalized 2,3-dihydropyrroles from readily accessible substrates under mild reaction conditions.

•Novel isatin-phenylhydrazone dyes and their boron complexes were synthesized.•These dyes exhibit low fluorescent intensity in solution but high in solid state.•These dyes exhibit the aggregation-induced emission enhancement characteristics.•The fluorescent intensity of the BF2-complexes was stronger than the precursors.Isatin-phenylhydrazone derivatives and their corresponding BF2 complexes were efficiently synthesised by a three-step reaction starting from isatin and phenylhydrazine hydrochloride. The fluorescence properties of the isatin-phenylhydrazone derivatives and derived BF2 complexes were investigated in different organic solvents, in the solid state and in mixed solvent solutions of THF and H2O. These fluorescent dyes exhibited low fluorescent intensity in solution but a high fluorescent intensity as aggregates and in their solid state due to the interesting aggregation-induced emission enhancement characteristics which were caused by the inhibition of intramolecular rotation in the single molecule state. Information supporting this inference was supported by single crystal X-ray analysis.The isatin-phenylhydrazone derivatives and derived BF2 complexes exhibited low fluorescent intensity in solution but a high fluorescent intensity as aggregates and in their solid state due to the interesting aggregation-induced emission enhancement characteristics which were caused by the inhibition of intramolecular rotation in the single molecule state.Figure optionsDownload full-size imageDownload as PowerPoint slide

A novel KI/TBHP-catalyzed 1,3-dipolar cycloaddition/oxidation/aromatization cascade reaction provided general, efficient and green access to biologically important pyrrolo[2,1-a]isoquinolines. The product pyrrolo[2,1-a]isoquinolines were obtained from reactions between simple, readily available dipolarophiles and tetrahydroisoquinolines in moderate to excellent yields The reaction was environmentally benign in the adoption of nontoxic KI as a catalyst and IOH was generated in situ from the oxidation reaction of KI and TBHP.

A useful method for a molecular iodine induced 1,3-dipolar cycloaddition/oxidative aromatization sequence to construct 2-substituted-benzo[f]isoindole-1,3-dicarboxylates is reported. This is the first report of a molecular iodine induced 1,3-dipolar cycloaddition between quinone structures and diethyl N-substituted iminodiacetates.

We report a novel molecular iodine-catalyzed 1,3-dipolar cycloaddition/oxidation/aromatization cascade process with hydrogen peroxide as the terminal oxidant for the construction of pyrrolo[2,1-a]isoquinolines. The product pyrrolo[2,1-a]isoquinolines were obtained from reactions between simple, readily available dipolarophiles and tetrahydroisoquinolines in moderate to excellent yields without the need for a metal catalyst.

A novel and efficient synthesis of benzo[f]isoindole-4,9-diones through the I2-promoted cyclization reaction of N-substituted amino acid esters and quinones has been realized successfully via an unprecedented 1,3-dipolar cycloaddition using KF as the base. Different substituted amino esters were found able to react with quinones through a cycloaddition reaction to afford 2-substituted benzo[f]isoindole-4,9-diones. The unexpected, short, attractive and direct synthesis of these interesting compounds is important and relevant, and provides an extremely preferable method for the synthesis of 2-substituted benzo[f]isoindole-4,9-diones.

An I2-induced 1,3-dipolar cycloaddition reaction has been developed for the synthesis of benzo[f]isoindole-1,3-dicarboxylates from quinones and N-substituted amino esters. The reaction proceeds in good to excellent yields in one step from 3 equiv of amino ester to react with the quinone structure. The utility of this transformation has been highlighted by its use for the construction of benzo[f]isoindole-1,3-dicarboxylates, which have been identified in natural products exhibiting important biological activities.

Under the high-speed vibration milling conditions, the solvent and catalyst-free azo-Michael addition of chalcone derivatives and amines was found to proceed efficiently in excellent yields at ambient temperature in short reaction time. In most cases, conventional side reactions were avoided and thus quantitative yields were achieved. The influences of the vibration frequency and reaction time on the azo-Michael addition were investigated.

An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals. Various substituted toluenes (NO2, Cl, Br, H, CH3) were high selectively brominated at the benzyl position for monobromination in CH2Cl2 at ice water with catalyst free. This simple but effective bromination of toluene derivatives with an aqueous H2O2–HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.