Search

General and efficient methods are developed for the construction of five-membered aromatic and nonaromatic heterocycles by palladium-catalyzed coupling/cycloisomerization of 1,6-enynes and aryl halides. The results have shown that substituents at the terminus of the alkynes have a major impact on the selective formation of the products.

The total synthesis of (+)-frondosin A is accomplished from commercially available materials. Ru-catalyzed [5+2] cycloaddition is applied to the total synthesis of a natural product from which the absolute configuration of (+)-frondosin A is established.

Thesearch for functional supramolecular aggregations with differentstructure has attracted interest of chemists because they have thepotential in industrial and technological application. Hydrophobicinteraction has great influence on the formation of these aggregations,such as hexagonal liquid crystals, wormlike micelles, hydrogels, etc.So a systematical investigation was done to investigate the influenceof alkyl chain length of surfactants on the aggregation behavior inwater. The aggregation behavior of 1-hexadecyl-3-alkyl imidazoliumbromide and water has been systematically investigated. These ionicliquid surfactants are denoted as C16–Cn(n= 2, 3, 4, 6, 8, 9, 10, 12,14, 16). The rheological behavior and microstructure were characterizedvia a combination of rheology, cryo-etch scanning electron microscopy,polarization optical microscopy, and X-ray crystallography. The alkylchain has great influence on the formation of surfactant aggregatesin water at the molecular level. With increasing alkyl chain length,different aggregates, such as hexagonal liquid crystals, wormlikemicelles, and hydrogels can be fabricated: C16–C2aqueous solution only forms hexagonal liquid crystal; C16–C3aqueous solution forms wormlike micelleand hexagonal liquid crystal; C16–C4,C16–C6and C16–C8aqueous solutions only form wormlike micelle; C16–C9aqueous solution experiences a transition betweenwormlike micelle and hydrogel; C16–C10, C16–C12, C16–C14and C16–C16only form hydrogel.The mechanism of the transition of different aggregation with increasingalkyl chain length was also proposed. [ABSTRACT FROM AUTHOR]