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The functionalization of indoles in the carbocyclic ring has been achieved via organocatalytic enantioselective Friedel–Crafts benzhydrylation of hydroxyindoles with in situ generated ortho-quinome...

A fast and highly enantioselective chlorination of 4-pyrazolones catalyzed by bis(oxazoline)–Cu(ClO4)2·6H2O complexes has been developed. Under the optimized conditions, a series of pyrazolones bearing stereogenic chlorine-attached carbon centers were obtained in moderate to high yields (up to 98%) and with enantioselectivities of up to 98% ee.

A chiral amine squaramide catalyzed the conjugated addition of pyrazolin-5-ones to in situ generated ortho-quinomethanes (o-QMs) was developed to construct 4-tetrasubstituted pyrazolin-5-ones featuring adjacent quaternary and tertiary stereocenters in oil–water phases. High yields, excellent stereoselectivities, mild conditions and accessible scale-up demonstrated the fascination of this reaction protocol.

A highly regioselective and enantioselective N-alkylation of isoxazol-5-ones with para-quinone methides promoted by bi-functional squaramide catalysts was developed. This unexpected asymmetric N-addition of isoxazolinones afforded a series of enantioenriched N-diarylmethane substituted isoxazolinones with high yields and enantioselectivities (up to 97 : 3 er). This reaction not only provides a useful approach for intermolecular chiral C–N bond formation but also demonstrates the immense potential of isoxazol-5-ones as N-nucleophiles in catalytic asymmetric reactions.

Enhancement of the interfacial structure has great significances in achieving polymer blends with high mechanical performance. To improve the mechanical properties of poly( l -lactide) (PLLA)/poly(propylidene carbonate) (PPC) blends, the covalent functionalized graphene oxide by PLLA chains (PLLA-g-GO) was synthesized by a two-step strategy. It could migrate from the thermally preferred PPC phase to the interfaces of PLLA and PPC and promote the formation of a network-like structure. As a consequence, the tensile strength and elongation at break were both improved. Furthermore, the PLLA-g-GO located at the interface could induce the crystallization at the boundary, which brought the significant improvement of the tensile strength and elongation at break. This result may be beneficial for designing high-performance PLLA materials.

Fully biodegradable blends with low shape memory recovery temperature were obtained based on poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC). By virtue of their similar chemical structures, in situ cross-linking reaction initiated by dicumyl peroxide (DCP) between PLA and PPC chains was realized in PLA/PPC blends. Therefore, the compatibility between PLA and PPC was increased, which obviously changed the phase structures and increased the elongation at break of the blends. The compatibilized blends had a recovery performance at 45 °C. Combining the changes of phase structures, the mechanism of the shape memory was discussed. It was demonstrated that in situ compatibilization by dicumyl peroxide was effective to obtain eco-friendly PLA/PPC blends with good mechanical and shape memory properties.