Catalysis direction selective asymmetric polymerization in chiral liquid crystal medium

[3+1+1] type cyclization of ClCF2COONa for the assembly of imidazoles and tetrazoles via in situ generated isocyanides

A facile synthesis of imidazoles and tetrazoles via [3+1+1] type cyclization of ClCF₂COONa is developed.

Silylium cation initiated sergeants-and-soldiers type chiral amplification of helical aryl isocyanide copolymers

Silylium cations act as new highly efficient metal-free single-component cationic initiators for the cationic polymerization and copolymerization of chiral or achiral aryl isocyanides, preparing optically active polymers and copolymers obeying “sergeants-and-soldiers” rule.

Enantiocomplementary Chiral Polyhydroxyenoate: Chemoenzymatic Synthesis and Helical Structure Control

Here, we present the chemoenzymatic synthesis of two pairs of configuration-customized unsaturated chiral polyesters and discover that they are able to self-assemble into a helical superstructure. The chiral (R)- or (S)-polyesters with a polar unsaturated main-chain and an apolar side chain were designed to be stereoregular and amphiphilic-like. The solvent polarity, stereoregularity, unsaturated bond in the backbone and the structure of side chains were found to be the key factors to affect the self-assembly performance of the chiral polyesters. As the solvent polarity increased, the nanostructures of stereoregular unsaturated polyesters transformed from spheres to helical fibers, while there was no such transformation for the racemic or saturated polyesters.

Synthesis of β-Aminoenones via Cross-Coupling of In-Situ-Generated Isocyanides with 1,3-Dicarbonyl Compounds

An efficient and practical strategy for the synthesis of β-aminoenones from a three-component reaction was developed. Ethyl bromodifluoroacetate serves as a C1 source in this strategy, forming isocyanides in situ with primary amines. This reaction represents the first example of utilization of readily available starting materials to generate isocyanides in situ and sequentially fully converted to β-aminoenones, avoiding the generation of byproduct imines and overinsertion products. The mechanism study suggested that this method involves activation of two C(sp³)-F bonds and the formation of isocyanides, which might nourish both isocyanide chemistry and fluorine chemistry.

Construction of Polymer-Stabilized Automatic MultiDomain Vertical Molecular Alignment Layers with Pretilt Angles by Photopolymerizing Dendritic Monomers under Electric Fields

The synthesized itaconic acid-based dendritic amphiphile (Ita3C₁₂) monomers and the methacryl polyhedral oligomeric silsesquioxane (MAPOSS) cross-linkers were directly introduced for the construction of automatic vertical alignment (auto-VA) layers in the host nematic liquid crystal (NLC) medium. The auto-VA layer can be stabilized by irradiating UV light. For the automatic fabrication of a polymer-stabilized multidomain VA (PS auto-MDVA) layer with a pretilt angle, Ita3C₁₂ and MAPOSS were photopolymerized under the electric field by irradiating UV light on the multidomain electrode cell. Mainly because of the pretilted NLC at zero voltage, the electro-optic properties of the PS auto-MDVA cell were dramatically improved. From the morphological observations combined with surface chemical analyses, it was found that various sizes of protrusions on the solid substrates were automatically constructed by the two-step mechanisms. We demonstrated the PS auto-MDVA cell with the enhancement of electro-optic properties as a single-step process and investigated how the protrusions were automatically developed during the polymer stabilization.

Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

In this review, we describe the recent advances in supramolecular helical assemblies formed from chiral and achiral small molecules, oligomers (foldamers), and helical and nonhelical polymers from the viewpoints of their formations with unique chiral phenomena, such as amplification of chirality during the dynamic helically assembled processes, properties, and specific functionalities, some of which have not been observed in or achieved by biological systems. In addition, a brief historical overview of the helical assemblies of small molecules and remarkable progress in the synthesis of single-stranded and multistranded helical foldamers and polymers, their properties, structures, and functions, mainly since 2009, will also be described.