Central-to-Folding Chirality Control: Asymmetric Synthesis of Multilayer 3D Targets With Electron-Deficient Bridges

Abstract

New multilayer 3D chiral molecules have been designed and synthesized asymmetrically through the strategy of center-to-multilayer folding chirality control and double Suzuki couplings. Individual diastereoisomers were readily obtained and separated via flash column chromatography. The key diastereoisomer was further converted into corresponding enantiomers. These enantiomers possess electron-deficient aromatic bridges layered with top and bottom aromatic scaffolds. X-ray structural analysis has unambiguously confirmed the configuration, and intermolecular packing results in regular planar patterns in solid crystals. The synthesis was achieved in a total of ten steps starting from commercially available starting materials.

A new chiral phenomenon of orientational chirality, its synthetic control and computational study

“…Since there is only a single interaction (the heavy black line in the model, Figure 8B) existing in each of the three atropisomers, there are three energy barriers instead of six in the previous atropisomerism to be expected. It should be pointed out that the nomenclature of previous molecular architectures follows the Cahn−Ingold−Prelog (CIP) rules (Tang et al, 2022b;Jin et al, 2022). However, finding a nomenclature rule for the present chirality framework seems difficult.…”

“…It should be pointed out that the nomenclature of previous molecular architectures follows the Cahn−Ingold−Prelog (CIP) rules ( Tang et al, 2022b ; Jin et al, 2022 ). However, finding a nomenclature rule for the present chirality framework seems difficult.…”

“…Meanwhile, pseudo or quasi C 2 symmetry has also become an interesting and important addition to chirality documents. For instance, organo sandwich chirality shows unique “S” and “Ƨ” ( anti S) patterns of pseudo C 2 symmetry ( Tang et al, 2022b ; Jin et al, 2022 ), and their chiral aggregates displayed various spectroscopic properties ( Figure 2 ).…”

Four-layer folding framework: design, GAP synthesis, and aggregation-induced emission

“…In the past several years, our group has reported new multi-layer folding chirality of a series of molecules, including oligomers and polymers with structural flexibility, displaying physical properties on UV/Vis absorption, fluorescence, electrochemical performance, aggregation-induced emission (AIE) ( Wu et al, 2019 ; Wu et al, 2019 ; Liu et al, 2020 ; Wu et al, 2020 ; Wu et al, 2021a ; Jin et al, 2022a ; Tang et al, 2022a ; Tang et al, 2022b ; Wang et al, 2022 ), and aggregation-induced polarization (AIP) ( Tang et al, 2022c ; Tang et al, 2022d ). Among them are three-layer compounds ( Scheme 1 ), in which electron-rich ( Tang et al, 2022b ) and electron-deficient ( Jin et al, 2022a ) bridges showed distinct impacts on UV–vis absorption and fluorescence behaviors. It is worth noting that many of these compounds showed fluorescence not only in solutions but also in solid states.…”

Aggregation-Induced Polarization (AIP): Optical Rotation Amplification and Adjustment of Chiral Aggregates of Folding Oligomers and Polymers

“…The origin of AIE was made possible by restricting intramolecular motions (rotation and vibration) which limit or avoid aggregation-caused quenching (ACQ) of conventional luminophores. During our ongoing projects on multiple-layered 3D folding chirality, we found that chiral aggregates of folding monomers, oligomers, and polymers displayed strong AIE by gradually increasing water fractions (f w ) in THF-H 2 O cosolvents (Wu et al, 2019;Liu et al, 2020;Wu et al, 2020;Wu et al, 2021a;Wu et al, 2021b;Tang et al, 2022b;Jin et al, 2022;Wang et al, 2022). Interestingly, we also found these polymers showed AIE curves bounding when f w was increased to 70%, which contrast with the observation of their monomer derivatives (Wu et al, 2021b;Wang et al, 2022).…”