Enantioselective synthesis of chiral quinohelicenes through sequential organocatalyzed Povarov reaction and oxidative aromatization.

Heterohelicenes are of increasing importance in the fields of materials science, molecular recognition, and asymmetric catalysis. However, enantioselective construction of these molecules, especially by organocatalytic methods, is challenging, and few methods are available. In this study, we synthesize enantioenriched 1-(3-indol)-quino[n]helicenes through chiral phosphoric acid-catalyzed Povarov reaction followed by oxidative aromatization. The method has a broad substrate scope and offers rapid access to an array of chiral quinohelicenes with enantioselectivities up to 99%. Additionally, the photochemical and electrochemical properties of selected quinohelicenes are explored.

Enantioselective Synthesis of Planar-Chiral Macrocycles through Asymmetric Electrophilic Aromatic Amination.

An efficient approach for asymmetric synthesis of planar-chiral macrocycles (paracyclophanes) has been disclosed through enantioselective electrophilic aromatic aminations with azodicarboxylates enabled by chiral phosphoric acid catalysis. A wide range of chiral macrocycles bearing varied ring sizes (16 to 23-membered) and functional group-containing ansa chains were readily afforded using this method, with excellent yields and high enantioselectivities (23 examples, up to 99.5 : 0.5 er). Experimental studies and DFT calculations were performed to elucidate the mechanism and origin of stereoselectivities of these reactions. Preliminary utilization of the planar-chiral macrocycle as chiral organocatalyst showcased the potential applications of these novel chiral skeletons.

Asymmetric Synthesis of N-N Axially Chiral Compounds by Phase-Transfer-Catalyzed Alkylations.

N-N axially chiral skeletons are significant structural motifs in natural products, pharmaceuticals, and functional materials. Herein we disclose a method for the asymmetric synthesis of N-N axially chiral compounds by phase-transfer catalysis. A wide range of N-N axially chiral quinazolinone derivatives were prepared in high yields with excellent stereoselectivities. Furthermore, the synthetic utility of the protocol was proved by large-scale reaction and transformation of the product. Density functional theory calculations provide insight into the mechanism.

High-concentration glucose enhances invasion in invasive ductal breast carcinoma by promoting Glut1/MMP2/MMP9 axis expression.

Type 2 diabetes mellitus (T2DM) has been considered to be a risk factor for numerous human cancers. Hyperglycemia is one of the most direct internal environmental changes for patients with T2DM. Increasing evidence reveals that a high concentration of glucose can promote tumor progression, while its role for migration and invasion of invasive ductal breast carcinoma (IDBC) cells remains unclear. In the present study, it was demonstrated that IDBC patients with T2DM suffered an increased tumor size and more frequent lymphatic and distant metastasis compared with those without T2DM (P<0.05). MCF-7 breast carcinoma cells, which were cultured in a high glucose concentration medium (25.00 mM), exhibited increased invasion (P<0.05). In addition, the expression of glucose transporters (Gluts), matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) in IDBC tissues with T2DM was significantly higher compared to those without T2DM. Downregulation of glucose transporter 1 (Glut1) by small interfering RNA may markedly suppress MCF-7 cell invasion as well as the expression of MMP2 and MMP9. These results suggest that T2DM can affect the malignant features of tumors in IDBC. The high glucose concentration in the tumor microenvironment may enhance IDBC invasion via upregulating Glut1/MMP2/MMP9 axis expression.