Cu-Catalyzed Asymmetric Dicarboxylation of 1,3-Dienes with CO2.

Dicarboxylic acids and derivatives are important building blocks in organic synthesis, biochemistry, and the polymer industry. Although catalytic dicarboxylation with CO2 represents a straightforward and sustainable route to dicarboxylic acids, it is still highly challenging and limited to generation of achiral or racemic dicarboxylic acids. To date, catalytic asymmetric dicarboxylation with CO2 to give chiral dicarboxylic acids has not been reported. Herein, we report the first asymmetric dicarboxylation of 1,3-dienes with CO2 via Cu catalysis. This strategy provides an efficient and environmentally benign route to chiral dicarboxylic acids with high regio-, chemo-, and enantioselectivities. The copper self-relay catalysis, that is, Cu-catalyzed boracarboxylation of 1,3-dienes to give carboxylated allyl boronic ester intermediates and subsequent carboxylation of C-B bonds to give dicarboxylates, is key to the success of this dicarboxylation. Moreover, this protocol exhibits broad substrate scope, good functional group tolerance, easy product derivatizations, and facile synthesis of chiral liquid crystalline polyester and drug-like scaffolds.

SNP and mRNA expression for glutathione peroxidase 4 in Kashin-Beck disease.

Kashin-Beck disease (KBD) is a chronic endemic osteoarthropathy, which mainly occurs in West and Northeast China. Epidemiological studies suggest that Se deficiency is an important environmental factor for the incidence of KBD. Glutathione peroxidase 4 (GPx4) belongs to the glutathione peroxidase family, which is crucial for optimal antioxidant defences. Our purpose is to investigate the putative association between GPx4 polymorphisms and the risk of KBD. Restriction fragment length polymorphism-PCR was used to detect two SNP (rs713041, rs4807542) in 219 cases and 194 controls in Han Chinese subjects, and quantitative analysis for the GPx4 mRNA level was performed by the real-time PCR method. The results revealed that linkage disequilibrium existed in the two SNP. A significant difference was observed in the haplotype A-T (P = 0·0066) of GPx4, which was obviously lower in the KBD cases (0·006 v. 0·032 %). Correlation analysis based on a single locus showed no association between each SNP and KBD risk. Furthermore, the GPx4 mRNA level was dramatically lower in the blood of KBD patients. Overall, our finding indicated GPx4 polymorphisms and decreased mRNA level may be related to the development of KBD in the Chinese population, suggesting GPx4 as a possible candidate susceptibility gene for KBD.

[TrxR2 gene polymorphisms may not be associated with the susceptibility to Kashin-Beck disease].

OBJECTIVE: To study the association between single nucleotide polymorphisms of thioredoxin reductase-2 (TrxR2) gene and the susceptibility to Kashin-Beck disease (KBD). METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze the genotype frequencies of rs5748469 in TrxR2 gene in 84 KBD patients and 109 healthy control subjects. RESULTS: The genotype frequencies of A/A, A/C, and C/C in the KBD patients were 83.33%, 15.48% and 1.19%, as compared with the frequencies of 74.31%, 25.69%, and 0.00% in the healthy control, respectively, showing no significant difference in the single nucleotide polymorphisms of TrxR2 gene between the two groups (P=0.13). CONCLUSION: No obvious correlation can be found between rs5748469 polymorphisms in TrxR2 gene and the susceptibility to KBD.