Publications by authors named "Shangru Yang"

The rearrangement of sterically congested cyclic (amino)(aryl)carbenes (CAArCs) by the reaction of related iminium salts with potassium bis(trimethylsilyl)amide is reported, allowing for forming benzocyclobutanimines via a ring contraction process. Mechanistic studies by theoretical calculations indicate that the formation of conjugated ketenimines as intermediates could be considered, in which steric hindrance caused by -alkyl motifs of CAArCs plays an important role in promoting the ring-opening by the cleavage of C-N bond.

View Article and Find Full Text PDF

Reported here is the reductive transamidation of tertiary amides with nitroarenes promoted by main group metal magnesium and chlorosilane. The reaction uses commercially available and air-stable nitroarenes as nitrogen sources, so it can occur under transition-metal- and ligand-free conditions, thus providing a step-economic and cost-effective strategy for forming centrally important secondary amides. Several biologically interesting amide motifs are readily accessible by the Mg-promoted reductive transamidation.

View Article and Find Full Text PDF

Described here is the chromium-catalyzed cleavage of C(aryl)-SMe bonds leading to coupling with organomagnesium to give functionalized benzaldehydes under mild conditions. This reaction was promoted specifically by a low-cost and simple CrCl salt used as a precatalyst, enabling synchronous activations of -C(aryl)-SMe and '-C(aryl)-H bonds to achieve difunctionalization of benzaldimines. This work provided a strategy for accessing arylated, alkylated, and diarylated benzaldehyde derivatives as a result of the couplings of C(aryl)-SMe and C(aryl)-SMe/C(aryl)-H bonds promoted with cost-effective Cr catalysis.

View Article and Find Full Text PDF

The two-stage cultivation strategy was optimized in this study to simultaneously promote the growth and lipid accumulation of Tetradesmus obliquus. Results showed that the optimal dual-stress conditions were nitrogen concentration at 25 mg N·L and low-frequency ultrasound at 200 Watt, 1 min, and 8 h interval. The biomass and lipid content of Tetradesmus obliquus were increased by 32.

View Article and Find Full Text PDF

We report here the first example of cross-coupling between two different and unactivated C(aryl)-O bonds with chromium catalysis. The combination of a low-cost Cr(II) salt, 4,4'-di--butyl-2,2'-dipyridyl (dtbpy) as the ligand, and magnesium as the reductant shows high reactivity in promoting the reductive cross-coupling of aryl methyl ether derivatives with aryl esters by cleavage and coupling of two different C(aryl)-O bonds under mild conditions. The formation of active low-valent Cr species by reduction of CrCl with Mg can be considered, which prefers to initially activate the C(aryl)-O bond of phenyl methyl ether with the chelation help of dtbpy and an -imine auxiliary.

View Article and Find Full Text PDF

Protein ubiquitination plays an essential role in the regulation of retinoic acid-inducible gene I (RIG-I) activation and the antiviral immune response. However, the function of the opposite process of deubiquitination in RIG-I activation remains elusive. In this study, we have identified the deubiquitinating enzyme ubiquitin-specific protease 4 (USP4) as a new regulator for RIG-I activation through deubiquitination and stabilization of RIG-I.

View Article and Find Full Text PDF