NiH-catalyzed C(sp3)-Si coupling of alkenes with vinyl chlorosilanes.

A novel NiH-catalyzed highly regioselective coupling of alkenes with vinyl chlorosilanes, constructing C-Si bonds, is developed. Under mild reaction conditions, a series of benzyl organosilanes with various functional groups could be accessed. Further synthetic studies illustrate that the products of this chemistry could be used as versatile precursors to prepare complicated organosilicon compounds. Moreover, the NiH-catalyzed mechanism of the present transformation was proposed based on control experiments.

Nickel-Catalyzed Reductive Cross-Coupling of Alkyl Bromides and Chlorosilanes.

A novel nickel-catalyzed highly selective reductive cross-coupling of alkyl bromides and chlorosilanes to construct the C-Si bond has been developed. Under benign reaction conditions, a series of structurally interesting organosilanes can be accessed without Ni-catalyzed isomerization. The utility of this chemistry is illustrated by further transformations of the product. Moreover, the radical mechanism of the reaction is illustrated by control experiments.

Nickel-Catalyzed Highly Selective Hydroalkenylation of Alkenyl Boronic Esters to Access Allyl Boron.

Allyl boron derivatives are valuable building blocks in the synthesis of natural products and bioactive molecules. Herein, a practical strategy of nickel-catalyzed highly selective hydroalkenylation of alkenyl boronic esters was developed. Under the mild reaction conditions, a variety of allyl boronic esters were accessed with excellent chemo- and regioselectivity. The mechanism of this transformation was illustrated by control experiments and kinetic studies.

Human-like collagen promotes the healing of acetic acid-induced gastric ulcers in rats by regulating NOS and growth factors.

Human-like collagen (HLC), the collagen produced using fermentation technology, has been demonstrated previously to promote wound healing. However, the healing property of HLC in gastric ulcers remains to be verified. In this study, we investigated the healing efficacy and healing mechanisms of HLC on gastric ulcers. To investigate whether HLC still has healing activity on gastric ulcers after gastric digestion, we simulated gastric digestion in vitro to obtain a human-like collagen digestion product (HLCP) and used it as the control drug. A chronic gastric ulcer model induced by 60% acetic acid in rats was used to evaluate the healing effect of gastric ulcers in this study. The results showed that oral administration of HLC or HLCP for 4 or 7 days promoted ulcer healing, which can be directly observed by significant reductions in ulcer area. The oral administration of HLC and HLCP significantly increased the protein expression of growth factors (EGF, HGF, VEGF, bFGF and TGF-ß1) and the HGF receptor (HGFr), promoted collagen deposition, regulated the activity of NOS, and decreased pro-inflammatory cytokines (TNF-a, il-6, il-10) and endothelin-1 (ET-1) levels in gastric tissue. Moreover, cell experiments showed that the effects of HLC on cell proliferation and migration are mainly caused by its digestion products. These findings indicate that HLC may be used as a nutritional supplement or therapeutic drug to promote the healing of gastric ulcers.

Pd-Catalyzed Stereoselective 1,2-Aryboration of Alkenylarenes.

The palladium-catalyzed highly regio- and diastereoselective arylboration of alkenylarenes has been developed. This chemistry afforded the benzylic boronic esters with a broad substrate scope, which are valuable synthetic intermediates for organic synthesis. The chiral anion phase-transfer strategy was designed for this transformation to realize the regio-, diastereo-, and enantioselective control of this reaction simultaneously.

Cu-Catalyzed highly selective reductive functionalization of 1,3-diene using H2O as a stoichiometric hydrogen atom donor.

A copper-catalyzed highly regio- and diastereo-selective reductive reaction of terminal 1,3-diene with water and aldehyde has been developed. This chemistry afforded a product containing a terminal alkenyl group, which is a versatile kind of precursor for organic synthesis, with the scope for various substrates. The present reaction system could realize the catalytic transfer of hydrogen to diene using water as a stoichiometric H atom donor. In this transformation, B2Pin2, a mild and practical kind of reductant was used as the mediator. The reaction pathway of this practical strategy was illustrated by a control experiment.