Photocatalytic Hydrogenation of Alkenes Using Water as Both the Reductant and the Proton Source.

Utilization of clean and low-cost water as the reductant to enable hydrogenation of alkenes is highly attractive in green chemistry. However, this research subject is considerably challenging due to the sluggish kinetics of the water oxidation half-reaction. It is also very difficult to avoid the undesired oxidation of alkenes because that this oxidation is far easier to occur than the desired oxidation of water from thermodynamic standpoint. Herein, this challenge is overcome by applying a cooperative catalysis where HCl is used as the cocatalyst to accelerate Pt/g-C3N4-catalyzed water oxidation and suppress the undesired oxidation of the alkene. This provides an example for using water as the reductant and the proton source to enable the photocatalytic hydrogenation of alkenes. The present method exhibits broad substrate applicability, and allows various arylethenes and aliphatic alkenes to undergo the hydrogenation smoothly.

Isolation and identification of antibacterial neo-compounds from the red ants of ChangBai Mountain, Tetramorium sp.

Three novel coumarin compounds along with two known amide alkaloids were isolated from a methanol extract of the red ants of ChangBai Mountain, Tetramorium sp. Their structures were identified on the basis of IR, 2D NMR ((1)H-(1)H COSY, HSQC, HMBC and NOESY) and HRESIMS analysis. Antibacterial activity of all the compounds was evaluated using KB paper diffusion through measurement of inhibiting zone. It was found that four of all the compounds exhibited significant inhibitory activity against Gram-positive bacteria Bacillus subtilis with MIC values of 25 µg/ml (compounds 1-3) and 15 µg/ml (compound 4).

Coupling photocatalytic water oxidation with reductive transformations of organic molecules.

The utilization of readily available and non-toxic water by photocatalytic water splitting is highly attractive in green chemistry. Herein we report that light-induced oxidative half-reaction of water splitting is effectively coupled with reduction of organic compounds, which provides a light-induced avenue to use water as an electron donor to enable reductive transformations of organic substances. The present strategy allows various aryl bromides to undergo smoothly the reductive coupling with Pd/g-C3N4* as the photocatalyst, giving a pollutive reductant-free method for synthesizing biaryl skeletons. Moreover, the use of green visible-light energy endows this process with more advantages including mild conditions and good functional group tolerance. Although this method has some disadvantages such as a use of environmentally unfriendly 1,2-dioxane, an addition of Na2CO3 and so on, it can guide chemists to use water as a reducing agent to develop clean procedures for various organic reactions.

Cu2 O-Catalyzed Conversion of Benzyl Alcohols Into Aromatic Nitriles via the Complete Cleavage of the C≡N Triple Bond in the Cyanide Anion.

Nitrogen transfer from cyanide anion to an aldehyde is emerging as a promising method for the synthesis of aromatic nitriles. However, this method still suffers from a disadvantage that a use of stoichiometric Cu(II) or Cu(I) salts is required to enable the reaction. As we report herein, we overcame this drawback and developed a catalytic method for nitrogen transfer from cyanide anion to an alcohol via the complete cleavage of the C≡N triple bond using phen/Cu2 O as the catalyst. The present condition allowed a series of benzyl alcohols to be smoothly converted into aromatic nitriles in moderate to high yields. In addition, the present method could be extended to the conversion of cinnamic alcohol to 3-phenylacrylonitrile.