Ni／SiO2催化剂上间二硝基苯液相加氢制间苯二胺

 将等体积浸渍法制备的Ni／SiO2催化剂应用于间二硝基苯液相加氢制间苯二胺反应中，通过BET，XRD，TEM，TPR，H2－TPD和活性评价等方法对催化剂的物化性质及催化性能进行了研究，考察了镍含量对催化剂活性的影响．结果表明，Ni／SiO2催化剂不仅具有很高的催化活性，而且对间苯二胺表现出很高的选择性；催化剂的活性随着镍含量的不同而有所变化．当w（Ni）＜20％时，随着镍负载量的增加，催化剂的活性逐渐升高，而当w（Ni）≥20％时，催化剂的活性和选择性基本趋于稳定．影响催化剂活性及选择性的主要因素是催化剂的活性比表面积．     

An easy and stereoselective synthesis of N-Boc-dolaproine via the Baylis-Hillman reaction

In this communication we report a stereoselective total synthesis of N-Boc-dolaproine (Dap), an amino acid residue of the antineoplastic pentapeptide Dolastatin 10. Our strategy is based on a Baylis-Hillman reaction between N-Boc-prolinal and methyl acrylate, followed by a diastereoselective double bond hydrogenation and hydrolysis of the ester function.     

Solution Structure and Behavior of Benzophenone-based Achiral Bisphosphine Ligands in Noyori-Type Ru（Ⅱ）-Catalysts

We herein report on solution structural studies of Ru^Ⅱ catalysts （3a, 9） composed of achiral bisphosphine ligands （4, 8） and the enantiopure 1,2-diphenylethylenediamine （DPEN）. Complete chiral induction from enantiopure （R,R）-DPEN to achiral bisphosphine ligand 3a was observed in solution, with the complex adopting a single, stable and non-fluxional （even at 70 ℃） configuration. The coordination of the C=O moiety in 4 to the cationic Run center is considered to be of key importance in providing the higher thermodynamic and kinetic rotation barrier for the flexible bisphosphine ligand in the complex. The obtained enantioselectivity （91% enantiomeric excess） and sense of chiral induction in the hydrogenation of acetophenone were found to be solely dependent on the chirality of the 1,2-diamine. Consistent with the hydrogenation product, the （R,R）-DPEN induces a M-conformation （fight-handed） chirality for flexible phosphine ligand 4 in the complex, resulting in a 2,2-configuration about the Ru^Ⅱ center.     

Synthesis of chiral γ-lactones via a RuPHOX-Ru catalyzed asymmetric hydrogenation of aroylacrylic acids

An asymmetric hydrogenation of aroylacrylic acids catalyzed by RuPHOX-Ru catalyst has been developed, affording the corresponding chiral γ-lactones in high yields and with up to 93% ee. The methodology has the advantage of utilizing easily accessible substrates and has therefore expand the scope of the resulting chiral γ-lactones. Furthermore, high catalytic efficiency was achieved in that the reduction of both the CC and CO double bonds was achieved in one step. The current work provides an alternative and convenient pathway for the synthesis of a wide range of chiral γ-lactones.     

Novel Synthesis of Mafenide and Other Amino Sulfonamides by Electrochemical Reduction of Cyano Sulfonamides

Both aliphatic and aromatic amino sulfonamides such as mafenide ( 1a ) were synthesized in good yields (80–86%) by direct electrochemical hydrogenation of the corresponding nitriles in an undivided cell containing a Ni cathode, a Pt anode, and Raney Ni as catalyst (Table 1). The reaction can be performed without external supply of pressurized gas by in situ generation of H₂. Slightly elevated temperatures (45°) and low current densities (10 mA/cm²) are favorable conditions for this type of electrochemical nitrile hydrogenation. Our synthetic protocol does not require high‐pressure equipment or chemical hazards, is environmentally very friendly, and more economical than traditional methods. The concentration of adsorbed H^. radicals on the catalyst surface can be easily controlled by adjusting the electric potential, which may lead to improved product selectivity and, at the same time, reduces the risk of explosion and fire.     

Facile catalyzed acylation of alcohols, phenols, amines and thiols based on ZrOCl2·8H2O and acetyl chloride in solution and in solvent-free conditions

Acylation of heteroatoms (O, N and S) with acetyl chloride based on the use of a catalytic amount of the moisture stable, inexpensive ZrOCl₂·8H₂O, proceeds efficiently producing the corresponding acylated products in excellent yields.     

Selective Electrocatalytic Hydrogenation of trans-2-Allyl-6-methyl(allyl, phenyl)-1,2,3,6-tetrahydropyridines on the Nickel and Copper Cathodes

It is shown that the electrocatalytic hydrogenation (ECH) of trans-2-allyl-6-R-1,2,3,6-tetrahydropyridines (R = Me, All, Ph) on a nickel cathode (Ni_disp/Ni) in 40-% aqueous DMF in the presence of excess AcOH yields products of total hydrogenation of all double bonds—relevant trans-2-propyl-6-R₁-piperidines (R₁ = Me, Pr, Ph). Selective hydrogenation of terminal double bonds of allyl substituents in piperideines under study with the retention of the intracycle double bond may be realized on a copper cathode (Cu_ann), provided the stoichiometric ratio between AcOH and the initial substance is observed exactly. In either case, at points of maximum selectivity of ECH processes, the ratio c _AcOH/c _ini = n+ 1, where nis the number of hydrogenated bonds. The difference in the ECH mechanisms on the Cu_ann and Ni_disp/Ni cathodes is discussed. The results of hydrogenation of the trans-2-allyl-6-R-1,2,3,6-tetrahydropyridines at the Cu_ann and Ni_disp/Ni cathodes confirm the general character of regularities discovered earlier during ECH of citral.     

树状催化剂在不对称氢转移反应中的回收循环使用研究

以(1S,2R)-降麻黄碱为核心的第三代手性树状催化剂在对苯乙酮的不对称氢转移反应中可以方便的回收并循环使用. 该树状催化剂可以一共使用3次而保持对映选择性基本不变.     

铜基催化剂的制备方法对草酸二乙酯加氢反应的影响

草酸二乙酯加氢性成乙二醇的反应过程中，所用的铜基催化剂是由Ｃｕ（ＮＯ３）２与硅溶胶凝法制得的。本文考察了该催化剂的ＴＰＲ特性，结果表明，随着催化剂中Ｃｕ／ＳｉＯ２值的增大，其ＴＰＲ主峰ＴＭ峰温有所升高，这意味着催化剂的还原温度随Ｃｕ／ＳｉＯ２值的增大而提高。用ＸＲＤ和ＸＰＳ等手段对该催化剂还原后铜的含量及价态进行了考察，表明用胶凝法制备的铜基催化剂，还原后存在Ｃｕ＾ｏ和Ｃｕ＾＋两种价态。结合活性评