Copper/Silver‐Mediated Direct ortho‐Ethynylation of Unactivated (Hetero)aryl CH Bonds with Terminal Alkyne

A copper/silver‐mediated oxidative ortho‐ethynylation of unactivated aryl C?H bonds with terminal alkyne has been developed. The reaction uses the removable PIP directing group and features broad substrate scope, high functional‐group tolerance, and compatibility with a wide range of heterocycles, providing an efficient synthesis of aryl alkynes. This procedure highlights the potential of copper catalysts to promote unique, synthetically enabling C?H functionalization reactions that lie outside of the current scope of precious metal catalysis.     

Synthesis of a Specified,Silica Molecular Sieve by Using Computationally Predicted Organic Structure‐Directing Agents

Crystalline molecular sieves are used in numerous applications, where the properties exploited for each technology are the direct consequence of structural features. New materials are typically discovered by trial and error, and in many cases, organic structure‐directing agents (OSDAs) are used to direct their formation. Here, we report the first successful synthesis of a specified molecular sieve through the use of an OSDA that was predicted from a recently developed computational method that constructs chemically synthesizable OSDAs. Pentamethylimidazolium is computationally predicted to have the largest stabilization energy in the STW framework, and is experimentally shown to strongly direct the synthesis of pure‐silica STW. Other OSDAs with lower stabilization energies did not form STW. The general method demonstrated here to create STW may lead to new, simpler OSDAs for existing frameworks and provide a way to predict OSDAs for desired, theoretical frameworks.     

Ligand‐Enabled β‐Methylene C(sp3)−H Arylation of Masked Aliphatic Alcohols

Despite recent advances, reactivity and site‐selectivity remain significant obstacles for the practical application of C(sp³)?H bond functionalization methods. Here, we describe a system that combines a salicylic‐aldehyde‐derived L,X‐type directing group with an electron‐deficient 2‐pyridone ligand to enable the β‐methylene C(sp³)?H arylation of aliphatic alcohols, which has not been possible previously. Notably, this protocol is compatible with heterocycles embedded in both alcohol substrates and aryl coupling partners. A site‐ and stereo‐specific annulation of dihydrocholesterol and the synthesis of a key intermediate of englitazone illustrate the practicality of this method.     

A Simple and Versatile Amide Directing Group for C−H Functionalizations

Achieving selective C?H activation at a single and strategic site in the presence of multiple C?H bonds can provide a powerful and generally useful retrosynthetic disconnection. In this context, a directing group serves as a compass to guide the transition metal to C?H bonds by using distance and geometry as powerful recognition parameters to distinguish between proximal and distal C?H bonds. However, the installation and removal of directing groups is a practical drawback. To improve the utility of this approach, one can seek solutions in three directions: 1) Simplifying the directing group, 2) using common functional groups or protecting groups as directing groups, and 3) attaching the directing group to substrates via a transient covalent bond to render the directing group catalytic. This Review describes the rational development of an extremely simple and yet broadly applicable directing group for Pd^II, Rh^III, and Ru^II catalysts, namely the N‐methoxy amide (CONHOMe) moiety. Through collective efforts in the community, a wide range of C?H activation transformations using this type of simple directing group have been developed.     

Nano palladium catalyzed C(sp3)-H bonds arylation by a transient directing strategy

Reported herein is the first example of heterogeneous palladium catalyzed C(sp³)-H bonds arylation by a transient-ligand-directed strategy.Using supported palladium(metallic state) na nopariticles as catalyst,a wide range of aryl iodides undergo the coupling with various o-methylbenzaldehyde derivatives to assemble a library of highly selective and functionalized o-benzylbenzaldehydes.The stability of the catalyst was easily recovered four runs without significant loss of activity.The XPS analysis of the catalyst before and after reaction indicated that the reaction might be carried out by a catalytic cycle starting with Pd~0.     

Rhodium-Catalyzed C−H Methylation and Alkylation Reactions by Carbene-Transfer Reactions

In this combined computational and experimental study, the C−H functionalization of 2-phenyl pyridine with diazoalkanes was investigated. Initial evaluation by computational methods allowed the evaluation of different metal catalysts and diazoalkanes and their compatibility in this C−H functionalization reaction. With these findings, suitable reaction conditions for the C−H methylation reactions were quickly identified by using highly reactive TMS diazomethane and C−H alkylation reactions with donor/acceptor diazoalkanes, which is applied to a broad scope on alkylation reactions of 2-aryl pyridines with TMS diazomethane and donor/acceptor diazoalkane (51 examples, up to 98 % yield).     

Cascade reaction for the synthesis of polycyclic aromatic hydrocarbons via transient directing group strategy

A Pd(II)-catalyzed cascade synthesis of diverse polycyclic aromatic hydrocarbons via transient directing group strategy has been developed, involving the consecutive arylation, cyclization and aromatization. The efficiency and practicality were demonstrated by wide substrate range, concise synthetic pathway and mild reaction conditions. The subsequent transformations of the benz[a]anthracene core accessed natural bioactive PAH molecules.     

新型抗HIV-1重组导向制剂SL41在毕赤酵母中的表达及活性实验

以酵母分泌型表达载体pPIC9k为基础, 通过一段柔性连接肽Linker构建含有人源化抗HIV-1 gp41单链抗体(ScFv41)和免疫诱导因子葡萄球菌肠毒素A(staphylococcal enterotoxin A, SEA)的融合表达质粒pPIC9k-SL41, 线性化后, 采用电转化法整合入巴斯德菌毕赤酵母GS115中, 经His+MutS表型鉴定、PCR分析以及G418筛选获得高拷贝重组转化子. 摇瓶培养、甲醇诱导表达、SDS-PAGE和Western Blot分析结果表明, 目的蛋白得到良好表达, 表达量最高可达到47.9 mg/L. 目的蛋白经初步纯化后, 用于制备的HIV-1感染靶细胞复制模型进行抗体亲和力测定、细胞结合活性测定和细胞杀伤活性研究, 结果显示, 目的蛋白能够很好地与靶细胞模型中的HIV-1外膜蛋白gp160发生结合反应, 并可介导特异的CTL反应, 对靶细胞具有明显的杀伤活性, 表明获得了具有生物活性的抗HIV-1重组导向制剂.