抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Catalytic dehydrogenative cross-coupling: forming carbon-carbon bonds by oxidizing two carbon-hydrogen bonds

3.7. Palladium Nanoparticles as Catalysts 888 3.8. Other Transition-Metal Complexes 888 3.9. Transition-Metal-Free Reactions 889 4. Applications 889 4.1. Alkynylation of Arenes 889 4.2. Alkynylation of Heterocycles 891 4.3. Synthesis of Enynes and Enediynes 894 4.4. Synthesis of Ynones 896 4.5. Synthesis of Carbocyclic Systems 897 4.6. Synthesis of Heterocyclic Systems 898 4.7. Synthesis of Natural Products 903 4.8. Synthesis of Electronic and Electrooptical Molecules 906

https://www.chem.ccu.edu.tw/~joyce/referance/ericyang/Chem.%20Rev/Chem.%20Rev.%202007,%20107,%20874-922.pdf

The Sonogashira Reaction: A Booming Methodology in Synthetic Organic Chemistry†

The direct functionalization of C-H bonds in organic compounds has recently emerged as a powerful and ideal method for the formation of carbon-carbon and carbon-heteroatom bonds. This Review provides an overview of C-H bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.

C-H bond functionalization: emerging synthetic tools for natural products and pharmaceuticals

Nickel-Catalyzed Cross-Couplings Involving Carbon-Oxygen Bonds Brad M. Rosen, Kyle W. Quasdorf, Daniella A. Wilson, Na Zhang, Ana-Maria Resmerita, Neil K. Garg,* and Virgil Percec* Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States

/pdf/nickel-catalyzed-cross-couplings-involving-carbon-oxygen-1zs88el3fl.pdf

Nickel-Catalyzed Cross-Couplings Involving Carbon-Oxygen Bonds

Amides are common functional groups that have been studied for more than a century. They are the key building blocks of proteins and are present in a broad range of other natural and synthetic compounds. Amides are known to be poor electrophiles, which is typically attributed to the resonance stability of the amide bond. Although amides can readily be cleaved by enzymes such as proteases, it is difficult to selectively break the carbon-nitrogen bond of an amide using synthetic chemistry. Here we demonstrate that amide carbon-nitrogen bonds can be activated and cleaved using nickel catalysts. We use this methodology to convert amides to esters, which is a challenging and underdeveloped transformation. The reaction methodology proceeds under exceptionally mild reaction conditions, and avoids the use of a large excess of an alcohol nucleophile. Density functional theory calculations provide insight into the thermodynamics and catalytic cycle of the amide-to-ester transformation. Our results provide a way to harness amide functional groups as synthetic building blocks and are expected to lead to the further use of amides in the construction of carbon-heteroatom or carbon-carbon bonds using non-precious-metal catalysis.

/pdf/conversion-of-amides-to-esters-by-the-nickel-catalysed-20ajnazqro.pdf

Conversion of amides to esters by the nickel-catalysed activation of amide C-N bonds

Amides have been widely studied for decades, but their synthetic utility has remained limited in reactions that proceed with rupture of the amide C–N bond. Using Ni catalysis, we have found that amides can now be strategically employed in several important transformations: esterification, transamidation, Suzuki–Miyaura couplings, and Negishi couplings. These methodologies provide exciting new tools to build C–heteroatom and C–C bonds using an unconventional reactant (i.e., the amide), which is ideally suited for use in multi-step synthesis. It is expected that the area of amide C–N bond activation using nonprecious metals will continue to flourish and, in turn, will promote the growing use of amides as synthons in organic synthesis.

Breaking Amides using Nickel Catalysis

The first cross-coupling of acylated phenol derivatives has been achieved. In the presence of an air-stable Ni(II) complex, readily accessible aryl pivalates participate in the Suzuki−Miyaura coupling with arylboronic acids. The process is tolerant of considerable variation in each of the cross-coupling components. In addition, a one-pot acylation/cross-coupling sequence has been developed. The potential to utilize an aryl pivalate as a directing group has also been demonstrated, along with the ability to sequentially cross-couple an aryl bromide followed by an aryl pivalate, using palladium and nickel catalysis, respectively.

Cross-coupling reactions of aryl pivalates with boronic acids.

The Suzuki-Miyaura coupling has become one of the most important and prevalent methods for the construction of C-C bonds. Although palladium catalysis has historically dominated the field, the use of nickel catalysis has become increasingly widespread because of its unique ability to cleave carbon-heteroatom bonds that are unreactive towards other transition metals. We report the first nickel-catalysed Suzuki-Miyaura coupling of amides, which proceeds by an uncommon cleavage of the amide C-N bond after N-tert-butoxycarbonyl activation. The methodology is mild, functional-group tolerant and can be strategically employed in sequential transition-metal-catalysed cross-coupling sequences to unite heterocyclic fragments. These studies demonstrate that amides, despite classically considered inert substrates, can be harnessed as synthons for use in reactions that form C-C bonds through cleavage of the C-N bond using non-precious metal catalysis.

Neil K. Garg

Papers

Nickel-Catalyzed Cross-Couplings Involving Carbon-Oxygen Bonds

Conversion of amides to esters by the nickel-catalysed activation of amide C-N bonds

Breaking Amides using Nickel Catalysis

Cross-coupling reactions of aryl pivalates with boronic acids.

Nickel-catalysed Suzuki–Miyaura coupling of amides