From Reactivity and Regioselectivity to Stereoselectivity: An Odyssey of Designing PIP Amine and Related Directing Groups for C—H Activation

Improving the reactivity and selectivity is a long pursuing goal in C—H functionalization reactions. In line with this goal, a well‐designed bidentate 2‐(pyridine‐yl)isopropyl amine (PIP amine) directing group was developed by our group to achieve the activation of unbiased methylene C(sp³)–H activation, which also found its broad applications in C—H activation reactions catalyzed by base metals, such as Cu, Ni, Co and Fe, to form various C—C and C—X bonds. Moreover, PIP amine has also been applied in the strategic step toward the total synthesis of aeruginosin marine natural products. Its highly tunable structure has triggered the design of a series of chiral auxiliaries for diastereoselective C—H activation. More recently, Pd(II)‐catalyzed enantioselective functionalization of unbiased methylene C(sp³)–H bonds enabled by the cooperative effects between PIP amine and chiral ligands with axially chiral binaphthyl scaffold has also been realized. In this account, we briefly summaries the journey of developing PIP amine for C—H activation, from controlling the reactivity and regioselectivity to stereoselectivity.     

Inside Cover: Biomimetic Chiral Pyridoxal and Pyridoxamine Catalysts (Chin. J. Chem. 2/2019)

The inside cover picture shows the development of chiral pyridoxal and pyridoxamine catalysts by mimicking vitamin B₆‐dependent enzymes. These chiral pyridoxals and pyridoxamines displayed extraordinary catalytic performances in asymmetric biomimetic transamination and Mannich reaction, to give various chiral α‐amino acids and α,β‐diamino acid esters in good yields with excellent diastero‐ and/or enantioselectivities. The research has provided some useful information for further applications of the catalytic power of vitamin B6 in the area of asymmetric cayalysis. More details are discussed in the article by Zhao et al. on page 103–112.

     

Inside Cover: Construction of Highly Emissive Pt(II) Metallacycles upon Irradiation (Chin. J. Chem. 4/2019)

The inside cover picture shows  in situ construction of highly emissive Pt(II) metallacycles upon irradiation. The self‐assembled diarylethene‐containing metallacycles can realize supramolecular transform from the open‐ring isomers to their closed‐ring ones under UV irradiation. Moreover, the closed‐ring isomers featured a relatively high fluorescence quantum yield. This property of “turn‐on” fluorescence switching provides a new method to construct highly emissive supramolecular fluorescent materials by light stimulus. More details are discussed in the article by Yang et al. on page 323–329.

     

Inside Back Cover: Photochemical and Electrochemical Carbon Dioxide Utilization with Organic Compounds (Chin. J. Chem. 7/2018)

Inside Back Cover picture shows The carps trying hard to make a successful jump over the Dragon Gate will change into fish‐dragons, which is a legend handed down in China over generations. The back cover picture shows photochemical and electrochemical CO₂ transformations with organic compounds through the utilization of solar energy or electric energy, producing a series of valuable products, including carboxylic acids and hetero‐cyclic compounds. The combined utilization of both clean energy and CO₂ has attracted increasing attention in sustainable development of renewable energy and green chemistry. Recent advances are summarized by He et al. on page 644–659.

     

Cover Picture: Benzene Triimides: Facile Synthesis and Self‐Assembly Study (Chin. J. Chem. 7/2019)

The cover picture shows an efficient one‐pot condensation of maleimide derivatives in the presence of acetic acid and water to afford a series of benzene triimides (BTIs). The structure, physicochemical properties and electrochemistry behavior of BTIs were systematically investigated. Owing to the planar structure and unique electron‐deficient nature, BTIs can self‐assemble into different motifs. More details are discussed by Wang et al. on page 684–688.

     

Back Cover: Electrochemical Radical Borylation of Aryl Iodides (Chin. J. Chem. 4/2019)

The back cover picture shows an electrochemical strategy for the borylation of aryl iodides via a radical pathway using current as a driving force. This method features mild reaction conditions, good functional groups tolerance, and prompt reaction time. EPR, CV and DPV experiments verified the formation of aryl radicals in this electrochemical borylation reaction, and the current plays an important role in the generation of radical intermediate. More details are discussed in the article by Mo et al. on page 347–351.

     

Inside Cover: Palladium‐Catalyzed Asymmetric Dihydroxylation of 1,3‐Dienes with Catechols (Chin. J. Chem. 3/2019)

The inside cover picture shows a palladium‐catalyzed asymmetric dihydroxylation of 1,3‐dienes with catechols utilizing chiral pyridinebis(oxazoline) ligand. The reaction is proposed to proceed via a cascade Wacker‐type hydroxypalladation/asymmetric allylation process. This methodology provides a direct and straightforward synthesis to prepare chiral 2‐substituted 1,4‐benzodioxane motifs in moderate to good yield and enantioselectivity from readily available starting materials. More details are discussed in the article by Gong et al. on page 226–232.

     

Cover Picture: Electrochemical Oxidative Csp3—H/S—H Cross‐Coupling with Hydrogen Evolution for Synthesis of Tetrasubstituted Olefins (Chin. J. Chem. 6/2019)

The inside cover picture shows an electrochemical oxidative Csp³‐H/S‐H activation with hydrogen evolution for the synthesis of tetrasubstituted olefins. This method features very high atom economy, besides hydrogen gas, under the base‐free, transition met‐al‐free, and oxidants‐free conditions, no other by‐products were generated. More details are discussed in the article by Lei et al. on page 547–551.

     

Inside Cover: Structural Designs for Accommodating Volume Expansion in Sodium Ion Batteries (Chin. J. Chem. 9/2018)

The inside cover picture shows that four effective routes are applied to the anode material to help it keep fit, which is out of shape due to the intake of sodium ions. As a result, the sodium ion batteries (SIBs) with this anode exhibit high electrochemical performances, so that they tend to meet the demand for large‐scale energy storage devices. In this review, four strategies based on structural designs are summarized in order to accommodate volume changes of anode materials in SIBs, including nanoarchitecture configuration, buffer matrix protection, cavity volume reservation, and interlayer spacing regulation. More details are discussed in the review by Fu et al. on page 866–874.

     

Inside Back Cover: Allosteric Modulation of Human Serum Albumin Induced by Peptide Ligand (Chin. J. Chem. 8/2017)

The inside back cover picture shows the allosteric modulation of human serum albumin (HSA) induced by the Peptide SA06 ligand. Peptide SA06 is a reported peptide ligand comprising 20 amino acids, and is known to non‐covalently bind with HSA to extend the lifetime and improve the pharmacokinetic performance of drug molecules. The structural evidence on the allosteric interaction between peptide ligand and HSA, and the structure‐affinity relations of the binding mechanism have been revealed in this work, which can also shed light on optimization of therapeutic properties in the affinity‐controlled delivery systems. More details are discussed in the article by Wang et al. on page 1270–1277.

     

Inside Cover: A Computational Study on Iridium‐Catalyzed Production of Acetic Acid from Ethanol and Water Solution (Chin. J. Chem. 9/2019)

The inside cover picture shows the hydrogen transfer process of the production of acetic acid from ethanol and water mixture catalyzed by iridium catalyst owning bpyO ligand. A DFT mechanistic study indicates that the cooperation of the iridium center and bpyO ligand plays an important role in the catalytic activity, and that the hydrogen release process from the iridium center is the rate‐determining step. More details are discussed in the article by Lei et al. on page 883–886.