Inside Cover: Ir‐Catalyzed Asymmetric Hydrogenation of α‐Alkylidene β‐Lactams and Cyclobutanones (Chin. J. Chem. 7/2018)

The inside cover picture shows Chiral β‐lactams and cyclobutanones are present in numerous natural and pharmaceutical products. A direct preparation of chiral four‐membered rings via metal‐catalyzed asymmetric hydrogenation has not been described yet. In this article, we report an Ir/BiphPHOX‐catalyzed asymmetric hydrogenation of α‐alkylidene β‐lactams and cyclobutanones for the direct preparation of β‐lactams and cyclobutanones bearing an α‐substituted stereocenter. Our tropos phosphine‐oxazoline biphenyl ligand is essential for the preparation of the desired products with high enantioselectivities. More details are discussed in the article by Zhang et al. on page 612–618.

     

Back Cover: Synthesis,Nematicidal Activity,and 3D‐QSAR of Novel 1,3,4‐Oxadiazole/ Thiadiazole Thioether Derivatives (Chin. J. Chem. 10/2018)

The back cover picture shows As two important heterocyclic active groups, oxadiazole and thiadiazole are used to develop new pesticide with high efficiency and broad spectrum of biological activities. On the basis of our previous works, forty one novel 1,3,4‐oxadiazole/thiadiazole thioether derivatives were synthesized and their nematicidal activities against Tylenchulus semipenetrans were evaluated. And compound 33 was designed by using the CoMFA and CoMSIA models, which exhibited excellent nematicidal acivity in vitro. More details are discussed in the article by Song et al. on page 939‐944.

     

Back Cover: Lactonization of C(sp2)—H Bonds in Enamides with CO2 (Chin. J. Chem. 5/2018)

The back cover picture shows a novel synthesis of 1,3‐oxazin‐6‐ones from enamides with CO₂ through C—H carboxylation and one‐pot cyclization. The concept of “CO₂ = CO + O”, using CO₂ to replace toxic CO and stoichiometric oxidant, guilds the development of this chemistry as well as green and safe synthetic methods in the future. More details are discussed in the article by Yu et al. on page 430–436.

     

Cover Picture: Palladium‐Catalyzed Intermolecular Oxidative Coupling Reactions of (Z)‐Enamines with Isocyanides through Selective β‐C(sp2)‐H and/or C=C Bond Cleavage (Chin. J. Chem. 8/2018)

The cover picture shows Two efficient intermolecular oxidative coupling reactions of (Z)‐enamines with isocyanides via palladium catalysis have been developed. In these transformations, the β‐C(sp²)‐H and/or C ＝ C bond were cut off selectively by using different anionic ligands, leading to controllable chemodivergent and stereoselective construction of a wide range of (E)β‐carbamoylenamine derivatives with intramolecular hydrogen bonds. More details are discussed in the article by Jiang et al. on page 712–715.

     

Cover Picture: Visible Light Accelerated Vinyl C–H Arylation in Pd‐Catalysis: Application in the Synthesis of ortho Tetra‐substituted Vinylarene Atropisomers (Chin. J. Chem. 1/2018)

The cover picture shows a protocol of a palladium‐catalyzed arylation of vinylarenes with diaryliodonium salts with the assistance of visible light. A palladium‐vinylarene complex may be excited via the visible light irradiation, where the kinetic isotope effect (k_H/k_D) was around 1.1. However under darkness, the reaction proceeded very slowly, and the kinetic isotope was found as 3.6, indicating the C—H bond cleavage step is the rate‐determining step. This protocol avoided high reaction temperature and enabled us to access a series of ortho tetra‐substituted vinylarene atropisomers with high enantiospecificity. More details are discussed in the article by Gu et al. on page 11–14.

     

Cover Picture: Electrochemical Synthesis of (Aza)indolines via Dehydrogenative [3+2] Annulation: Application to Total Synthesis of (±)‐Hinckdentine A (Chin. J. Chem. 10/2018)

The cover picture shows an electricity powered dehydrogenative [3+2] annulation reaction of (hetero)arylamines with tethered di‐, tri, and tetra‐substituted alkenes for the preparation of indoline and azaindoline products. The electrochemical reactions proceed through H2 evolution and thus avoid the use of stoichiometric chemical oxidants. This method, which is applicable to the preparation of highly functionalized (aza)indoline scaffold, enables the total synthesis of (±)‐hinckdentine A in 12 steps. More details are discussed in the article by Xu et al. on page 909–915.

     

Back Cover: Synthesis,Structure and Biological Activities of Novel 2‐(Trifluoromethyl)‐ 6‐arylimidazo[2,1‐b][1,3,4]‐thiadiazole (bis‐)Mannich Base Derivatives Containing Substitutedpiperazine Moiety (Chin. J. Chem. 7/2018)

The back cover picture shows a convenient and practicable synthesis of novel 2‐(trifluoromethyl)‐6‐arylimidazo[2,1‐b][1,3,4]‐thiadiazole (bis‐)Mannich base derivatives containing various substitutedpiperazine motif. Based on the C‐Mannich reaction of unusual intermediate – 2‐(trifluoromethyl)‐6‐arylimidazothiadiazole, with (4‐substituted) piperazine and formaldehyde in ethanol and acetic acid, the target compounds have been achieved conveniently with satisfying yields. Meanwhile, the cover picture shows that some of the target compounds possess favourable pesticidal activities (e.g. fungicidal and insecticidal). This research will provide important information for relevant synthetic studies of imidazole‐fused‐heterocycle derivatives and their applications in agrochemical area. More details are discussed in the article by Wang et al. on page 635–638.

     

Inside Cover: Temperature‐responsive Catalyst for the Coupling Reaction of Carbon Dioxide and Propylene Oxide (Chin. J. Chem. 4/2018)

The inside cover picture shows a temperature controllable porphyrin aluminum catalyst using 5,10,15,20‐tetra(1,2,3,4,5,6,7,8‐octahydro‐1,4:5,8‐dimethanoanthracen‐9‐yl)porphyrin as ligand, which showed significantly temperature‐responsive selectivity in the coupling reaction of CO₂ and PO. Only cycloaddition reaction happened at temperature above 75 °C to produce 100% CPC, whereas copolymerization became dominant to afford PPC with selectivity over 91% at temperature below 50 °C. More details are discussed in the article by Wang et al. on page 299–305.

     

Cover Picture: Understanding Zeolites Catalyzed Methanol‐to‐Olefins Conversion from Theoretical Calculations (Chin. J. Chem. 5/2018)

The cover picture shows the complexity of the reaction mechanism of zeolites catalyzed methanol‐to‐olefins (MTO) conversion. The MTO process plays a vital role in the production of light olefins from nonpetroleum resources. Despite of the successful industrialization of the MTO process in China, the detailed reaction mechanism is not yet well understood. The theoretical studies on the MTO hydrocarbon pool mechanism by the Group of Xie are summarized in the Chemistry Author Up Close by Xie et al. on page 381–386.

     

Cover Picture: Building up 1‐D, 2‐D,and 3‐D Polyiodide Frameworks by Finely Tuning the Size of Aryls on Ar‐S‐TTF in the Charge‐Transfer (CT) Complexes of Ar‐S‐TTFs and Iodine (Chin. J. Chem. 9/2018)

The cover picture shows The arylthio‐substituted tetrathiafulvalenes (Ar‐S‐TTFs) are electron donors having three reversible states, neutral, cation radical, and dication. The charge‐transfer (CT) between Ar‐S‐TTFs and iodine (I2) occurs in solution, whereas the Ar‐S‐TTFs are partially at cation radical state. In CT complexes of Ar‐S‐TTFs with I₂, the charged states of Ar‐S‐TTFs are distinctly increased, say, the dicationic state is observed. The iodine components in CT complexes show various structures including 1‐D polymeric chain, and 2‐D and 3‐D iodine networks. More details are discussed in the article by Shao et al. on page 845–850.

     

Back Cover: Dual Stereocontrol for Enantioselective Hydrogenation of Dihydroisoquinolines Induced by Tuning the Amount of N‐Bromosuccinimide (Chin. J. Chem. 2/2018)

The back cover picture shows an efficient dual enantioselective synthesis of 1‐substituted 1,2,3,4‐tetrahydroisoquinoline, which was realized through iridium‐catalyzed hydrogenation of 1‐substituted 3,4‐dihydroisoquinolines. Only tuning the amount of N‐bromosuccinimide, this reaction promoted by (R)‐BINAP is able to furnish both enantiomers of products up to 89% ee (S) and 98% ee (R), respectively. Dual activation role of N‐bromosuccinimide is proposed to be responsible for the reversal of enantioselectivity under two hydrogenation conditions. More details are discussed in the article by Zhou et al. on page 139–142.

     

Cover Picture: Nitrogen Analogues of o‐Quinodimethane with Unexpected non‐Kekulé Diradical Character (Chin. J. Chem. 6/2018)

The cover picture shows para‐Quinodimethane (p‐QDM) and ortho‐quinodimethane (o‐QDM) are two typical examples of Kekulé‐type delocalized diradicals. The cover picture shows that the replacement of the carbinyl centers with isoelectronic aminium centers leads to the formation of isolable nitrogen analogues of o‐QDM. In contrast to o‐QDM, the nitrogen analogues exhibit unexpected non‐Kekulé diradical characters and features open‐shell singlet ground states with thermally accessible triplet states. More details are discussed in the article by wang et al. on page 487–490.

     

Inside Cover: Synthetic Strategies for Constructing Two‐Dimensional Metal‐Organic Layers (MOLs): A Tutorial Review (Chin. J. Chem. 8/2018)

The inside cover picture shows Metal‐organic layer (MOL), the two‐dimensional analog of metal‐organic framework (MOF), is a new member of two‐dimensional materials. This tutorial review summarizes current synthetic approaches for MOL preparation. More details are discussed in the article by Wang et al. on page 754–764.

     

Cover Picture: Synthesis of Subnanometer‐Sized Gold Clusters by a Simple Milling‐Mediated Solid Reduction Method (Chin. J. Chem. 4/2018)

The cover picture shows a simple milling‐mediated solid reduction method for fabricating of ultrafine gold catalysts. By solid grinding of the N‐modified SiO₂ supported Au precursors with NaBH₄, subnanometer‐sized clusters and isolated Au atoms can be facilely obtained by tuning the metal loading. This method establishes a good basis for fundamental understanding the size effect of Au in the hydrogenation of CO₂ to formate, and provides a general methodology for supported nano‐catalyst preparation. More details are discussed in the article by Huang et al. on page 329–332.

     

Cover Picture: A Three‐dimensional Non‐fullerene Small Molecule Acceptor for Solution‐processed Organic Solar Cells (Chin. J. Chem. 11/2017)

The cover picture shows a new three‐dimensional non‐fullerene small molecular acceptor for solution‐processed organic solar cells. The acceptor was named SFTTIC using spiro‐bifluorene as the core unit linking with four thieno[3,2‐b ]thiophenes and end‐capped with 2‐(3‐oxo‐2,3‐dihydro‐1H ‐inden‐1‐ylidene)malononitrile. SFTTIC has a high absorption coefficient, good thermal stability and appropriate energy levels and the optimized power conversion efficiency (PCE) of 5.66% was achieved for the devices with PBDB‐T as donor material. These results indicate that the 3D non‐fullerene small molecule is potential for achieving high photovoltaic performance. More details are discussed in the article by Chen et al. on page 1687–1692.

     

Cover Picture: Construction of Crown Ether‐Stoppering [3]Rotaxanes Based on N‐Hetero Crown Ether Host (Chin. J. Chem. 7/2017)

The cover picture shows shows the construction of crown etherstoppering [3]rotaxanes based on N ‐hetero crown ether host. Usually, crown ethers play the role of host macrocycles to combine with the guest molecules in the construction of rotaxanes. Based on the fact that crown ethers have large dimension, two [3]rotaxanes containing four crown ether units were designed and synthesized, of which, two N ‐hetero crown ether components were employed as the macrocyclic hosts to assemble the mechanically interlocked framework by using a template‐directed clipping reaction while bis (metaphenylene‐26‐crown‐8) located on two sides of template diammonium acting as the stoppering groups of [3]rotaxanes. More details are discussed in the article by Yin et al. on page 1050–1056.

     

Cover Picture: Nickel‐Catalyzed Cross‐Electrophile Coupling of Aryl Bromides with Pyrimidin‐2‐yl Tosylates (Chin. J. Chem. 9/2017)

The cover picture shows a new protocol for the NiCl₂ ‐catalyzed cross‐electrophile coupling of aryl bromides with pyrimidin‐2‐yl tosylates to give the corresponding C2 ‐arylation pyrimidine derivatives. This study provides an improvement over previous methods by using pyrimidin‐2‐yl tosylates instead of halides as coupling partners that are stable and easily available. More details are discussed in the article by Wang et al. on page 1366–1370.

     

Back Cover: Internally Reuse Waste: Catalytic Asymmetric One‐Pot Strecker Reaction of Fluoroalkyl Ketones,Anilines and TMSCN by Sequential Catalysis (Chin. J. Chem. 4/2018)

A highly enantioselective one‐pot Strecker reaction of α‐fluoroalkyl α‐aryl ketones, anilines, and TMSCN is disclosed, which simultane‐ously reuses water byproduct and catalyst from the ketimine formation step as a promoter and an additive to improve the reactivity and enantioselectivity of the subsequent Strecker reaction, respectively. The picture shows that the chiral bifunctional tertiary amine mediated asymmetric Strecker reaction is irrigated by the water generated in the p‐TsOH catalyzed ketimine formation, and fertilized by the remaining acid catalyst. More details are discussed in the article by Zhou et al. on page 321–328.

     

Back Cover: Asymmetric Synthesis of the Ring A Substructure of Genkwadane A (Chin. J. Chem. 9/2018)

The back cover picture shows Genkwadane A was isolated from the flower buds of Daphne genkwa which shows bioactivity against HeLa, HepG2, HT‐1080, MCF‐7, A549, U‐937, K562 and HL60 cell lines. It is the first time that a daphnane diterpenoid bearing a 1,10‐double bond was isolated. In this paper, B. Liu and co‐workers report asymmetric synthesis of the ring A substructure of genkwadane A in 10 steps from D‐tartrate derivative. More details are discussed in the article by Liu et al. on page 831–836.