We herein present a facile and column-free synthetic route toward structurally unique oxa-spirocyclic diphenol, termed as O-SPINOL. Features of the synthesis include construction all-carbon quaternary center at an early stage, key double intramolecular SNAr step to introduce spirocycles feasibility operating on >100 g scale. Both enantiomers O-SPINOL can be easily accessed through optical resolution with l-proline by control solvent. The chiral tridentate ligand O-SpiroPAP derived from has...

Asymmetric hydrogenation of α,β-unsaturated acids catalyzed by noble metals has been well established, whereas, the asymmetric with earth-abundant-metal was rarely reported. Here, we describe a cobalt-catalyzed carboxylic acids. By using chiral cobalt catalyst bearing electron-donating diphosphine ligand, high activity (up to 1860 TON) and excellent enantioselectivity >99% ee) are observed. Furthermore, is successfully applied broad spectrum acids, such as various α-aryl α-alkyl cinnamic...

Abstract Chiral carboxylic acids are important compounds because of their prevalence in pharmaceuticals, natural products and agrochemicals. Asymmetric hydrogenation α,β‐unsaturated has been widely recognized as one the most efficient synthetic approaches to afford such compounds. Although related asymmetric di‐ trisubstituted unsaturated with noble metals is well established, challenging tetrasubstituted rarely reported. We demonstrate enantioselective cyclic acyclic via cobalt(II)...

Abstract Developing catalysts with both useful enantioselectivities and million turnover numbers (TONs) for asymmetric hydrogenation of ketones is attractive industrial production high-value bioactive chiral entities but remains a challenging. Herein , we report an ultra-efficient anionic Ir-catalyst integrated the concept multidentate ligation ketones. Biocatalysis-like efficacy up to 99% ee (enantiomeric excess), 13,425,000 TON (turnover number) 224 s −1 TOF frequency) were documented...

Abstract Owing to their distinctive 1,3‐dipolar structure, the catalytic asymmetric hydrogenation of nitrones hydroxylamines has been a formidable and longstanding challenge, characterized by intricate enantiocontrol susceptibility N−O bond cleavage. In this study, transfer were accomplished with tethered TsDPEN‐derived cyclopentadienyl rhodium(III) catalyst (TsDPEN: p ‐toluenesulfonyl‐1,2‐diphenylethylene‐1,2‐diamine), reaction proceeds via novel 7‐membered cyclic transition state,...

The natural product paeonol is a rich and sustainable bioresource, its derivatives have various unique biological efficacy. As well known, Schiff bases are class of organic compounds with wide range activities, including anti-fungal, insecticidal, anti-viral, nematicidal.

A catalytic protocol for the enantio- and diastereoselective reduction of α-substituted-β-keto carbonitriles is described. The reaction involves a DKR-ATH process with simultaneous construction β-hydroxy carbonitrile scaffolds two contiguous stereogenic centers. wide range were obtained in high yields (94%-98%) excellent diastereoselectivities (up to >99% ee, up >99:1 dr). origin diastereoselectivity was also rationalized by DFT calculations. Furthermore, this methodology offers rapid access...

The development of highly active and enantioselective ligands catalysts for the asymmetric hydrogenation ketone has been goal synthetic chemists more than fifty years. Herein, a series ferrocene-based tetradentate were developed applied in Ir-catalysed ketone. hydrolytic ring-opening oxazoline moiety ligand f-amphox leads to accidental discovery efficient f-phamidol which showed extraordinarily high reactivity enantioselectivity (up 99% yield, up >99% ee 1,000,000 TON). In addition, two...

The realm of application organometallic catalysis to organic synthesis has witnessed a transformative shift in recent years, owing much the evolution ate complexes from mere reagents versatile catalysts. Ate complexes, formed through coordination neutral Lewis acid with an anionic base, have emerged as pivotal intermediates that not only facilitate transformations but also serve efficient catalysts wide range chemical reactions. This review presents fascinating journey highlighting their...

Abstract A novel Ru 0 ‐ and Rh I ‐catalyzed noncarbonylative carbonylative cycloisomerization of readily available 3‐alkynyl imine derivatives has been developed to provide 3,4‐fused or nonfused pyrrole efficiently in moderate excellent yields. The key steps involve the formation a ruthenium carbenoid intermediate rhodacycle intermediate, respectively. In these reactions, CO can serve as ligand reagent.

Abstract A novel asymmetric [4+2] annulation of vinyl ketones with oxindole‐derived α,β‐unsaturated imines has been developed in the presence a multifunctional thiourea‐phosphine catalyst derived from natural amino acid, providing first phosphine‐catalyzed enantioselective synthesis 2′,3′‐dihydro‐1′ H ‐spiro[indoline‐3,4′‐pyridin]‐2‐ones good yields excellent stereoselectivities under mild conditions. magnified image

Construction of C-N bond continues to be one part the most significant goals in organic chemistry because universal applications amines pharmaceuticals, materials and agrochemicals. However, E2 elimination through classic S

Abstract Chiral succinimide moieties are ubiquitous in biologically active natural products and pharmaceuticals. Until today, despite the great interest, little success has been made for stereodivergent synthesis of chiral succinimides. Here, we report a general efficient method accessing 3,4-disubstituted succinimides through dynamic kinetic resolution strategy based on asymmetric transfer hydrogenation. The Rh catalyst system exhibit high activities, enantioselectivities,...

A gold(i)-catalyzed cycloisomerization of easily available 1,5-enynes containing a cyclopropane ring has been developed, efficiently providing cyclobutane-fused 1,4-cyclohexadiene, tricyclic cyclobutene, biscyclopropane and 1,3-cyclohexadiene derivatives in moderate to excellent yields. When the phenyl group was not ortho substituted, 1,4-cyclohexadienes could be produced. With an substituent, three different products selectively synthesized by control temperature used gold(i) catalyst. The...

Abstract A novel phosphine‐catalyzed [4+1] annulation of maleimides with 4,4‐dicyano‐2‐methylenebut‐3‐enoates has been developed to afford spirocyclic products, and the serves as C 1 synthons. Moreover, a formal [3+2] between maleic anhydride also achieved, behaved 3 synthon in reaction, thus efficiently affording functionalized cyclopentenones. stable phosphinium‐containing zwitterionic compound is key reactive intermediate both annulations was successfully isolated. Plausible mechanisms...

Fusarium head blight, also called scab, is caused by graminearum and one of the most important destructive diseases wheat. The frequency carbendazim resistance in 1,132 isolates F. recovered from fields different regions Henan Province 2016, 2017, 2018 was determined. A total 31 resistant to were detected, including 30 moderately highly isolate. 2.7%. range effective concentration (EC50) values 1,101 sensitive 0.08 0.98 μg ml-1 2.73 13.28 ml-1, respectively. mean ± SD EC50 value 0.55 0.13...

Open AccessCCS ChemistryCOMMUNICATION1 Dec 2020Highly Enantioselective Hydrogenation of tetra- and tri-Substituted α,β-Unsaturated Carboxylic Acids with oxa-Spiro Diphosphine Ligands Gen-Qiang Chen#, Jia-Ming Huang#, Bi-Jin Lin, Chuan Shi, Ling-Yu Zhao, Bao-De Ma, Xiao-Bing Ding, Qin Yin Xumu Zhang Chen# *Corresponding authors: E-mail Address: [email protected] Department Chemistry, Guangdong Provincial Key Laboratory Catalysis, Southern University Science Technology, Shenzhen 518000 Academy...

Due to their low reactivity, difficult enantiocontrol, and proneness N–O bond cleavage, the catalytic asymmetric hydrogenation of oximes hydroxylamines has remained a significant challenge. Herein, Lewis Brønsted acid cooperation strategy was established for oximes, providing corresponding with up 95% yield 96% ee. Addition crucial obtain high conversion enantioselectivity. Mechanistic investigations indicates that thiourea fragment ligand, (In(OTf)3 or Zn(OAc)2), as well (l-CSA) played...

Abstract BACKGROUND The emergence and increasing intensification of insect pest resistance greatly shortens the service life commercial insecticides. Hence, continuous development novel insecticides is extremely necessary. Discovering new insecticide molecules based on natural products with insecticidal activity has been a popular technique made outstanding contributions in this field. RESULTS A series betulin‐cinnamic acid‐related hybrid compounds was prepared by molecular hybridization...

ABSTRACT Raspberry ketone is an aromatic phenolic natural product with a variety of bioactivities. To discover novel fungicide molecules based on raspberry ketone, total 25 ester derivatives were synthesized, and their chemical structures well characterized. Among them, most compounds have not been reported except for 3a 3n . Compound 3f exhibited the significant antifungal activity against Valsa mali EC 50 16.430 µM, indicating that its was 234.6 folds more potent than (EC : 3854.401 µM)....