- Asymmetric Synthesis of 1,2-Dihydronaphthalene-1-ols via Copper-Catalyzed Intramolecular Reductive Cyclization
-
We describe a copper-catalyzed intramolecular reductive cyclization of easily accessible benz-tethered 1,3-dienes containing a ketone moiety. This process provided biologically active 1,2-dihydronaphthalene-1-ol derivatives in good yields with excellent enantio- and diastereoselectivity. Mechanistic investigations using density functional theory revealed that (Z)- and (E)-allylcopper intermediates formed in situ from the diene and copper catalyst undergo isomerization and selective intramolecular allylation of the (E)-allylcopper form of the major product through a six-membered boatlike transition state. The resulting products were further transformed to fully saturated naphthalene-1-ols by reactions of the olefin moiety.
- Acharyya, Ranjan Kumar,Kim, Soyoung,Park, Yeji,Han, Jung Tae,Yun, Jaesook
-
p. 7897 - 7902
(2020/11/02)
-
- Chiral electron-rich PNP ligand with a phospholane motif: Structural features and application in asymmetric hydrogenation
-
Despite the remarkable reactivity that was achieved by a series of transition-metal catalysts with a PNP type ligand, the electron-rich chiral PNP ligands have still been rarely reported because of the difficulties in synthesis and the nature of air-sensitivity. Herein, we report a novel chiral PNP ligand (Heng-PNP) with both a rigid backbone and a bulky tert-butyl group on the phospholane motif. We successfully obtained its divalent iron complex. The chiral environment of its Ir(III) complex was also discussed with quadrant analysis. This tridentate ligand was applied in iridium-catalyzed asymmetric hydrogenation of challenging diaryl ketones: up to 98% ee and 500 TON are achieved. Computational study showed that the twist of conjugate aryl group in the substrate (induced by the special chiral pocket of Ir/Heng-PNP complex) leads to the energy difference in the enantiodetermining step.
- Wang, Heng,Zhang, Yao,Yang, Tilong,Guo, Xiaochong,Gong, Quan,Wen, Jialin,Zhang, Xumu
-
p. 8796 - 8801
(2020/11/13)
-
- Palladium(II)-catalyzed Intermolecular Cascade Cyclization of Methylenecyclopropanes with Aromatic Alkynes: Construction of Spirocyclic Compounds Containing Indene and 1,2-Dihydronaphthalene Moieties
-
A palladium(II)-catalyzed intermolecular cascade cyclization of methylenecyclopropanes with aromatic alkynes is reported in this paper. The reaction involves a migratory insertion of alkyne, an intramolecular Heck-type reaction, and β-H elimination, providing a series of spirocyclic compounds containing indene and 1,2-dihydronaphthalene moieties in moderate to excellent yields upon heating.
- Fang, Wei,Wei, Yin,Shi, Min
-
-
- Synthesis of Substituted Naphthalenes by 1,4-Palladium Migration Involved Annulation with Internal Alkynes
-
The palladium catalyzed annulation of 1-bromo-2-vinylbenzene derivatives with internal alkynes was realized for the efficient synthesis of substituted naphthalenes. A controllable aryl to vinylic 1,4-palladium migration process is the key for success.
- Wei, Dong,Hu, Tian-Jiao,Feng, Chen-Guo,Lin, Guo-Qiang
-
p. 743 - 748
(2018/07/25)
-
- Preparation method of indazole and application of indazole in medicine synthesis
-
The invention belongs to the field of chemicals, and relates to a preparation method of indazole and an application of the indazole in medicine synthesis. The invention discloses a preparation method of indazole and an application of the indazole in synthesizing 1H-indazole-3-carboxylic acid, lonidamine, a compound 8, a compound 9, a compound 10, axitinib, YD-3, YC-1 and similar substances thereof.
- -
-
-
- Dibenzo [c, i] [1,10] O-phenanthroline and its derivatives and preparation method
-
The invention discloses a dibenzo[c, i][1, 10]o-phenanthroline, its derivative and preparation method. The compound is characterized in that: two phenanthridines share a benzene ring, and the ortho-position of the nitrogen atom is equipped with a substituent group, which can be hydrogen, alkyl, phenyl or aryl. The preparation method includes: taking 4, 7-dibromobenzo[2, 1, 3]thiadiazole and 2-formyl phenylboronic acid or 2-acetyl(or arylformyl)phenylboronic acid pinacol ester as raw materials, carrying out Suzuki coupling reaction to obtain a series of 4, 7-di[2-formyl, 2-alkylformyl or arylformyl]benzo[2, 1, 3]thiadiazole, and finally carrying out reduction by sodium borohydride/cobalt chloride hexahydrate or lithium aluminum hydride and cyclization so as to obtain a series of dibenzo[c, i][1, 10]o-phenanthroline and its derivatives. The series of organic compounds provided by the invention broadens the scope of organic electroluminescent materials, and the preparation method provides a simple and convenient way for synthesis of phenanthroline series compounds. (formula).
- -
-
-
- Borylation of Olefin C-H Bond via Aryl to Vinyl Palladium 1,4-Migration
-
The aryl to vinyl palladium 1,4-migration was realized for the first time. The generated alkenyl palladium species was trapped by diboron reagents under Miyaura borylation conditions, providing a new method to synthesize β,β-disubstituted vinylboronates. The excellent regioselectivity and broad substrate scope were observed for this novel transformation.
- Hu, Tian-Jiao,Zhang, Ge,Chen, Ya-Heng,Feng, Chen-Guo,Lin, Guo-Qiang
-
p. 2897 - 2900
(2016/03/19)
-
- Copper(I) Oxide-Mediated Cyclization of o-Haloaryl N-Tosylhydrazones: Efficient Synthesis of Indazoles
-
An efficient synthesis of indazoles from readily accessible E/Z mixtures of o-haloaryl N-tosylhydrazones has been developed. The thermo-induced isomerization of N-tosylhydrazones is discussed. A series of valuable indazole derivatives are prepared in good yields, and the method has been successfully applied to the synthesis of the bioactive compounds, lonidamine, AF-2785, axitinib, YC-1 and YD-3.
- Tang, Meng,Kong, Yuanfang,Chu, Bingjie,Feng, Dan
-
p. 926 - 939
(2016/04/05)
-
- Erbium trifluoromethanesulfonate catalyzed Friedel-Crafts acylation using aromatic carboxylic acids as acylating agents under monomode-microwave irradiation
-
Erbium trifluoromethanesulfonate is found to be a good catalyst for the Friedel-Crafts acylation of arenes containing electron-donating substituents using aromatic carboxylic acids as the acylating agents under microwave irradiation. An effective, rapid and waste-free method allows the preparation of a wide range of aryl ketones in good yields and in short reaction times with minimum amounts of waste.
- Tran, Phuong Hoang,Hansen, Poul Erik,Nguyen, Hai Truong,Le, Thach Ngoc
-
p. 612 - 618
(2015/02/19)
-
- Palladium(II)-catalyzed desulfitative synthesis of aryl ketones from sodium arylsulfinates and nitriles: Scope, limitations, and mechanistic studies
-
A fast and efficient protocol for the palladium(II)-catalyzed production of aryl ketones from sodium arylsulfinates and various organic nitriles under controlled microwave irradiation has been developed. The wide scope of the reaction has been demonstrated by combining 14 sodium arylsulfinates and 21 nitriles to give 55 examples of aryl ketones. One additional example illustrated that, through the choice of the nitrile reactant, benzofurans are also accessible. The reaction mechanism was investigated by electrospray ionization mass spectrometry and DFT calculations. The desulfitative synthesis of aryl ketones from nitriles was also compared to the corresponding transformation starting from benzoic acids. Comparison of the energy profiles indicates that the free energy requirement for decarboxylation of 2,6-dimethoxybenzoic acid and especially benzoic acid is higher than the corresponding desulfitative process for generating the key aryl palladium intermediate. The palladium(II) intermediates detected by ESI-MS and the DFT calculations provide a detailed understanding of the catalytic cycle. (Figure Presented).
- Skillinghaug, Bobo,Sk?ld, Christian,Rydfjord, Jonas,Svensson, Fredrik,Behrends, Malte,S?vmarker, Jonas,Sj?berg, Per J. R.,Larhed, Mats
-
p. 12018 - 12032
(2015/01/16)
-
- CuII-catalyzed asymmetric hydrosilylation of diaryl- and aryl heteroaryl ketones: Application in the enantioselective synthesis of orphenadrine and neobenodine
-
With certain amounts of sodium tert-butoxide and tert-butanol as additives, catalytic amounts of an inexpensive and easy-to-handle copper source Cu(OAc)2·H2O, a commercially available and air-stable non-racemic dipyridylphosphine ligand, as well as the stoichiometric desirable hydride donor polymethylhydrosiloxane (PMHS), formed a versatile in situ catalyst system for the enantioselective reduction of a broad spectrum of prochiral diaryl and aryl heteroarylketones in air, in high yields and with good to excellent enantioselectivities (up to 96 %). In particular, the practical viability of this process was evinced by its successful applications in the asymmetric synthesis of optically enriched potent antihistaminic drugs orphenadrine and neobenodine. Copyright
- Sui, Yao-Zong,Zhang, Xi-Chang,Wu, Jun-Wen,Li, Shijun,Zhou, Ji-Ning,Li, Min,Fang, Wenjun,Chan, Albert S. C.,Wu, Jing
-
p. 7486 - 7492
(2012/07/27)
-
- A new paradigm for carbon-carbon bond formation: Aerobic, copper-templated cross-coupling
-
Thiol esters and boronic acids react to produce ketones under aerobic conditions in the presence of catalytic quantities of a CuI or CuII salt. The reaction occurs at reasonable rates between room temperature and 50 °C at neutral pH using thiol esters derived from bulky 2° amides of thiosalicylamides such as those based on N-tert-butyl-2-mercaptobenzamide. In this mechanistically unprecedented reaction system, the carbon-carbon bond formation occurs through templating of the thiol ester and the boronic acid at copper; the system is rendered catalytic in copper under the aerobic conditions. Copyright
- Villalobos, Janette M.,Srogl, Jiri,Liebeskind, Lanny S.
-
p. 15734 - 15735
(2008/09/20)
-
- STUDIES IN TRIFLUOROMETHANESULPHONIC ACID-IV KINETICS AND MECHANISM OF ACYLATION OF AROMATIC COMPOUNDS
-
A detailed kinetic study has been made of acylation reactions in solvent trifluoromethane sulphonic acid (CF3SO3H) using carboxylic acids as the electrophilic species involved.These species were shown to be probably the protonated form of the mixed anhydride.The reactions show high substrate selectivity characterised by high negative values of p+.Substituents in the carboxylic acids have a relatively small influence on the reactions rates due to a cancellation of substituents effects on the protonation of the mixed anhydride with those operating on the subsequent slow reaction of these species with the aromatic substrate.Anomalous effects were found for certain ortho substituents.The overall mechanism is discussed in terms of polar and steric effects in conjunction with the competing protonation of the aromatic bases, together with evidence from isotope effects.
- Roberts, R. M. G.,Sadri, A. R.
-
p. 137 - 142
(2007/10/02)
-