- Domino Carbopalladation/C-H Activation as a Quick Access to Polycyclic Frameworks
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A new type of domino reaction for synthesis of heterocycles fusing the important bioactive cores, such as oxindole, indoline, and isoquinoline, is presented. Upon exposure to the very common palladium catalyst, the conceptually designed N-alkenyl iodobiaryls undergo a sequential carbopalladation/C-H activation to build polycyclic frameworks. These novel unique frameworks may provide structure sources in fragment-based drug discovery.
- Saha, Nemai,Wang, Haiwen,Zhang, Shengyi,Du, Yongliang,Zhu, Daqian,Hu, Yumin,Huang, Peng,Wen, Shijun
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- FORMATION OF BOTH METHYLENEDIOXY GROUPS IN THE ALKALOID (S)-STYLOPINE ISCATALYZED BY CYTOCHROME P-450 ENZYMES
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Two higly stereospecific microsomal cytochrome P-450 NADPH depedent enzymes have been discovered and characterized wich are responsible for the methylenedioxy group formation from (S)-scoulerine via (S)-cheilanthifoline to (S)-stylopine.
- Bauer, W.,Zenk, M.H.
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- Electrochemically enabled rhodium-catalyzed [4 + 2] annulations of arenes with alkynes
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Herein, electrochemically driven, Rh(iii)-catalyzed regioselective annulations of arenes with alkynes have been established. The strategy, combining the use of a rhodium catalyst with electricity, not only avoids the need for using a stoichiometric amount of external oxidant, but also ensures that the transformations proceed under mild and green conditions, which enable broad functional group compatibility with a variety of substrates, including drugs and pharmaceutical motifs. Moreover, the electrolysis reaction was made operationally simple by employing an undivided cell, and proceeds efficiently in aqueous solution in air. This journal is
- Chen, Jia-Yi,Li, Ming,Li, Rui-Tao,Ma, Qiang,Ni, Shao-Fei,Wang, Zi-Chen,Wen, Li-Rong,Zhang, Lin-Bao
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supporting information
p. 9515 - 9522
(2021/12/09)
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- Deuterated phenyl containing triazine compound and applications thereof, and organic electroluminescent device
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The invention relates to the field of organic light emitting devices, and discloses a deuterated phenyl containing triazine compound and applications thereof, and an organic electroluminescent device.The triazine compound has a structure which is shown as a formula (I); R1 and R2 are respectively and independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted fluorenyl, a substituted or unsubstituted dibenzothiophene group, and a substituted or unsubstituted dibenzofuran group. Current efficiency, brightness and service life can be effectively enhanced when the compound is used as the host material of a luminous layer. The structure of the compound is shown as the formula (I).
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Paragraph 0120; 0121; 0126; 0127
(2019/04/10)
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- Pd(II)-Catalyzed Synthesis of Alkylidene Phthalides via a Decarbonylative Annulation Reaction
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An unprecedented Pd(II)-catalyzed decarbonylative C-H/C-C activation and annulation reaction, which proceeds via intramolecular cyclization, is reported. This reaction of hydroxynaphthoquinones with disubstituted alkynes provides good yields of substituted alkylidene phthalides, which are the key intermediates for the synthesis of bioactive natural products.
- Borthakur, Somadrita,Baruah, Swagata,Sarma, Bipul,Gogoi, Sanjib
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p. 2768 - 2771
(2019/04/16)
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- Arylation/Intramolecular Conjugate Addition of 1,6-Enynes Enabled by Manganese(I)-Catalyzed C-H Bond Activation
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An arylation/intramolecular conjugate addition of cyclohexadienone-containing 1,6-enynes has been established through initiation by manganese(I)-catalyzed C-H bond activation. This tandem reaction involved unusual E/Z-isomerized alkenyl-Mn intermediates and proceeded smoothly with high chemoselectivities and perfect atom economy. The cyclization products could be further transformed to various structures. Mechanistic studies suggested that cleavage of the C-H bond was involved in the turnover-limiting step, and a manganese carbene anion intermediate was proposed to explain such an E/Z isomerization process.
- Tan, Yun-Xuan,Liu, Xing-Yu,Zhao, Yi-Shuang,Tian, Ping,Lin, Guo-Qiang
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supporting information
p. 5 - 9
(2018/11/23)
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- Acetic Acid-Promoted Rhodium(III)-Catalyzed Hydroarylation of Terminal Alkynes
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Rhodium(III)-catalyzed hydroarylation of terminal alkynes has not previously been achieved because of the inevitable oligomerization and other side reactions. Here, we report a novel Cp?Rh(III)-catalyzed hydroarylation of terminal alkynes in acetic acid as solvent to facilitate the C-H bond activation and subsequent transformations. This reaction proceeds under mild conditions, providing an effective approach to the synthesis of alkenylated heterocycles in high to excellent yields (31-99%) with a broad substrate scope (37 examples) and good functional-group compatibility. In this transformation, the loading of the alkyne can be reduced to 1.2 equivalents, which indicates the significant role of HOAc in lowering the reaction temperature and suppressing the oligomerization of the terminal alkyne. Preliminary mechanistic studies are also presented.
- Duan, Chang-Lin,Liu, Xing-Yu,Tan, Yun-Xuan,Ding, Rui,Yang, Shiping,Tian, Ping,Lin, Guo-Qiang
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supporting information
p. 932 - 938
(2019/05/10)
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- Directed: Ortho C-H borylation catalyzed using Cp?Rh(iii)-NHC complexes
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Cp?Rh(NHC) complexes with bulky chiral bidentate NHC-carboxylate ligands were efficiently synthesized and fully characterized including solid-state structures. These unprecedented rhodium(iii) complexes demonstrated high selectivity in pyridine-directed ortho-C-H borylation of arenes under mild conditions.
- Thongpaen, Jompol,Schmid, Thibault E.,Toupet, Loic,Dorcet, Vincent,Mauduit, Marc,Baslé, Olivier
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p. 8202 - 8205
(2018/07/29)
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- Rhodium-Catalyzed Regioselective Synthesis of Isoindolium Salts from 2-Arylpyridines and Alkenes in Aqueous Medium under Oxygen
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A highly regioselective synthesis of pyrido[2,1-a]isoindolium salts from 2-arylpyridines and two equivalents of electron-deficient alkenes catalyzed by rhodium is demonstrated. The reaction was carried out in aqueous medium at 110 °C using inexpensive oxygen as oxidant. Reverse aza-Michael addition of the isoindolium salt occurs when the salt was treated with base to give a β-disubstituted alkene product. A reaction mechanism involving an ortho C–H olefination of 2-arylpyridine by alkene, intramolecular aza-Michael addition, deprotonation at the β-carbon of the alkene fragment followed by another Michael addition to give the final product is proposed. (Figure presented.).
- Upadhyay, Nitinkumar Satyadev,Jayakumar, Jayachandran,Cheng, Chien-Hong
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supporting information
p. 3381 - 3386
(2016/11/13)
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- Cascade C-H Functionalization/Amidation Reaction for Synthesis of Azepinone Derivatives
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A cascade C-H functionalization/amidation reaction of aminobiaryls with diazomalonates has been developed under rhodium catalysis, affording new azepinone derivatives in moderate to excellent yields.
- Bai, Peng,Huang, Xing-Fen,Xu, Guo-Dong,Huang, Zhi-Zhen
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supporting information
p. 3058 - 3061
(2016/07/13)
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- Synthesis of Fluorenes Starting from 2-Iodobiphenyls and CH2Br2 through Palladium-Catalyzed Dual C-C Bond Formation
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A facile and efficient approach is developed for the synthesis of fluorene and its derivatives starting from 2-iodobiphenyls and CH2Br2. A range of fluorene derivatives can be synthesized under relatively mild conditions. The reaction proceeds via a tandem palladium-catalyzed dual C-C bond formation sequence through the key dibenzopalladacyclopentadiene intermediates, which are obtained from 2-iodobiphenyls through palladium-catalyzed C-H activation.
- Shi, Guangfa,Chen, Dushen,Jiang, Hang,Zhang, Yu,Zhang, Yanghui
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supporting information
p. 2958 - 2961
(2016/07/06)
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- Palladium-Catalyzed Cascade Arene/Alkyne Annulation: Synthesis of Fluorene-Benzoxazine Derivatives
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A palladium-catalyzed cascade arene/alkyne annulation reaction for the synthesis of fluorene-benzoxazine derivatives is developed. This transformation involves a 6-exo-dig cyclization, a 1,3-oxazine vinylpalladium intermediate, and a C-H bond activation.
- Cai, Zhong-Jian,Li, Fang-Hui,Wang, Shun-Yi,Ji, Shun-Jun
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supporting information
p. 4810 - 4813
(2016/10/14)
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- Synthesis of indolines by copper-mediated intramolecular aromatic C-H amination
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A Cu(OAc)2-mediated intramolecular aromatic C-H amination proceeds with the aid of a picolinamide-type bidentate coordination group to deliver the corresponding indolines in good yields. The reaction occurs smoothly even under noble-metal-free conditions, and in some cases the use of an MnO2 terminal oxidant renders the process catalytic in Cu. The mild oxidation aptitude of Cu(OAc)2 and/or MnO2 accommodates the formation of electron-rich thiophene-and indole-fused indoline analogues. The Cu-based system can provide an effective approach to various indolines of potent interest in pharmaceutical and medicinal chemistry.
- Takamatsu, Kazutaka,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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p. 3242 - 3249
(2015/03/30)
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- Transition-metal-free synthesis of phenanthridinones from biaryl-2-oxamic acid under radical conditions
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Na2S2O8-promoted decarboxylative cyclization of biaryl-2-oxamic acid for phenanthridinones has been developed. This work illustrates the first example of intramolecular decarboxylative amidation of unactivated arene under transition-metal-free conditions. Additionally, this approach provides an efficient and economical method to access biologically interesting phenanthridinones, an important structure motif in many natural products. (Chemical Equation Presented).
- Yuan, Ming,Chen, Li,Wang, Junwei,Chen, Shenjie,Wang, Kongchao,Xue, Yongbo,Yao, Guangmin,Luo, Zengwei,Zhang, Yonghui
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supporting information
p. 346 - 349
(2015/02/19)
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- Photocatalytic Dehydrogenative Lactonization of 2-Arylbenzoic Acids
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A metal-free dehydrogenative lactonization of 2-arylbenzoic acids at room temperature was developed. This work illustrates the first application of visible-light photoredox catalysis in the preparation of benzo-3,4-coumarins, an important structural motif in bioactive molecules. The combination of photocatalyst [Acr+-Mes] with (NH4)2S2O8 as a terminal oxidant provides an economical and environmentally benign entry to different substituted benzocoumarins. Preliminary mechanistic studies suggest that this reaction most likely occurs through a homolytic aromatic substitution pathway.
- Ramirez, Nieves P.,Bosque, Irene,Gonzalez-Gomez, Jose C.
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supporting information
p. 4550 - 4553
(2015/09/28)
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- Pd-catalyzed π-chelation assisted ortho-C-H activation and annulation of allylarenes with internal alkynes
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The synthesis of highly substituted naphthalenes from allylarenes and alkynes is described. This reaction proceeds via π-coordination of an allylic carbon-carbon double bond to the Pd(II) center and is followed by ortho selective C-H bond activation.
- Gandeepan, Parthasarathy,Cheng, Chien-Hong
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supporting information
p. 2084 - 2087
(2013/06/05)
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- RhIII-catalyzed C-H activation: A versatile route towards various polycyclic pyridinium salts
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An efficient and convenient method for the synthesis of highly substituted polycyclic pyridinium salts from the reaction of various 2-aryl-pyr-idines and 2-aryl-sp2-nitrogen-atom-containing heterocycles with alkynes through rhodium(III)-catalyzed C-H activation and annulation under an O2 atmosphere is described. A possible mechanism that involves the chelation-assisted C-H activation of the 2-arylpyridine substrate, insertion of the alkyne, and reductive elimination is proposed. This mechanism was supported by the isolation of a five-mem-bered rhodacycle (I'). In addition, kinetic isotope studies were performed to understand the intimate reaction mechanism.
- Luo, Ching-Zong,Gandeepan, Parthasarathy,Jayakumar, Jayachandran,Parthasarathy, Kanniyappan,Chang, Yu-Wei,Cheng, Chien-Hong
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supporting information
p. 14181 - 14186
(2013/11/06)
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- Mn-catalyzed aromatic C-H alkenylation with terminal alkynes
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The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese.
- Zhou, Bingwei,Chen, Hui,Wang, Congyang
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supporting information
p. 1264 - 1267
(2013/03/14)
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- Allylic carbon-carbon double bond directed pd-catalyzed oxidative ortho -olefination of arenes
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Pd-catalyzed selective ortho-olefination of arenes assisted by an allylic C-C double bond at room temperature using O2 as a terminal oxidant is described. A possible mechanism involving the initial coordination of allylic C=C bond to Pd followed by selective o-C-H bond metalation is proposed.
- Gandeepan, Parthasarathy,Cheng, Chien-Hong
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supporting information; experimental part
p. 5738 - 5741
(2012/05/07)
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- Free-amine-directed alkenylation of C(sp2)-H and cycloamination by palladium catalysis
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A new protocol for the palladium-catalyzed free-amine-directed alkenylation of C(sp2)-H bonds and cycloamination is described. Substituted biaryl-2-amines react with various alkenes, including electron-deficient alkenes, aryl alkenes and alkyl alkenes, to give the corresponding phenanthridines with exclusive regioselectivity. The use of α-branched styrenes leads to the formation of tricyclic compounds with a seven-membered amine ring. The method operates through a free-amine-directed alkenylation and a subsequent hydroamination cyclization reaction. Seven-membered cycloamination: A new protocol for the palladium-catalyzed free-amine-directed alkenylation of C(sp2)-H bonds and subsequent cycloamination is described (see scheme). Substituted biaryl-2-amines react with various alkenes to give the corresponding phenanthridines with exclusive regioselectivity. The use of α-branched styrenes leads to the formation of tricyclic compounds with a seven-membered amine ring. Copyright
- Liang, Zunjun,Ju, Long,Xie, Yongju,Huang, Lehao,Zhang, Yuhong
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supporting information
p. 15816 - 15821
(2013/01/16)
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- Characterization of two methylenedioxy bridge-forming cytochrome P450-dependent enzymes of alkaloid formation in the Mexican prickly poppy Argemone mexicana
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Formation of the methylenedioxy bridge is an integral step in the biosynthesis of benzo[c]phenanthridine and protoberberine alkaloids in the Papaveraceae family of plants. This reaction in plants is catalyzed by cytochrome P450-dependent enzymes. Two cDNAs that encode cytochrome P450 enzymes belonging to the CYP719 family were identified upon interrogation of an EST dataset prepared from 2-month-old plantlets of the Mexican prickly poppy Argemone mexicana that accumulated the benzo[c]phenanthridine alkaloid sanguinarine and the protoberberine alkaloid berberine. CYP719A13 and CYP719A14 are 58% identical to each other and 77% and 60% identical, respectively, to stylopine synthase CYP719A2 of benzo[c]phenanthridine biosynthesis in Eschscholzia californica. Functional heterologous expression of CYP719A14 and CYP719A13 in Spodoptera frugiperda Sf9 cells produced recombinant enzymes that catalyzed the formation of the methylenedioxy bridge of (S)-cheilanthifoline from (S)-scoulerine and of (S)-stylopine from (S)-cheilanthifoline, respectively. Twenty-seven potential substrates were tested with each enzyme. Whereas CYP719A14 transformed only (S)-scoulerine to (S)-cheilanthifoline (Km 1.9 ± 0.3; kcat/Km 1.7), CYP719A13 converted (S)-tetrahydrocolumbamine to (S)-canadine (Km 2.7 ± 1.3; kcat/Km 12.8), (S)-cheilanthifoline to (S)-stylopine (Km 5.2 ± 3.0; kcat/Km 2.6) and (S)-scoulerine to (S)-nandinine (Km 8.1 ± 1.9; k cat/Km 0.7). These results indicate that although CYP719A14 participates in only sanguinarine biosynthesis, CYP719A13 can be involved in both sanguinarine and berberine formation in A. mexicana.
- Diaz Chavez, Maria Luisa,Rolf, Megan,Gesell, Andreas,Kutchan, Toni M.
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experimental part
p. 186 - 193
(2012/02/14)
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- Palladium-catalyzed intermolecular decarboxylative coupling of 2-phenylbenzoic acids with alkynes via C-H and C-C bond activation
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A novel protocol for palladium-catalyzed intermolecular formal [4 + 2] annulation of 2-phenylbenzoic acids with alkynes is described. Acridine is shown to be essential for the high reaction efficiency. Phenanthrene derivatives are formed in moderate to good yields without coupling (pseudo)halides or organometallic species.
- Wang, Congyang,Rakshit, Souvik,Glorius, Frank
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supporting information; experimental part
p. 14006 - 14008
(2010/12/24)
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- Novel Iridium Complex and Organic Electroluminescence Device Using the Same
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Disclosed are a deuterated novel iridium complex phosphorescent material used as a light-emitting layer material of an organic electroluminescence device, a preparation method thereof and an organic electroluminescence device using the same. Compared with an organic electroluminescence device using the prior art light-emitting layer with no deuterium substitution, the organic electroluminescence device using the deuterated material of the present invention has improved luminescence efficiency, luminance, power efficiency, thermal stability and the like.
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Page/Page column 3-4; 7
(2008/12/07)
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- Ketopyrroles useful as ligands in organic iridium compositions
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The present invention provides novel ketopyrroles having structure XXIV wherein R2 is independently at each occurrence a deuterium atom, a halogen, a nitro group, an amino group, a C3-C40 aromatic radical, a C1-C50 aliphatic radical, or a C3-C40 cyclcoaliphatic radical; “a” is an integer from 0 to 3; and X1 and X2 are independently at each occurrence a bromine atom, a hydroxy group, or the group OR10, and wherein the group R10 is independently at each occurrence a deuterium atom, a halogen, a nitro group, an amino group, a C3-C40 aromatic radical, a C1-C50 aliphatic radical, or a C3-C40 cyclcoaliphatic radical. Ketopyrroles XXIV are useful ligands for the preparation of Type (1) and Type (2) organic iridium compositions. In one aspect, the present invention provides deuterated analogs of XXIV. Organic iridium compositions are useful in the preparation optoelectronic devices, such as OLED devices and photovoltaic devices exhibiting enhanced performance characteristics.
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Page/Page column 48
(2008/06/13)
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- NOVEL DEUTERATED ARYL AMINE COMPOUND, PREPARATION METHOD THEREOF, AND ORGANIC LIGHT EMITTING DIODE USING THE SAME
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Disclosed are a novel deuterated aryl amine compound capable of enhancing thermal stability, hole transporting capability, luminescence efficiency, etc. of an organic light emitting diode at the time of being used as a hole-injecting layer, a preparation method thereof, and an organic light emitting diode using the same.
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Page/Page column 7-8
(2008/06/13)
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