- Palladium-Catalyzed Sequential Vinyl C–H Activation/Dual Decarboxylation: Regioselective Synthesis of Phenanthrenes and Cyclohepta[1,2,3-de]naphthalenes
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The application of a C(vinyl), C(aryl)-palladacycle from vinyl-containing substrates is challenging due to the interference of a reactive double bond in palladium catalysis. This Letter describes a [4 + 2] or [4 + 3] cyclization based on a C(vinyl), C(aryl)-palladacycle by employing α-oxocarboxylic acids as the insertion units under a palladium/air system. The reaction proceeded through the key vinyl C–H activation and dual decarboxylation sequence, forming phenanthrenes and cyclohepta[1,2,3-de]naphthalenes regioselectively in good yields. The synthetic versatility of this protocol is highlighted by the gram-scale synthesis and synthesizing functional material molecule.
- Jiang, Guomin,Ye, Hao,Shi, Lei,Dai, Hong,Wu, Xin-Xing
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p. 9398 - 9402
(2021/12/09)
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- Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis: Synthesis of Phenanthrenes via Phosphomolybdic Acid as a Catalyst
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Compared with the impressive achievements of catalytic carbonyl-olefin metathesis (CCOM) mediated by Lewis acid catalysts, exploration of the CCOM through Br?nsted acid-catalyzed approaches remains quite challenging. Herein, we disclose a synthetic protocol for the construction of a valuable polycycle scaffold through the CCOM with the inexpensive, nontoxic phosphomolybdic acid as a catalyst. The current annulations could realize carbonyl-olefin, carbonyl-alcohol, and acetal-alcohol in situ CCOM reactions and feature mild reaction conditions, simple manipulation, and scalability, making this strategy a promising alternative to the Lewis acid-catalyzed COM reaction.
- Chen, Yi,Jin, Yuan,Lin, Zhihua,Liu, Di,Shu, Mao,Tan, Jingyao,Tian, Lingfeng,Wang, Rui,Xu, Li,Zhang, Xiaoke
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supporting information
(2022/01/03)
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- AuCl3-Catalyzed Ring-Closing Carbonyl–Olefin Metathesis
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Compared with the ripeness of olefin metathesis, exploration of the construction of carbon–carbon double bonds through the catalytic carbonyl–olefin metathesis reaction remains stagnant and has received scant attention. Herein, a highly efficient AuCl3-catalyzed intramolecular ring-closing carbonyl–olefin metathesis reaction is described. This method features easily accessible starting materials, simple operation, good functional-group tolerance and short reaction times, and provides the target cyclopentenes, polycycles, benzocarbocycles, and N-heterocycle derivatives in good to excellent yields.
- Wang, Rui,Chen, Yi,Shu, Mao,Zhao, Wenwen,Tao, Maoling,Du, Chao,Fu, Xiaoya,Li, Ao,Lin, Zhihua
-
supporting information
p. 1941 - 1946
(2020/02/11)
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- A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
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Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
- Feng, Boya,Yang, Yudong,You, Jingsong
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p. 6031 - 6035
(2020/07/10)
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- Exhaustive Reduction of Esters Enabled by Nickel Catalysis
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We report a one-step procedure to directly reduce unactivated aryl esters into their corresponding tolyl derivatives. This is achieved by an organosilane-mediated ester hydrosilylation reaction and subsequent Ni/NHC-catalyzed hydrogenolysis. The resulting conditions provide a direct and efficient alternative to multi-step procedures for this transformation that often require the use of hazardous metal hydrides. Applications in the synthesis of -CD3-containing products, derivatization of bioactive molecules, and chemoselective reduction in the presence of other C-O bonds are demonstrated.
- Cook, Adam,Prakash, Sekar,Zheng, Yan-Long,Newman, Stephen G.
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supporting information
p. 8109 - 8115
(2020/05/20)
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- Preparation method of fused ring compound
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The invention discloses a preparation method of a fused ring compound III. The preparation method comprises the following step: in a solvent and in the presence of palladium acetate, alkali and a ligand, carrying out a reaction shown in the specification on a compound I and a compound II to obtain a compound III. The preparation method disclosed by the invention is relatively good in compatibilitywith a substrate, various polycyclic aromatic hydrocarbon compounds can be simply obtained in a short period of time through convergent synthesis, and particularly, heteroatom-containing polycyclic aromatic hydrocarbon shows extremely excellent regioselectivity.
- -
-
Paragraph 0116-0118; 0120; 0123
(2020/12/10)
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- Catalytic Dehydrogenative Cyclization of o-Teraryls under pH-Neutral and Oxidant-Free Conditions
-
A cobaloxime-catalyzed acceptorless dehydrogenative cyclization of o-teraryls was developed. In stark contrast to the established methods such as the Scholl or Mallory reactions, this method does not require any strong acids or oxidants, and shows high atom economy and a broad substrate scope. It operates at near room temperature with light as the source of energy. Acid- or oxidant-sensitive functional groups, such as 4-methoxyphenyl, unprotected benzyl alcohol, silyl ether, and thiophene groups are tolerated. Remarkably, aryls with electron-withdrawing groups, and electron-poor heteroarenes, such as pyridine and pyrimidine, can also react. Preliminary mechanistic study reveals that hydrogen gas is released during the reaction, and both light and the cobalt catalyst are important for the dehydrogenation step.
- Dong, Guangbin,Tsukamoto, Tatsuhiro
-
supporting information
p. 15249 - 15253
(2020/06/30)
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- Sequential Cross-Coupling/Annulation of ortho-Vinyl Bromobenzenes with Aromatic Bromides for the Synthesis of Polycyclic Aromatic Compounds
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A sequential cross-coupling/annulation of ortho-vinyl bromobenzenes with aromatic bromides was realized, providing a direct and modular approach to access polycyclic aromatic compounds. A vinyl-coordinated palladacycle was proposed as the key intermediate for this sequential process. Excellent chemoselectivity and regioselectivity were observed in this transformation. The practicability of this method is highlighted by its broad substrate scope, excellent functional group tolerance, and rich transformations associated with the obtained products.
- Wei, Dong,Li, Meng-Yao,Zhu, Bin-Bin,Yang, Xiao-Di,Zhang, Fang,Feng, Chen-Guo,Lin, Guo-Qiang
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supporting information
p. 16543 - 16547
(2019/11/03)
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- Method for synthesizing 6-methyl phenanthridine compound
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The present invention provides a method for synthesizing a 6-methyl phenanthridine compound. The method is as below: using a substituted azide terminal alkene compound represented by a formula I as astarting material, conducting a reaction in an organic solvent under the action of a copper catalyst and an oxidizing agent at 60 to 100 DEG C for 8 to 16 hours, and conducting post-treatment on the obtained reaction solution to obtain 6-methyl phenanthridine represented by a formula II and derivatives thereof, wherein the mass ratio of the substituted azide terminal alkene compound represented bythe formula I, the copper catalyst and the oxidizing agent is 1:(0.11-0.3):(1-3). The method of the present invention is safe and environmentally friendly, and does not generate waste water; the substrate has good adaptability and various substituents can be aromatized/methylated; the reaction conditions are mild, and the reaction can be carried out at a lower temperature; the raw materials do not need to be aromatized or methylated in advance; the reaction steps are simple; therefore, the method is a new route for synthesis of various 6-methyl phenanthridines containing substituents.
- -
-
Paragraph 0026; 0027; 0028; 0030-0032; 0034-0036
(2019/03/26)
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- Carbonyl-Olefin Metathesis Catalyzed by Molecular Iodine
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The carbonyl-olefin metathesis reaction could facilitate rapid functional group interconversion and allow construction of complicated organic structures. Herein, we demonstrate that elemental iodine, a very simple catalyst, can efficiently promote this chemical transformation under mild reaction conditions. Our mechanistic studies revealed intriguing aspects of the activation mode via molecular iodine and the iodonium ion that could change the previously established perception of catalyst and substrate design for the carbonyl-olefin metathesis reaction.
- Tran, Uyen P. N.,Oss, Giulia,Breugst, Martin,Detmar, Eric,Pace, Domenic P.,Liyanto, Kevin,Nguyen, Thanh V.
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p. 912 - 919
(2019/01/14)
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- Pd(II)-NHDC-Functionalized UiO-67 Type MOF for Catalyzing Heck Cross-Coupling and Intermolecular Benzyne-Benzyne-Alkene Insertion Reactions
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A novel palladium N-heterocyclic bis-carbene dicarboxylate ligand (Pd-NHDC-H2L) was successfully synthesized. In addition, an Pd-NHDC-containing UiO-67 type MOF (UiO-67-Pd-NHDC) was prepared on the basis of a size-matched ligand mixture of biphenyl-4,4′-dicarboxylic acid/Pd-NHDC-H2L (9/1) and ZrCl4 under solvothermal conditions. The obtained UiO-67-Pd-NHC MOF can be a highly heterogeneous catalyst to promote Heck cross-coupling and intermolecular benzyne-benzyne-alkene insertion reactions.
- Wei, Yong-Liang,Li, Yue,Chen, Yun-Qi,Dong, Ying,Yao, Jia-Jia,Han, Xin-Yue,Dong, Yu-Bin
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p. 4379 - 4386
(2018/04/25)
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- Ruthenium-catalyzed hydrogenation of carbocyclic aromatic amines: Access to chiral exocyclic amines
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The first highly enantioselective hydrogenation of carbocyclic aromatic amines has been successfully realized using in situ-generated chiral ruthenium complex as catalyst, affording facile access to chiral exocyclic amines with up to 98% ee.
- Yan, Zhong,Xie, Huan-Ping,Shen, Hong-Qiang,Zhou, Yong-Gui
-
supporting information
p. 1094 - 1097
(2018/02/23)
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- Oxidative, Iodoarene-Catalyzed Intramolecular Alkene Arylation for the Synthesis of Polycyclic Aromatic Hydrocarbons
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A catalytic, metal-free and chemoselective oxidative intramolecular coupling of arene and alkene C?H bonds is reported. The active hypervalent iodine (HVI) reagent, generated catalytically in situ from iodotoluene and meta-chloroperoxybenzoic acid (m-CPBA), reacts with o-vinylbiphenyls to generate polyaromatic hydrocarbons in up to 95 % yield. Experimental evidence suggests the reactions proceed though vinyliodonium and, possibly, vinylenephenonium intermediates.
- Zhao, Zhensheng,Britt, Liam H.,Murphy, Graham K.
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p. 17002 - 17005
(2018/11/01)
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- Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis inside a Self-Assembled Supramolecular Host
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Carbonyl–olefin metathesis represents a powerful yet underdeveloped method for the formation of carbon–carbon bonds. So far, no Br?nsted acid based method for the catalytic carbonyl–olefin metathesis has been described. Herein, a cocatalytic system based on a simple Br?nsted acid (HCl) and a self-assembled supramolecular host is presented. The developed system compares well with the current benchmark catalyst for carbonyl–olefin metathesis in terms of substrate scope and yield of isolated product. Control experiments provide strong evidence that the reaction proceeds inside the cavity of the supramolecular host. A mechanistic probe indicates that a stepwise reaction mechanism is likely.
- Catti, Lorenzo,Tiefenbacher, Konrad
-
supporting information
p. 14589 - 14592
(2018/01/27)
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- Ni-Catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents via C-S bond cleavage
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A Ni-catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents, accompanied by the cleavage of the C(aryl)-SMe bond, has been presented. This method is distinguished by its mild conditions and moderate functional group tolerance, such as hydroxyl, halogen, and heterocycles, which should provide a straightforward access to the modification of sulfur-containing molecules.
- Zhu, Dan,Shi, Lei
-
supporting information
p. 9313 - 9316
(2018/08/29)
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- Intramolecular Acetyl Transfer to Olefins by Catalytic C?C Bond Activation of Unstrained Ketones
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A rhodium-catalyzed intramolecular acetyl-group transfer has been achieved through a “cut and sew” process. The challenge arises from the existence of different competitive pathways. Preliminary success has been achieved with unstrained enones that contain a biaryl linker. The use of an electron-rich N-heterocycilc carbene (NHC) ligand is effective to inhibit undesired β-hydrogen elimination. Various 9,10-dihydrophenanthrene derivatives can be prepared with excellent functional-group compatibility. The 13C-labelling study suggests that the reaction begins with cleavage of the unstrained C?C bond, followed by migratory insertion and reductive elimination.
- Rong, Zi-Qiang,Lim, Hee Nam,Dong, Guangbin
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p. 475 - 479
(2018/02/21)
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- Methylation of Arenols through Ni-catalyzed C—O Activation with Methyl Magnesium Bromide
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Direct alkylation of arenols with alkyl organometallic reagents has never been approached. Herein we reported the first successful example of nickel-catalyzed methylation of arenols with methyl Grignard reagents to construct C(sp2)-C(sp3/
- Shi, Wen-Juan,Shi, Zhang-Jie
-
supporting information
p. 183 - 186
(2018/01/15)
-
- Tropylium-promoted carbonyl-olefin metathesis reactions
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The carbonyl-olefin metathesis (COM) reaction is a highly valuable chemical transformation in a broad range of applications. However, its scope is much less explored compared to analogous olefin-olefin metathesis reactions. Herein we demonstrate the use of tropylium ion as a new effective organic Lewis acid catalyst for both intramolecular and intermolecular COM and new ring-opening metathesis reactions. This represents a significant improvement in substrate scope from recently reported developments in this field.
- Tran, Uyen P.N.,Oss, Giulia,Pace, Domenic P.,Ho, Junming,Nguyen, Thanh V.
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p. 5145 - 5151
(2018/06/21)
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- Polycyclic Aromatic Hydrocarbons via Iron(III)-Catalyzed Carbonyl-Olefin Metathesis
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Polycyclic aromatic hydrocarbons are important structural motifs in organic chemistry, pharmaceutical chemistry, and materials science. The development of a new synthetic strategy toward these compounds is described based on the design principle of iron(III)-catalyzed carbonyl-olefin metathesis reactions. This approach is characterized by its operational simplicity, high functional group compatibility, and regioselectivity while relying on FeCl3 as an environmentally benign, earth-abundant metal catalyst. Experimental evidence for oxetanes as reactive intermediates in the catalytic carbonyl-olefin ring-closing metathesis has been obtained.
- McAtee, Christopher C.,Riehl, Paul S.,Schindler, Corinna S.
-
supporting information
p. 2960 - 2963
(2017/03/11)
-
- Facile Synthesis of Polycyclic Aromatic Hydrocarbons: Br?nsted Acid Catalyzed Dehydrative Cycloaromatization of Carbonyl Compounds in 1,1,1,3,3,3-Hexafluoropropan-2-ol
-
The cycloaromatization of aromatic aldehydes and ketones was readily achieved by using a Br?nsted acid catalyst in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP). In the presence of a catalytic amount of trifluoromethanesulfonic acid, biaryl-2-ylacetaldehydes and 2-benzylbenzaldehydes underwent sequential intramolecular cationic cyclization and dehydration to afford phenacenes and acenes, respectively. Furthermore, biaryl-2-ylacetaldehydes bearing a cyclopentene moiety at the α-position underwent unprecedented cycloaromatization including ring expansion to afford triphenylenes. HFIP effectively promoted the cyclizations by suppressing side reactions presumably as a result of stabilization of the cationic intermediates.
- Fujita, Takeshi,Takahashi, Ikko,Hayashi, Masaki,Wang, Jingchen,Fuchibe, Kohei,Ichikawa, Junji
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p. 262 - 265
(2017/01/24)
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- Intramolecular 10,10a-[2+2] photocycloaddition reactions of phenanthrenes with linked styrene
-
Intramolecular photocycloaddition reactions of styrene linked 9-cyanophenanthrenes led to formation of C-9 C-10 [2+2] cycloadducts which underwent cycloreversion under the prolonged irradiation conditions to regenerate the starting substrates. Unusual 8-membered ring products were irreversibly formed in these processes. Product distributions were governed by substituent controlled, donor-acceptor interactions that direct generation of two intramolecular singlet exciplexes, which serve as intermediates in the pathways to formation of 9,10- and 10,10a-[2+2] adducts.
- Maeda, Hajime,Nakashima, Ryota,Sugimoto, Akira,Mizuno, Kazuhiko
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p. 232 - 237
(2016/07/21)
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- Nickel-catalyzed cross-coupling of anisole derivatives with trimethylaluminum through the cleavage of carbonoxygen bonds
-
Nickel-catalyzed cross-coupling of methoxyarenes with trimethylaluminum is described. The use of 1,3-dicyclohexylimidazol-2-ylidene as a ligand and NaO'Bu as a base promotes the methylation of anisole derivatives via the cleavage of normally unreactive aryl carbonoxygen bonds.
- Morioka, Toshifumi,Nishizawa, Akihiro,Nakamura, Keisuke,Tobisu, Mamoru,Chatani, Naoto
-
supporting information
p. 1729 - 1731
(2016/02/19)
-
- Synthesis of Multisubstituted Triphenylenes and Phenanthrenes by Cascade Reaction of o-Iodobiphenyls or (Z)-β-Halostyrenes with o-Bromobenzyl Alcohols through Two Sequential C-C Bond Formations Catalyzed by a Palladium Complex
-
o-Bromobenzyl alcohol has been developed as a novel annulating reagent, bearing both nucleophilic and electrophilic substituents, for the facile synthesis of polycyclic aromatic hydrocarbons. A palladium/electron-deficient phosphine catalyst efficiently coupled o-iodobiphenyls or (Z)-β-halostyrenes with o-bromobenzyl alcohols to afford triphenylenes and phenanthrenes, respectively. The present cascade reaction proceeded through deacetonative cross-coupling and sequential intramolecular cyclization. An array of experimental data suggest that the reaction mechanism involves the equilibrium of 1,4-palladium migration.
- Iwasaki, Masayuki,Araki, Yasuhiro,Iino, Shohei,Nishihara, Yasushi
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p. 9247 - 9263
(2015/09/28)
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- Base-Promoted/Gold-Catalyzed Intramolecular Highly Selective and Controllable Detosylative Cyclization
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A highly selective, controllable and synthetically useful base-promoted intramolecular detosylative cyclization of bis-N-tosylhydrazones has been achieved, affording N-containing heterocycles and cyclic olefins under transition-metal-free or gold-catalyzed procedures, respectively. Moreover, an effective and practical metal-free or gold-catalyzed approach to synthesize polycyclic aromatic compounds is also reported. Basic cyclizations: A highly selective, controllable, and synthetically useful base-promoted intramolecular detosylative cyclization of bis-N-tosylhydrazones affords N-containing heterocycles and cyclic olefins under transition-metal-free or gold-catalyzed procedures, respectively. Moreover, an effective and practical metal-free or gold-catalyzed approach to synthesize polycyclic aromatic compounds is also reported.
- Zhu, Chenghao,Qiu, Lin,Xu, Guangyang,Li, Jian,Sun, Jiangtao
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p. 12871 - 12875
(2015/09/07)
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- KOt-Bu/DMF promoted intramolecular cyclization of 1,1′-biphenyl aldehydes and ketones: An efficient synthesis of phenanthrenes
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A new synthesis of phenanthrene derivatives has been achieved through intramolecular cyclization of 1,1′-biphenyl aldehydes and ketones promoted by KOt-Bu/DMF. A free radical reaction pathway is proposed.
- Chen, Yan-Yan,Zhang, Niu-Niu,Ye, Lin-Miao,Chen, Jia-Hua,Sun, Xiang,Zhang, Xue-Jing,Yan, Ming
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p. 48046 - 48049
(2015/06/16)
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- Bismuth-catalyzed synthesis of polycyclic aromatic hydrocarbons (PAHs) with a phenanthrene backbone via cyclization and aromatization of 2-(2-arylphenyl)vinyl ethers
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The reaction of 2-(2-arylphenyl)vinyl ethers in the presence of a catalytic amount of bismuth(III) triflate gave substituted phenanthrenes in excellent yields under mild reaction conditions. The reaction was also applied to the construction of other polycyclic aromatic hydrocarbons (PAHs), such as chrysene, helicene, and pyrene having a phenanthrene backbone, via regioselective cyclization. This method has the advantages of easy availability of the cyclization precursors, operational simplicity, and high reaction efficiency.
- Murai, Masahito,Hosokawa, Naoki,Roy, David,Takai, Kazuhiko
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supporting information
p. 4134 - 4137
(2014/09/30)
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- Gold-catalyzed 6-exo-dig cycloisomerization: A versatile approach to functionalized phenanthrenes
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A novel gold-catalyzed 6-exo-dig cycloisomerization of o-propargylbiaryls has been developed that provides ready access to functionalized phenanthrenes in largely good to excellent yields. Notable features of this method are readily available starting materials, mild reaction conditions, and broad substrate scope. Golden cat: A novel gold-catalyzed 6-exo-dig cycloisomerization of o-propargylbiaryls has been developed that provides ready access to functionalized phenanthrenes in largely good to excellent yields. Notable features of this method are readily available starting materials, mild reaction conditions, and broad substrate scope.
- Shu, Chao,Li, Long,Chen, Cheng-Bin,Shen, Hong-Cheng,Ye, Long-Wu
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p. 1525 - 1529
(2014/06/09)
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- Construction of polyaromatics via photocyclization of 2-(fur-3-yl) ethenylarenes, using a 3-furyl group as an isopropenyl equivalent synthon
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The construction of different types of substituted arenes was demonstrated through the photocyclization of 2-(fur-3-yl)ethenylarenes using a 3-furyl group as an isopropenyl equivalent synthon in the photocyclization reaction. The furan portion of the photocyclization intermediate could be fragmented via a base-induced elimination reaction to yield a series of substituted polyaromatics, including naphthalene, benzofuran, benzothiophene, phenanthrene, phenalene, acenaphthene, and triphenylene. Using different reagents, this method made it possible to introduce methyl or 2-hydroxyethyl groups as substituents at specific positions in these arenes.
- Chen, Ying-Zhe,Ni, Ching-Wen,Teng, Fu-Lin,Ding, Yi-Shun,Lee, Tunng-Hsien,Ho, Jinn-Hsuan
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p. 1748 - 1762
(2014/03/21)
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- Synthesis of acyclic ketones by catalytic, bidirectional homologation of formaldehyde with nonstabilized diazoalkanes. Application of a chiral diazomethyl(pyrrolidine) in total syntheses of erythroxylon alkaloids
-
This work offers a catalytic approach to convergent ketone assembly based upon formal and tandem C-H insertion of diazoalkanes in the presence of limiting amounts of monomeric formaldehyde, which is easily generated as a gas by thermolysis of the inexpensive and abundant paraformaldehyde (~30 USD/kg). The method forms di-, tri-, and even tetrasubstituted acetones with high efficiency, and it has streamlined a synthesis of (-)-dihydrocuscohygrine in which the absolute stereochemistry of a proline-based starting material is preserved. Assisted by the advent of new protocols for hydrazone oxidation, we also provide full details on handling non-carbonyl-stabilized diazo compounds.
- Wommack, Andrew J.,Kingsbury, Jason S.
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p. 10573 - 10587
(2013/11/19)
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- Synthesis of phenanthrenes by cationic chromium(III) porphyrin-catalyzed dehydration cycloaromatization
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Readily available biphenyl derivatives with ortho oxirane moiety react in the presence of cationic chromiun(III) porphyrin catalyst to afford phenanthrenes. The reaction is considered to be triggered by activation of the oxirane moiety through coordination to the Lewis acidic cationic chromium to give aldehyde via 1,2-hydride shift, which reacts with arene through intramolecular electrophilic aromatic substitution and subsequent dehydration. The reaction allows constructing a variety of polycyclic aromatic and heteroaromatic compounds.
- Wakabayashi, Ryota,Kurahashi, Takuya,Matsubara, Seijiro
-
supporting information
p. 2297 - 2301
(2013/11/06)
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- Direct arylation/alkylation/magnesiation of benzyl alcohols in the presence of grignard reagents via Ni-, Fe-, or Co-catalyzed sp3 C-O Bond activation
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Direct application of benzyl alcohols (or their magnesium salts) as electrophiles in various reactions with Grignard reagents has been developed via transition metal-catalyzed sp3 C-O bond activation. Ni complex was found to be an efficient catalyst for the first direct cross coupling of benzyl alcohols with aryl/alkyl Grignard reagents, while Fe, Co, or Ni catalysts could promote the unprecedented conversion of benzyl alcohols to benzyl Grignard reagents in the presence of nhexylMgCl. These methods offer straightforward pathways to transform benzyl alcohols into a variety of functionalities.
- Yu, Da-Gang,Wang, Xin,Zhu, Ru-Yi,Luo, Shuang,Zhang, Xiao-Bo,Wang, Bi-Qin,Wang, Lei,Shi, Zhang-Jie
-
supporting information
p. 14638 - 14641
(2012/11/07)
-
- Straightforward synthesis of phenanthrenes from styrenes and arenes
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Semi-one-pot synthesis of phenanthrenes from styrenes and arenes was developed through cross-dehydrogenative coupling. A sequence of Heck-type coupling and photo-cyclization were involved and a variety of functionalities were tolerated. This method provides an effective and practical protocol towards the synthesis of substituted phenanthrenes. The Royal Society of Chemistry 2012.
- Li, Hu,He, Ke-Han,Liu, Jia,Wang, Bi-Qin,Zhao, Ke-Qing,Hu, Ping,Shi, Zhang-Jie
-
supporting information; experimental part
p. 7028 - 7030
(2012/08/07)
-
- Rhodium(II)-catalyzed cyclization of bis(N-tosylhydrazone)s: An efficient approach towards polycyclic aromatic compounds
-
Ahead of the PAC: Polycyclic aromatic compounds (PACs) can be easily accessed by the combination of Suzuki-Miyaura cross-coupling and a [Rh 2(OAc)4]-catalyzed carbene reaction using easily available bis(N-tosylhydrazone)s as intermediates (see scheme; Ts=4-toluenesulfonyl). Copyright
- Xia, Ying,Liu, Zhenxing,Xiao, Qing,Qu, Peiyuan,Ge, Rui,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 5714 - 5717
(2012/07/28)
-
- Light-induced carbocyclization of iodoalkenes
-
The direct irradiation of iodoalkenes leads to the formation of carbon-centered radical by homolysis of the C-I bond. The photoreaction is used in cyclizations with formation of six membered rings.
- Campos-Gómez, Esther,Campos, Pedro J.,González, Héctor F.,Rodríguez, Miguel A.
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experimental part
p. 4292 - 4295
(2012/07/16)
-
- Manganese catalysts for C-H activation: An experimental/theoretical study identifies the stereoelectronic factor that controls the switch between hydroxylation and desaturation pathways
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We describe competitive C-H bond activation chemistry of two types, desaturation and hydroxylation, using synthetic manganese catalysts with several substrates. 9,10-Dihydrophenanthrene (DHP) gives the highest desaturation activity, the final products being phenanthrene (P1) and phenanthrene 9,10-oxide (P3), the latter being thought to arise from epoxidation of some of the phenanthrene. The hydroxylase pathway also occurs as suggested by the presence of the dione product, phenanthrene-9,10-dione (P2), thought to arise from further oxidation of hydroxylation intermediate 9-hydroxy-9,10- dihydrophenanthrene. The experimental work together with the density functional theory (DFT) calculations shows that the postulated Mn oxo active species, [Mn(O)(tpp)(Cl)] (tpp = tetraphenylporphyrin), can promote the oxidation of dihydrophenanthrene by either desaturation or hydroxylation pathways. The calculations show that these two competing reactions have a common initial step, radical H abstraction from one of the DHP sp3 C-H bonds. The resulting Mn hydroxo intermediate is capable of promoting not only OH rebound (hydroxylation) but also a second H abstraction adjacent to the first (desaturation). Like the active MnV=O species, this Mn IV-OH species also has radical character on oxygen and can thus give H abstraction. Both steps have very low and therefore very similar energy barriers, leading to a product mixture. Since the radical character of the catalyst is located on the oxygen p orbital perpendicular to the Mn IV-OH plane, the orientation of the organic radical with respect to this plane determines which reaction, desaturation or hydroxylation, will occur. Stereoelectronic factors such as the rotational orientation of the OH group in the enzyme active site are thus likely to constitute the switch between hydroxylase and desaturase behavior.
- Hull, Jonathan F.,Balcells, David,Sauer, Effiette L.O.,Raynaud, Christophe,Brudvig, Gary W.,Crabtree, Robert H.,Eisenstein, Odile
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supporting information; experimental part
p. 7605 - 7616
(2010/07/08)
-
- Cross-coupling reactions through the intramolecular activation of Alkyl(triorgano)silanes
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(Figure Presented) Cross-Si-ing the Jordan: Cross-coupling reactions of 2-(2-hydroxyprop-2-yl)phenylsubstituted alkylsilanes with a variety of aryl halides proceed in the presence of palladium and copper catalysts. The use of K3PO4 base allows for highly chemoselective alkyl coupling with both primary and secondary alkyl groups (Alk).
- Nakao, Yoshiaki,Takeda, Masahide,Matsumoto, Takuya,Hiyama, Tamejiro
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supporting information; experimental part
p. 4447 - 4450
(2010/08/19)
-
- Synthesis of 9,9′-biphenanthryl-10,10′-bis(oxazoline)s and their preliminary evaluations in the Friedel-Crafts alkylations of indoles with nitroalkenes
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Chiral 9,9′-biphenanthryl-10,10′-bis(oxazoline)s 6a-d were firstly prepared. These new chiral compounds were evaluated as ligands for the Friedel-Crafts alkylations of indoles with nitroalkenes, excellent yields and modest to good enantioselectivities were achieved.
- Lin, Shuang-zheng,You, Tian-pa
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experimental part
p. 1010 - 1016
(2009/04/10)
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- Flow-vacuum pyrolysis of dibenzocycloheptane annelated derivative on zeolites catalysts
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The pyrolysis of 5H-6,7-dihydrodibenzo[a,c]cyclohepten-6-ol (5) in FVP conditions, a method of thermal decomposition in advanced vacuum, inert atmosphere on zeolites/acid Al2O3 at variable temperature between 300- 350° C is presented. The reaction products were identified by GC/MS using authentic samples and a reaction mechanism involving cationic species as intermediates was proposed. A comparison with the pyrolysis of the same compound performed in FVP conditions on quartz is presented.
- Istrati, Daniela,Parvulescu, Luminitza,Popescu, Angela,Mihaiescu, Dan,Andrei, Elena,Badea, Florin
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p. 847 - 850
(2011/06/21)
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- Triflic acid promoted synthesis of polycyclic aromatic compounds
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The triflic acid (CF3SO3H) promoted cyclizations of 2-styrylbiaryls are found to be useful for the synthesis of polycyclic aromatic compounds, including functionalized derivatives of polycyclic aromatic compounds and heterocyclic sys
- Li, Ang,DeSchepper, Daniel J.,Klumpp, Douglas A.
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scheme or table
p. 1924 - 1927
(2009/09/05)
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- A novel nickel(0)-catalyzed cascade Ullmann-pinacol coupling: From o-bromobenzaldehyde to trans-9,10-dihydroxy-9,10-dihydrophenanthrene
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Using 5 mol% of (Ph3P)2NiCl2 as a catalyst, Zn powder as a reductant, ortho-carbonyl-substituted aryl halides could be coupled to form trans-9,10-dihydroxy-9,10-dihydrophenanthrenes in a one-pot cascade reaction. Georg Thieme Verlag Stuttgart.
- Lin, Shuang-Zheng,Chen, Qing-An,You, Tian-Pa
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p. 2101 - 2105
(2008/02/09)
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- Three-component coupling of benzyne: Domino intermolecular carbopalladation
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A new three-component coupling reaction of benzyne is described that uses two intermolecular carbopalladation reactions to produce 1,2-functionalized benzene derivatives. Copyright
- Henderson, Jaclyn L.,Edwards, Andrew S.,Greaney, Michael F.
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p. 7426 - 7427
(2007/10/03)
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- Flow-vacuum pyrolysis of polycyclic compounds. 24.1 pyrolysis of two dibenzocycloalkanols and their corresponding acetates
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The flow-vacuum pyrolyses of 6-hydroxymethyl-6H-5,7-dihydrodiben/o[a,c] cycloheptene (4), 6-methyl-6H-5,7-dihydro-dibenzo[a,c]cyclohepten-6-ol (5) and their corresponding acetates (6) and (7) were studied. The products' distributions were determined by GC/MS and the reaction mechanisms involving radical species were suggested, in order to explain the formation of the main reaction products.
- Istrati, Daniela,Parvulescu, Luminitza,Popescu, Angela,Mihaiescu, Dan,Draghici, Constantin,Marion, George,Simion, Alina
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p. 589 - 599
(2007/10/03)
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- Synthesis of substituted phenanthrenes via intramolecular condensation based on temperature-dependent deprotonation using a weak carbonate base
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Construction of substituted phenanthrenes via intramolecular condensation of 2′-methylbiphenyl-2-carbaldehydes using a mild base at 200 °C is described. The required high temperature can be quickly reached and easily maintained using microwave flash heating. Georg Thieme Verlag Stuttgart.
- Monsieurs, Katrien,Rombouts, Geert,Tapolcsányi, Pál,Mátyus, Péter,Maes, Bert U. W.
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p. 3225 - 3230
(2008/09/17)
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- Photoinduced ene-reaction of 9-methylene-9,10-dihydrophenanthrene with alkenes
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Irradiation of 9-methylene-9,10-dihydrophenanthrene (1) in the presence of 1,1-diphenylethene or styrene in benzene afforded ene-reaction adduct in good yield. In the absence of arylalkenes, the dimerized product of 1, 9-[2-(9-phenanthryl)ethyl]-9,10-dihydrophenanthrene, and 9-methylphenanthrene were obtained as major products.
- Sugimoto, Akira,Hiraoka, Ryoichi,Yasueda, Masahiro Kanayama,Mukae, Hirofumi,Mizuno, Kazuhiko
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p. 10883 - 10886
(2007/10/03)
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- Hydrous pyrolysis of methylphenanthrenes - Degradation and isomerization
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A simulation of the chemical transformations of methylphenanthrenes in sediment was performed using hydrous pyrolysis technique. The results indicate that isomerization is not the primary cause of the change in the MPI1 index. Rather, the degradation reaction of methylphenanthrenes to phenanthrene is one of the most likely causes reversing the trend of the MPI1 index with increasing the heating temperature. An unusual isomerization between 2-methylphenanthrene and 9-methylphenanthrene was also observed during the course of heating experiments. A plausible mechanism involving [1,5]-methyl shift was proposed for this isomerization reaction.
- Wu, Suh-Huey,Wang, Yane-Shih,Fan, Lian-Xin,Robert, T. D. Chang,Huang, Ded-Shih
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p. 315 - 317
(2007/10/03)
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- Evolution of products in the combustion of scrap tires in a horizontal, laboratory scale reactor
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A horizontal laboratory reactor was used to study the evolution of byproducts from the combustion of scrap tires at five nominal temperatures (ranging from 650 to 1050 °C) and different oxygen:sample ratios A model was used to calculate the bulk air ratio (λ), and the oxygen consumption was discussed considering this ratio λ. More than 100 volatile and semivolatile compounds were identified and quantified by gas chromatography mass spectrometry, plotting their yields vs the bulk air ratio and temperature. Five different behaviors considering the bulk air ratio and the temperature were identified.
- Fullana,Font,Conesa,Blasco
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p. 2092 - 2099
(2007/10/03)
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- Palladium-catalyzed controlled carbopalladation of benzyne
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2-Trimethylsilylphenyl trifluoromethanesulfonate 1a, a benzyne precursor, reacted with the allylic chlorides 2a - f in the presence of CsF (2.0 equiv) and Pd2(dba)3·CHCl3 (2.5 mol %)-dppf (5 mol %) in a 1:1 mixed solvent of CH3CN and THF to produce the phenanthrene derivatives 3 along with their minor regioisomers 4 in good yields (i) and the reaction of 1a with 2a and the internal alkynes 15a,c - e afforded the naphthalene derivatives 16 in moderate yields (ii). The reaction of benzyne precursor 1a with the alkynes 15a - c,f - h in the presence of Pd(OAc)2 (5 mol %)-(o-tolyl)3P (5 mol %) catalyst and CsF (2.0 equiv) in CH3CN gave the phenanthrene derivatives 17 (iii), whereas the reaction of 1a with the alkynes 15a,b,i in the presence of the same catalysts and CsF in CH3CN - toluene gave the indene derivatives 18 in good yields (iv). Detailed mechanistic investigation revealed that the former two reactions i and ii proceed through carbopalladation to free benzyne, while the latter two reactions iii and iv proceed through the nonfree benzyne mechanism, in which the initial step of the catalytic cycle begins with Pd(0) insertion to the Ar - OTf bond of 1.
- Yoshikawa, Eiji,Radhakrishnan,Yamamoto, Yoshinori
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p. 7280 - 7286
(2007/10/03)
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- A new parameter for maturity determination of organic matter in sediments based on the clay-catalyzed thermal isomerization of monomethylphenanthrenes
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Monomethylphenanthrenes (MPs) were isomerized by heating in the presence of Na-montmorillonite at 250 - 400 °C. Isomerization between 1- and 2-MP was found to proceed faster than those between the other sets of MPs. On the basis of this facile interconversion, the molar ratio of 1- to 2-MP was suggested to be a useful new parameter for the maturity assessment of sedimentary organic matter. This parameter was tested in a geochemical study on Miocene to Pliocene sediments in the Shinjo basin of Yamagata Prefecture. We determined the molar ratio in 12 depth-differing sediments, and found an almost linearly decreasing trend in the ratio with increasing depth, showing a good correlation of this parameter to the maturity of the sedimentary organic matter.
- Nomoto, Shinya,Hagiwara, Masayosi,Nakano, Yoshinobu,Shimoyama, Akira
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p. 1437 - 1443
(2007/10/03)
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- Palladium-catalyzed intermolecular controlled insertion of benzyne- benzyne-alkene and benzyne-alkyne-alkene - Synthesis of phenanthrene and naphthalene derivatives
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Aryne reagents, unlike alkynes, undergo insertion by allyl palladium complexes. The verification of the conversion described here is shown using Equation (1) as an example. The reaction proceeds in a few hours in refluxing acetonitrile to give the phenanthrene derivative in up to 71% yield.
- Yoshikawa, Eiji,Yamamoto, Yoshinori
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p. 173 - 175
(2007/10/03)
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- A novel method for the synthesis of substituted naphthalenes and phenanthrenes
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A new method for the synthesis of substituted naphthalenes and phenanthrenes was discussed. A formal synthesis of tanshinone I was also studied. Natural products that contain a naphthalene or phenanthrene nucleus often exhibit biological activity, which makes them attractive targets in organic synthesis. The results showed that the reaction can be proceed through at least two different pathways.
- De Koning, Charles B.,Michael, Joseph P.,Rousseau, Amanda L.
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p. 787 - 797
(2007/10/03)
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