- Regioselective iodination of phenol and analogues using N-iodosuccinimide and p-toluenesulfonic acid
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Mild and highly regioselective monoiodination of phenol and analogues is achieved in high to excellent yields at room temperature with a combination of stoichiometric p-toluenesulfonic acid and N-iodosuccinimide.
- Bovonsombat, Pakorn,Leykajarakul, Juthamard,Khan, Chiraphorn,Pla-on, Kawin,Krause, Michael M.,Khanthapura, Pratheep,Ali, Rameez,Doowa, Niran
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- Total synthesis of (+)-linoxepin by utilizing the catellani reaction
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Molecular intelligence: The structurally novel lignan (+)-linoxepin is synthesized in an eight-step sequence. The enantioselective synthesis features the palladium-catalyzed Catellani reaction as the key step. In this highly convergent multicomponent reaction, two new carbon-carbon bonds are formed, one of which results from a C-H bond functionalization. Copyright
- Weinstabl, Harald,Suhartono, Marcel,Qureshi, Zafar,Lautens, Mark
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- Synthesis of Stannylated Aryl Imines and Amines via Aryne Insertion Reactions into Sn?N Bonds
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The reaction of in situ generated arynes with stannylated imines to provide ortho-stannyl-aniline derivatives is reported. The readily prepared trimethylstannyl benzophenone imine is introduced as an efficient reagent to realize the aryne σ-insertion reaction. The imine functionality is an established N-protecting group and insertions proceed with good yields and good to excellent regioselectivities. The product anilines are valuable starting materials for follow-up chemistry thanks to the rich chemistry offered by the trimethylstannyl moiety.
- Kran, Eva,Mück-Lichtenfeld, Christian,Daniliuc, Constantin G.,Studer, Armido
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p. 9281 - 9285
(2021/05/31)
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- Could London Dispersion Force Control Regioselective (2 + 2) Cyclodimerizations of Benzynes? YES: Application to the Synthesis of Helical Biphenylenes
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In recent years, London dispersion interactions, which are the attractive component of the van der Waals potential, have been found to play an important role in controlling the regio- and/or stereoselectivity of various reactions. Particularly, the dispersion interactions between substrates and catalysts (or ligands) are dominant in various selective catalyzes. In contrast, repulsive steric interactions, rather than the attractive dispersion interactions, between bulky substituents are predominant in most of the noncatalytic reactions. Herein, we demonstrate the first example of London dispersion-controlled noncatalytic (2 + 2) cyclodimerization of substituted benzynes to selectively afford proximal biphenylenes in high yields and regioselectivities, depending on the extent of dispersion interactions in the substituents. This method can be applied for the synthesis of novel helical biphenylenes, which would be fascinating for chemists as these compounds are potential skeletons for ligands, catalysts, and medicines.
- Akai, Shuji,Aoyama, Hiroshi,Fukumoto, Yutaka,Heguri, Akito,Ikawa, Takashi,Masuda, Yuto,Murakami, Tomonari,Shigeta, Yasuteru,Takagi, Akira,Tokiwa, Hiroaki,Yahata, Kenzo,Yamamoto, Yuta
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p. 10853 - 10859
(2021/07/26)
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- Application of the palladium-catalysed norbornene-assisted catellani reaction towards the total synthesis of (+)-linoxepin and isolinoxepin
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Our ongoing effort towards the development of highly selective transition-metal-catalysed C-H activation processes has led to the expansion of the Catellani reaction. In a Pd0/PdII/Pd IV-catalysed domino reaction, an aryl iodide, alkyl iodide and tert-butyl acrylate were combined to synthesize the carbon framework of the novel lignan (+)-linoxepin. The enantioselective synthesis highlights the work accomplished in our group and provides an excellent procedure for the reliable and scalable synthesis of architecturally complex scaffolds. This report outlines the synthetic approaches towards this interesting class of biologically active molecules. After the key Catellani/Heck reaction, our synthesis features a Leimeux-Johnson oxidation and a titanium tetrachloride mediated aldol condensation. Finally, a tuneable Mizoroki-Heck reaction was performed to furnish not only the natural product (+)-linoxepin but also its isoform, which we have named isolinoxepin. The enantioselective total synthesis of the natural product (+)-linoxepin has been accomplished in eight steps starting from commercial materials. The key Pd-catalysed Catellani step served to combine aryl iodide, alkyl iodide and tert-butyl acrylate in a domino sequence. By tuning the final Heck reaction, both the natural product and its structural isomer were synthesized. Copyright
- Qureshi, Zafar,Weinstabl, Harald,Suhartono, Marcel,Liu, Hongqiang,Thesmar, Pierre,Lautens, Mark
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p. 4053 - 4069
(2014/07/08)
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- The first total synthesis of tarennane, a potent antioxidant chalcone constituent from tarenna attenuate or Magnolia officinalis
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The convergent total synthesis of tarennane has been accomplished in six steps starting from commercially available phloroglucinol and guaiacol; the key step of the synthesis relies on a highly regioselective Heck reaction applying iodophenol and PdCl2(PPh3)2.
- Yang, Jincheng,Yang, Tao,Luo, Youfu,He, Jun,Shi, Jianyou,Peng, Aihua
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scheme or table
p. 258 - 263
(2012/04/18)
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- SPIROPYRROLIDINE BETA-SECRETASE INHIBITORS FOR THE TREATMENT OF ALZHEIMER'S DISEASE
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The present invention is directed to spiropyrrolidine compounds of formula (I) which are inhibitors of the beta-secretase enzyme and that are useful in the treatment of diseases in which the beta-secretase enzyme is involved, such as Alzheimer's disease.
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- Synthesis of piperidine derivatives by reduction of pyridinium salts
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Piperidine derivatives 1a-e and 2a-f have been prepared by the reduction of 3-and 4-substituted pyridinium salts with NaBH4 in moderate to excellent yields. The reactions regioselectively give 1,2,5,6-tetrahydropyridines, and the yields depend greatly upon the nature of substituents on the phenyl ring and on the nitrogen atom, the nature and the position of the substituents on the pyridyl ring, and the chain length between the aryloxy and the pyridyl groups. Copyright Taylor & Francis Group, LLC.
- Tang, Zilong,Mayrargue, Joelle,Alami, Mouad
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p. 3367 - 3379
(2008/02/13)
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- Synthesis of morphine fragments spiro[benzofuran-3(2H),4'-piperidine] and octahydro-1H-benzofuro[3,2-e]isoquinoline by intramolecular heck reaction
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As a better alternative to radical cyclization, 5-(2-bromo-6-methoxyphenoxy)-2-methyl-1 ,2,3,4,5,6,7,8-octahydroisoquinoline (2) and its 1-oxo analog 3 underwent Pd-catalyzed intramolecular cyclization to give the tetracyclic (ACNO) morphine fragments 5 and 6 respectively. 4-[(2'-Iodo-6'-methoxyphenoxy)methyl]-1-ethoxycarbonyl-1,2,5,6, -tetrahydropyridine (11) reacted similarly to provide the tricyclic ANO fragment 12 in 70% yield and 45% e.e. when a Pd-(S)-BINAP complex was used as the catalyst.
- Cheng, Chen-Yu,Liou, Jing-Ping,Lee, Mei-Jing
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p. 4571 - 4574
(2007/10/03)
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- Iodination of Thallium(I) salts of Phenols
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The iodination of thallium(I) salts of phenols is examined and the results are compared with those of the selective ortho-iodinating reagent thallium(I) acetate-iodine.
- Gambie, Richard C.,Larsen, David S.,Rutledge, Peter S.,Woodgate, Paul D.
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p. 767 - 769
(2007/10/03)
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- A general synthesis of dihydrobenzofurans by intramolecular conjugate addition
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ortho Iodophenoxy crotonates 3e-7e cyclize to dihydrobenzofurans 1 and 9-12 when subjected to lithium-iodine exchange at -100 deg C.Naphtofuran 13 can be similarly obtained from α-iodonaphtoxy crotonate 8e.Methylation of this reaction mixture in
- Weeratunga, Gamini,Jaworska-Sobiesiak, Alina,Horne, Stephen,Rodrigo, Russel
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p. 2019 - 2023
(2007/10/02)
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