- Catalytic Asymmetric Addition of Diorganozinc Reagents to Pyrazole-4,5-Diones and Indoline-2,3-Diones
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The catalytic enantioselective diorganozinc additions to cyclic diketones including pyrazolin-4,5-diones and isatins have been developed. In the presence of morpholine-containing chiral amino alcohol ligand, the corresponding chiral cyclic tertiary alcohols were produced in good to excellent yields (up to 97 %) and enantioselectivities (up to 95 % ee). The notable feature of this protocol includes its mild reaction conditions, Lewis acid additives free and broad functional group tolerance.
- Wang, Rong-Hui,Li, Ya-Ling,He, Hong-Jiao,Xiao, You-Cai,Chen, Fen-Er
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supporting information
p. 4302 - 4306
(2021/02/16)
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- Experimental and Computational Studies on Cp*CyRh(III)/KOPiv-Catalyzed Intramolecular Dehydrogenative Cross-Couplings for Building Eight-Membered Sultam/Lactam Frameworks
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Described herein is an unusual Cp*CyRh(III)-catalyzed intramolecular site-specific aryl C-H annulation, a highly chemoselective protocol providing direct access to eight-membered sultams/lactams with broad substrate/functional group tolerance. Experimental and computational studies reveal that such a transformation involves a unique PivOH-assisted aryl C-H activation/alkene insertion/β-H elimination/hydrogen-transfer process involving the Rh(III)-hydride species as the active intermediate with the concomitant release of H2 as the major byproduct, thus enabling the developed Cp*CyRh(III) catalysis with redox-neutral and highly atom-economical features.
- Li, Liping,Gao, Hui,Sun, Ming,Zhou, Zhi,Yi, Wei
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p. 5473 - 5478
(2020/07/14)
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- Copper-Catalyzed Chemoselective Cyclization Reaction of 2-Isocyanoacetophenone: Synthesis of 4-Hydroxyquinoline Compounds
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A copper-catalyzed intramolecular cyclization reaction of 2-isocyanoacetophenone derivatives to afford 4-hydroxyquinolines chemoselectively is described. The transformation proceeds through enol tautomerism and a subsequent C-C bond formation. Compared to previous methods, this study provides a new protocol for the construction of 4-hydroxyquinoline compounds from functionalized isocyanides under mild conditions.
- Yuan, Qing,Rao, Weidong,Wang, Shun-Yi,Ji, Shun-Jun
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p. 1279 - 1284
(2020/01/22)
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- Pd-catalyzed regiodivergent synthesis of diverse oxindoles enabled by the versatile heck reaction of carbamoyl chlorides
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We report herein a miscellaneous oxindole synthesis bearing an all-carbon quaternary center, enabled by Pd-catalyzed intramolecular cyclization followed by multiple intermolecular Heck reactions of both easily accessible alkene-tethered carbamoyl chlorides and olefins. This protocol obviates the use of prefunctionalized olefinic reagents, exhibits excellent functional group tolerance, and features fascinating reactive versatility.
- Wu, Xianqing,Tang, Zaiquan,Zhang, Chengxi,Wang, Chenchen,Wu, Licheng,Qu, Jingping,Chen, Yifeng
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supporting information
p. 3915 - 3921
(2020/06/08)
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- Catalyst-free geminal aminofluorination of ortho-sulfonamide-tethered alkylidenecyclopropanes via a Wagner-Meerwein rearrangement
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A catalyst-free intramolecular geminal aminofluorination of ortho-sulfonamide-tethered alkylidenecyclopropanes has been developed. The reaction proceeded through two SET processes with Selectfluor to give a fluorinated cyclopropylcarbinyl cation and a further Wagner-Meerwein rearrangement to generate a cyclobutyl carbocation, which undergoes intramolecular nucleophilic capture by amide to forge fluorinated cyclobuta[b]indoline derivatives. A polycyclic multi-fluorinated byproduct was also formed through a Ritter-type reaction in some cases.
- Fan, Xing,Wang, Qiang,Wei, Yin,Shi, Min
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supporting information
p. 10503 - 10506
(2018/09/21)
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- Photo-Fries rearrangement of aryl acetamides: Regioselectivity induced by the aqueous micellar green environment
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Photochemical reactions tend to give more than one photoproduct. However, such a reaction can be a powerful synthetic tool when it is possible to conduct it in regioselective conditions yielding a single photoproduct. Water-surfactant solutions as reaction media can be considered as an approach in this context because they show products with different features than those from isotropic solutions. Here we describe results obtained from studying the effect on the prototypical photoreaction, known as the photo-Fries reaction of several substituted acetanilides and α-naphthyl acetamide within surfactant micelles (ionic and non-ionic micelles). This reaction involves homolytic cleavage of a C-N bond to yield a singlet radical pair. The surfactant micelles control the rotational and translational mobility of the radical pair, resulting in noticeable photoproduct selectivity.
- Iguchi, Daniela,Erra-Balsells, Rosa,Bonesi, Sergio M.
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p. 105 - 116
(2016/01/20)
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- Synthesis of bridged benzazocines and benzoxocines by a titanium-catalyzed double-reductive umpolung strategy
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A sequence of two titanium(III)-catalyzed reductive umpolung reactions is reported that allows the rapid construction of benzazo- and benzoxozine building blocks. The first step is a reductive cross-coupling of quinolones or chromones with Michael acceptors. This reaction proceeds with complete syn-selectivity for the quinolone functionalization while the anti-diastereomers are obtained as the major products from chromones. With different reaction conditions, the stereochemical outcome can be altered to afford the syn-chromanone products as well. A subsequent reductive ketyl radical cyclization forges the tricyclic title compounds in good yields. A stereochemical model explaining the observed stereoselectivities is provided and the product configurations were unambiguously verified by X-ray analyses and 2D NMR spectroscopic experiments.
- Bichovski, Plamen,Haas, Thomas M.,Kratzert, Daniel,Streuff, Jan
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supporting information
p. 2339 - 2342
(2015/02/05)
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- Primary amino acid catalyzed asymmetric intramolecular Mannich reaction for the synthesis of 2-aryl-2,3-dihydro-4-quinolones
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Primary amino acids are found to be good enantioselective catalysts for the direct asymmetric Mannich reaction between 2-amino acetophenone and aldehydes. The 2-aryl-2,3-dihydro-4-quinoline products are obtained in moderate to good yields and good to high enantioselectivities with 10 mol% of the primary amino acid catalyst under mild reaction conditions.
- Mondal, Buddhadeb,Pan, Subhas Chandra
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supporting information
p. 9789 - 9792
(2015/01/09)
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- Br?nsted acid/rhodium(II) cooperative catalytic asymmetric three-component aldol-type reaction for the synthesis of 3-amino oxindoles
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Cooperation is key! Chiral Br?nsted acid/rhodium(II) cooperative catalysis enabled an enantioselective three-component aldol-type reaction of 3-diazo oxindoles and anilines with glyoxylates to give highly functionalized and structurally diverse 3-amino oxindoles in high stereoselectivity (>20:1 d.r., 99 % ee; see scheme). Copyright
- Ren, Lei,Lian, Xiao-Lei,Gong, Liu-Zhu
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supporting information
p. 3315 - 3318
(2013/07/11)
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- Ru(ii)-catalyzed intermolecular ortho-C-H amidation of aromatic ketones with sulfonyl azides
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Ru(ii)-catalyzed intermolecular ortho-C-H amidation of weakly coordinating aromatic ketones with sulfonyl azides is reported. The developed reaction protocol can be extended to various substituted aromatic ketones to afford a wide range of desired C-N bond formation products in good yields.
- Bhanuchandra,Ramu Yadav,Rit, Raja K.,Rao Kuram, Malleswara,Sahoo, Akhila K.
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supporting information
p. 5225 - 5227
(2013/06/27)
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- Selenium-promoted intramolecular oxidative amidation of 2-(arylamino)acetophenones for the synthesis of N-arylisatins
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A convenient method for the synthesis of N-arylisatins from 2-(arylamino)acetophenones by using SeO2 as an oxidant is described. Various substituted N-arylisatins were selectively obtained in good to excellent yields. The reaction tolerates a wide range of functionalities. Copyright
- Liu, Yong,Chen, Hui,Hu, Xiong,Zhou, Wang,Deng, Guo-Jun
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supporting information
p. 4229 - 4232
(2013/07/26)
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- Direct exchange of a ketone methyl or aryl group to another aryl group through ciC bond activation assisted by rhodium chelation
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Swapped: Commercially available quinolinone derivatives (1 or 2, see scheme) were reacted with arylboronic acids in the presence of a RhI complex to give aryl(quinolin-8-yl)methanone products 3 in medium to good yields. A mechanism that involves the in situ oxidation of RhI to RhIII by O2 in the presence of CuI was proposed. Copyright
- Wang, Jingjing,Chen, Weiqiang,Zuo, Sujing,Liu, Lu,Zhang, Xinrui,Wang, Jianhui
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supporting information
p. 12334 - 12338
(2013/02/23)
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- Synthesis of functionalized quinolines and benzo[c][2,7]naphthyridines based on a photo-fries rearrangement
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An efficient one-pot method for the synthesis of functionalized quinolines and tetrahydronaphthyridines has been developed. The photo-Fries rearrangement of p-substituted anilides afforded differently substituted o-amino ketones that reacted in situ with acetylenic Michael acceptors such as dimethyl acetylenedicarboxylate (DMAD) to give 6,4-disubstituted quinoline 2,3-dicarboxylates. Starting from anilides derived from β-alanine, a naphthyridine nucleus can also be assembled.
- Guerrini, Giacomo,Taddei, Maurizio,Ponticelli, Fabio
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experimental part
p. 7597 - 7601
(2011/11/12)
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- A general and efficient approach to 2H-indazoles and 1H-pyrazoles through copper-catalyzed intramolecular N-N bond formation under mild conditions
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A new efficient copper-catalyzed intramolecular amination reaction has been developed to readily synthesise a wide variety of multi-substituted 2H-indazole and 1H-pyrazole derivatives from easily accessible starting materials under mild conditions. A highly selective ligand for estrogen receptor β was prepared in three steps by employing this method. The Royal Society of Chemistry 2011.
- Hu, Jiantao,Cheng, Yongfeng,Yang, Yiqing,Rao, Yu
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supporting information; experimental part
p. 10133 - 10135
(2011/10/09)
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- Azaflavones compared to flavones as ligands to the benzodiazepine binding site of brain GABAA receptors
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A series of azaflavone derivatives and analogues were prepared and evaluated for their affinity to the benzodiazepine binding site of the GABAA receptor, and compared to their flavone counterparts. Three of the compounds, the azaflavones 9 and 12 as well as the new flavone 13, were also assayed on GABAA receptor subtypes (α1β3γ2s, α2β3γ2s, α4β3γ2s and α5β3γ2s), displaying nanomolar affinities as well as selectivity for α1- versus α2- and α3-containing receptors by a factor of between 14 and 26.
- Nilsson, Jakob,Nielsen, Elsebet stergaard,Liljefors, Tommy,Nielsen, Mogens,Sterner, Olov
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supporting information; experimental part
p. 5713 - 5716
(2009/08/07)
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- Thermal Fries rearrangement of anilides
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Anilides undergo thermal Fries rearrangement in the presence of TiCl4, ThCl4 and ZrOCl2 to afford either para-aminoaryl ketones exclusively or ortho- and para-aminoaryl ketones in which the para-product predominates.
- Ravi, Subban,Saravanan, Nagusamy,Shanthi, Andy,Dharmaraj, Nallusamy,Lakshmanan, Akoni J
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p. 443 - 445
(2007/10/02)
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- Optionally substituted 1,2,3,5-tetrahydroimidezo(2,1-b)-quinazolin-2-ones and 6(H)-1,2,3,4-tetrahydropyimido(2,1-b)quinazolin-2-ones
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Optionally substituted 1,2,3,5-tetrahydroimidazol[2,1-b]-quinazolin-2-ones and 6-[H]-1,2,3,4-tetrahydropyrimidol[2,1-b]quinazolin-2-ones or the pharmaceutically acceptable salts thereof are compounds useful as blood platelet anti-aggregative and/or antihypertensive and/or bronchodilator agents in mammals, including humans.
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- SURFACE PHOTOCHEMISTRY: THE AMIDE PHOTO-FRIES REARRANGEMENT
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The Photo-Fries rearrangement of eight anilides on the surface of dry silica gel has been examined.The rearrangement occurs quite cleanly, giving somewhat more of the para isomer than that obtained in methanolic solution.A test for intermolecularity on the silica gel surface showed that, as in solution, the radical pair intermediates do not separate.This contrasts with the behaviour of a previously reported dibenzyl ketone derivate.
- Magdy, M.,Malik, Abdel-,Mayo, Paul de
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p. 1275 - 1278
(2007/10/02)
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- Process for the preparation of optionally substituted 1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2-ones
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A new process has been developed for the synthesis of optionally substituted 1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2-ones. In particular, the process is particularly adaptable for the preparation of the 5,6-disubstituted compounds, e.g., 5,6-dimethyl-1,2,3,5-tetrahydroimidazo-[2,1-b]quinazolin-2-one. The compounds so prepared are useful as blood platelet anti-aggregative and/or antihypertensive agents in mammals, including humans.
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- Optionally substituted 1,2,3,5-tetrahydroimidezo(2,1-b)-quinazolin-2-ones and 6(H)-1,2,3,4-tetrahydropyimido(2,1-b)quinazolin-2-ones
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Optionally substituted 1,2,3,5-tetrahydroimidazo[2,1-b]-quinazolin-2-ones and 6-[H]-1,2,3,4-tetrahydropyrimido[2,1-b]-quinazolin-2-ones or the pharmaceutically acceptable salts thereof are compounds useful as blood platelet anti-aggregative and/or antihypertensive and/or bronchodilator agents in mammals, including humans.
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