- The intramolecular reaction of acetophenoneN-tosylhydrazone and vinyl: Br?nsted acid-promoted cationic cyclization toward polysubstituted indenes
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In the presence of TsNHNH2, a Br?nsted acid-promoted intramolecular cyclization ofo-(1-arylvinyl) acetophenone derivatives was developed, leading to polysubstituted indenes with complexity and diversity in moderate to excellent yields. In sharp contrast with either the radical or carbene involved cyclization of aldehydicN-tosylhydrazone with vinyl, a cationic cyclization pathway was involved, whereN-tosylhydrazone served as an electrophile and alkylation reagent during this transformation.
- Wang, Zhixin,Li, Yang,Chen, Fan,Qian, Peng-Cheng,Cheng, Jiang
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p. 1810 - 1813
(2021/02/27)
-
- Divergent Access to Benzocycles through Copper-Catalyzed Borylative Cyclizations
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A copper-catalyzed chemodivergent approach to five- and six-membered benzocycles from dienyl arenes tethered with a ketone has been developed. Through proper choice of coordinating ligands and catalytic conditions, copper-catalyzed borylative cyclization of a single dienyl arene can be diverted to two different pathways, leading to indanols and dihydronaphthalenols with high stereoselectivity. The chiral bidentate bisphosphine ligand (S,S)-Ph-BPE was optimal for asymmetric copper-allyl addition to a tethered ketone via a boat-like transition state, whereas NHC ligands led to boro-allyl addition producing indanols with high diastereoselectivity. (Figure presented.).
- Yoon, Wan Seok,Han, Jung Tae,Yun, Jaesook
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supporting information
p. 4953 - 4959
(2021/09/14)
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- Asymmetric Synthesis and Application of Chiral Spirosilabiindanes
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Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh-catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh-catalyzed hydrogenation and a Pd-catalyzed intramolecular carboamination.
- Chang, Xin,Chen, Hong-Chao,Li, Chuan-Ying,Ma, Pei-Long,Wang, Peng
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supporting information
p. 8937 - 8940
(2020/04/30)
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- Synthesis of Carbamates from Alkyl Bromides and Secondary Amines Using Silver Carbonate
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Synthesis of alkyl carbamates from alkyl bromides and secondary amines using silver carbonate as a carbonate source under mild condition is described. Various secondary amines and bromo derivatives were converted into alkyl carbamate derivatives in 33 to 62 % yield.
- Acharya, Vanitha,Mal, Sanjib,Kilaru, Jagadeesh P.,Montgomery, Mark G.,Deshpande, Sudhindra H.,Sonawane, Ravindra P.,Manjunath, Bhanu N.,Pal, Sitaram
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supporting information
p. 378 - 387
(2020/01/22)
-
- Synthesis of fluorenyl alcohols: Via cooperative palladium/norbornene catalysis
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Herein, we report a novel catalytic synthesis of substituted 9H-fluoren-9-ols starting from aryl iodides and secondary ortho-bromobenzyl alcohols in the presence of palladium/norbornene as a catalytic system. The present protocol exhibits high functional
- Casnati, Alessandra,Fontana, Marco,Motti, Elena,Della Ca, Nicola
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p. 6165 - 6173
(2019/07/04)
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- NBS-mediated synthesis of β-keto sulfones from benzyl alcohols and sodium arenesulfinates
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An efficient synthetic route towards the synthesis of β-keto sulfones has been developed from secondary benzyl alcohols using N-bromosuccinimide (NBS). The present protocol utilizes NBS as oxidant as well as brominating agent, readily accessible benzyl alcohols and sodium arenesulfinates as the sulfonylating reagent under mild conditions. The control experiments revealed that the reaction proceeds via oxidation of alcohol to ketone, α-bromination of ketone and nucleophilic substitution by sodium arenesulfinate. Furthermore, the efficiency of the methodology was tested with a gram scale reaction and also shown the synthetic utility.
- Muneeswara, Madithedu,Sundaravelu, Nallappan,Sekar, Govindasamy
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supporting information
p. 3479 - 3484
(2019/05/21)
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- Phosphine- and water-promoted pentannulative aldol reaction
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Herein, an efficient metal-free intramolecular aldol reaction for the synthesis of an unusual class of cyclopentanoids is described. The reaction of α-substituted dienones tethered with ketones in the presence of tributylphosphine and water provided aldols. The role of water was realised to be crucial for this transformation. Furthermore, isotopic labeling experiments provided vital information about the reaction mechanism.
- Satpathi, Bishnupada,Dutta, Lona,Ramasastry
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supporting information
p. 1547 - 1551
(2019/02/14)
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- Fe-Catalyzed Cycloisomerization of Aryl Allenyl Ketones: Access to 3-Arylidene-indan-1-ones
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A cycloisomerization of aryl allenyl ketones to 3-arylidene-indan-1-ones using a cationic Fe-complex as a catalyst is reported. The catalyst opens a synthetically interesting reaction pathway to this surprisingly underrepresented class of indanones that are not accessible using alternative catalytic systems.
- Teske, Johannes,Plietker, Bernd
-
supporting information
p. 2257 - 2260
(2018/04/27)
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- One-Pot Asymmetric Synthesis of Alkylidene 1-Alkylindan-1-ols Using Br?nsted Acid and Palladium Catalysis
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A one-pot catalytic enantioselective allylboration/Mizoroki-Heck reaction of 2-bromoaryl ketones has been developed for the asymmetric synthesis of 3-methyleneindanes bearing a tertiary alcohol center. Br?nsted acid-catalyzed allylboration with a chiral BINOL derivative was followed by a palladium-catalyzed Mizoroki-Heck cyclization, resulting in selective formation of the exo-alkene. This novel protocol provides a concise and scalable approach to 1-alkyl-3-methyleneindan-1-ols in high enantiomeric ratios (up to 96:4 er). The potential of these compounds as chiral building blocks was demonstrated with efficient transformation to optically active diol and amino alcohol scaffolds.
- Faggyas, Réka J.,Calder, Ewen D. D.,Wilson, Claire,Sutherland, Andrew
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p. 11585 - 11593
(2017/11/10)
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- Stereoselective Ketone Rearrangements with Hypervalent Iodine Reagents
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The first stereoselective version of an iodine(III)-mediated rearrangement of arylketones in the presence of orthoesters is described. The reaction products, α-arylated esters, are very useful intermediates in the synthesis of bioactive compounds such as ibuprofen. With chiral lactic acid-based iodine(III) reagents product selectivities of up to 73 % ee have been achieved.
- Malmedy, Florence,Wirth, Thomas
-
supporting information
p. 16072 - 16077
(2016/10/30)
-
- Diisobutylaluminum hydride-promoted cyclization of benzyl and phenylsilyl ethers bearing a 2-(trimethylsilyl)ethynyl group: syntheses of indenes and benzosiloles
-
The reaction of o-[2-(trimethylsilyl)ethynyl]benzyl methyl ethers with diisobutylaluminum hydride (DIBAL-H) gave 2-(trimethylsilyl)indenes in good yields. This cyclization proceeds by regio- and stereoselective hydroalumination of the alkyne moiety followed by intramolecular nucleophilic substitution. o-[2-(Trimethylsilyl)ethynyl]phenylsilyl methyl ethers also underwent the DIBAL-H promoted-cyclization to be converted into 2-(trimethylsilyl)benzosiloles in good yields. This approach provides straightforward and efficient way to construct benzosiloles from readily available organosilanes.
- Kinoshita, Hidenori,Fukumoto, Hiroki,Tohjima, Takayuki,Miura, Katsukiyo
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supporting information
p. 3571 - 3574
(2016/07/18)
-
- Borylation of Olefin C-H Bond via Aryl to Vinyl Palladium 1,4-Migration
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The aryl to vinyl palladium 1,4-migration was realized for the first time. The generated alkenyl palladium species was trapped by diboron reagents under Miyaura borylation conditions, providing a new method to synthesize β,β-disubstituted vinylboronates. The excellent regioselectivity and broad substrate scope were observed for this novel transformation.
- Hu, Tian-Jiao,Zhang, Ge,Chen, Ya-Heng,Feng, Chen-Guo,Lin, Guo-Qiang
-
supporting information
p. 2897 - 2900
(2016/03/19)
-
- Cu-MEDIATED ANNULATION FOR THE EFFECTIVE SYNTHESIS OF 3-SUBSTITUTED PHTHALIDES
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The present invention disclosed herein is a novel commercially feasible, one pot synthesis of library of 3-substituted phthalides of formula I via CuCN mediated oxidative cyclization in high yield. Formula I
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-
Page/Page column 0081; 0082; 0091
(2015/02/25)
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- Synthesis of 1-indanols and 1-indanamines by intramolecular palladium(0)-catalyzed C(sp3)-H arylation: Impact of conformational effects
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A range of valuable 1-indanols and 1-indanamines containing a tertiary C1 atom were synthesized by intramolecular palladium(0)-catalyzed C(sp 3)-H arylation, despite unfavorable steric interactions. The efficiency of the reaction was found to correlate with the degree of substitution at C2, as expected from the Thorpe-Ingold effect. Additionally, the nature of the heteroatomic substituent at C1 had a marked influence on the diastereoselectivity at C1 and C2; indeed, 1-indanols and 1-indanamines were obtained with the opposite relative configuration. Analysis of the X-ray and DFT-optimized structures of the corresponding reactive intermediates provided useful insights into the subtle conformational effects induced by these substituents.
- Janody, Simon,Jazzar, Rodolphe,Comte, Arnaud,Holstein, Philipp M.,Baudoin, Olivier,Vors, Jean-Pierre,Ford, Mark J.
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p. 11084 - 11090,7
(2014/10/15)
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- Cu-MEDIATED ANNULATION FOR THE EFFECTIVE SYNTHESIS OF 3-SUBSTITUTED PHTHALIDES
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The present invention disclosed herein is a novel commercially feasible, one pot synthesis of library of 3-substituted phthalides of formula I via CuCN mediated oxidative cyclization in high yield. Formula I
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-
Page/Page column 15
(2013/07/19)
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- New bifunctional organocatalysts based on (R,R)-cyclohexane-1,2-diamine for the asymmetric addition of nucleophiles to aldehydes
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The amide and sulfamide derivatives of (1R,2R)-N,N-diethylcyclohexane-1,2- diamine can serve as organocatalysts for addition of Me3SiCN and Et2Zn to aldehydes.
- Maleev,Gugkaeva,Tsaloev,Moskalenko,Khrustalev
-
-
- A domino palladium-catalyzed C-C and C-O bonds formation via dual O-H bond activation: Synthesis of 6,6-dialkyl-6 H -benzo[ c ]chromenes
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An efficient Pd-catalyzed domino reaction of α,α-dialkyl-(2- bromoaryl)methanols to 6,6-dialkyl-6H-benzo[c]chromenes is presented. Their formation can be explained via a five membered Pd(II)-cycle that efficiently involves a domino homocoupling with the second molecule, β-carbon cleavage, and finally intramolecular Buchwald-Hartwig cyclization. This domino process effectively involves breaking of five σ-bonds (2C-Br, 2O-H, and a C-C) and formation of two new σ-bonds (C-C and C-O). This mechanistic pathway is unprecedented and further illustrates the power of transition metal catalysis.
- Mahendar, Lodi,Krishna, Jonnada,Gopi Krishna Reddy, Alavala,Venkat Ramulu, Bokka,Satyanarayana, Gedu
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supporting information; experimental part
p. 628 - 631
(2012/03/11)
-
- Synthesis and structural features of chiral cyclic squaramides and their application in asymmetric catalytic reaction
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We report the synthesis and structural elucidation of two series of chiral cyclic squaramides, i.e. six-and twelve-membered ring squaramides 4 and 6, based on the cyclobutenedione structure, containing enantiomerically pure (1R,2R)-1,2-diphenylethylenediamine as the chiral element. Compounds 4a-d obtained from alkylation of 3, crystallize in space groups of monoclinic P2 1, monoclinic P21, monoclinic chiral P212 121, and the orthorhombic C2221, respectively. For the first time the crystal structures of six-membered ring chiral cyclic squaramides are reported. These novel ligands have been tested in the enantioselective addition of diethylzinc to aryl aldehydes to give the corresponding alcohols in moderate yields, albeit with low enantioselectivity. ARKAT-USA, Inc.
- Jin, Xiaoqing,Min, Qiaoqiao,Zheng, Yangfan,Wang, Pengcheng,Zhu, Jun,Zhou, Hai-Bing
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experimental part
p. 322 - 335
(2011/03/17)
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- Iron-catalyzed, microwave-promoted, one-pot synthesis of 9-substituted xanthenes by a cascade benzylation-cyclization process
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"Chemical Equation Presented" An efficient iron-catalyzed, microwave-promoted cascade benzylation-cyclization of phenols is reported. Benzyl acetates, benzyl bromides, and benzyl carbonates are suitable benzylating reagents. The reactions proceed to afford both 9-aryl and 9-alkyl xanthene derivatives in good to high yields using FeCI3 as the catalyst under MW irradiation conditions
- Xu, Xiaobing,Xu, Xiaolei,Li, Hongfeng,Xie, Xin,Li, Yanzhong
-
supporting information; experimental part
p. 100 - 103
(2010/03/04)
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- Convenient synthesis of a new class of chiral hydroxymethyl-dihydrooxazole ligands and their application in asymmetric addition of diethylzinc to aromatic aldehydes
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A number of chiral hydroxymethyl-substituted dihydrooxazoles were synthesized from D- or L-mandelic acid and amino alcohols. The chiral ligands thus obtained were tested as catalyst in the asymmetric addition of diethylzinc to aromatic aldehydes, and the
- Li, Zhi-Ting,Li, Xin-Sheng,Li, Liang-Chao,Xu, Dong-Cheng
-
p. 545 - 549
(2007/10/03)
-
- Enantioselective C-C bond cleavage creating chiral quaternary carbon centers
-
A chiral all-carbon benzylic quaternary carbon center is created by the asymmetric intramolecular addition/ring-opening reaction of a boryl-substituted cyclobutanone, which involves enantioselective β-carbon elimination from a symmetrical rhodium cyclobutanolate. The asymmetric reaction was successfully applied to a synthesis of sesquiterpene, (-)-α-herbertenol.
- Matsuda, Takanori,Shigeno, Masanori,Makino, Masaomi,Murakami, Masahiro
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p. 3379 - 3381
(2007/10/03)
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- Remote stereocontrol by sulfinyl groups: Asymmetric alkylation of chiral 2-p-tolylsulfinyl benzyl carbanions
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Alkylation reactions of the benzyllithiums derived from enantiomerically pure 2-p-tolylsulfinyl alkylbenzenes have been carried out with excellent yields and high de. A lithiation-substitution sequence, stereochemically controlled by a remote sulfoxide, accounts for the experimental results.
- García Ruano, José L.,Aranda, M. Teresa,Puente, Margarita
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p. 10099 - 10104
(2007/10/03)
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- SULFONYLPHENYLPYRAZOLE COMPOUNDS USEFUL AS COX-2 INHIBITORS
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The present invention encompasses novel sulfonylphenylpyrazole compounds useful in the treatment of cyclooxygenase-2 mediated diseases.
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-
- Synthesis of 4,5-Diaryl-1H-pyrazole-3-ol derivatives as potential COX-2 inhibitors
-
4,5-Diaryl-1H-pyrazole-3-ol was utilized as a versatile template to synthesize several classes of compounds such as pyrazolo-oxazines 7, pyrazolo-benzooxazines 9, pyrazolo-oxazoles 10, and its analogues 11a-c as potential COX-2 inhibitors. Compounds 11b,c were successfully synthesized with use of pyridinium p-toluenesulfonate mediated cyclization of the ketal intermediate. Diarylpyrazolo-benzooxazepine analogues were synthesized by using Cu-mediated cyclization of the O-alkylated arylbromide intermediate. Arylsulfonamides were synthesized efficiently on a large scale with 4-[4-(4-fluorophenyl)-5-hydroxy-2H-pyrazol-3-yl]benzenesulfonamide 31 template readily synthesized from commercially available 4-sulfamoyl benzoic acid 29. The structure of a representative compound from each class was confirmed by X-ray crystallography. Selected compounds tested for inhibitory activity against COX-1 and COX-2 enzymes showed good selectivity for COX-2 versus COX-1 enzyme.
- Patel, Meena V.,Bell, Randy,Majest, Sandra,Henry, Rodger,Kolasa, Teodozyj
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p. 7058 - 7065
(2007/10/03)
-
- First detection of a selenenyl fluoride ArSe-F by NMR spectroscopy: The nature of Ar2Se2/XeF2 and ArSe-SiMe 3/XeF2 reagents
-
Arylselenenyl fluorides ArSeF are obtained from diselenides Ar 2Se2 or arylselenotrimethylsilanes ArSe-SiMe3, and XeF2. They are detected by low-temperature 19F and 77Se NMR spectroscopy. Substitution in the ortho position of the aromatic ring to provide electronic or steric protection is a requirement for their formation. ArSe-F compounds decompose according to 3 ArSe-F → [ArSe-SeF2Ar] + ArSe-F- → ArSeF3 + Ar 2Se2. Reaction energies for this disproportionation as well as that of the sulfur and tellurium homologues have been calculated with MP2, CCSD(T,) and B3 LYP methods. They were found to be increasingly exothermic in the sequence S 77Se and 19F chemical shifts have been calculated by GIAO-MP2 and GIAO-B3LYP methods and are in good agreement with experimental values.
- Poleschner, Helmut,Seppelt, Konrad
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p. 6565 - 6574
(2007/10/03)
-
- 2-piperidone compounds
-
The present invention provides 2-piperidone compounds or pharmaceutically acceptable salts thereof, which have a potent activity of inhibiting the proliferation of tumor cells and thus are useful as medicaments, as well as antitumor agents containing thes
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-
-
- Sulfonylphenylpyrazole compounds useful as COX-2 inhibitors
-
The present invention encompasses novel sulfonylphenylpyrazole compounds useful in the treatment of cyclooxygenase-2 mediated diseases.
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-
-
- Synthesis and activity of 2-methyl-3-aminopropiophenones as centrally acting muscle relaxants
-
Some novel 2-methyl-3-aminopropiophenones were synthesized and their centrally acting muscle relaxant activities were,evaluated for an inhibitory effect on the flexor reflex in rats. The structure-activity relationships are discussed. In this series 2-methyl-3-pyrrolidino-1-(4-trifluoromethylphenyl)-propan-1-one (28) showed significant centrally acting muscle relaxant activity. In addition, the activities of each enantiomer (28-(S) and (R)) were studied along with their acute toxicities. Compound 28-(R) was found to exhibit more potent activity and weaker acute toxicity than 28-(S). Accordingly, compound 28-(R) (NK433) is under development as a novel centrally acting muscle relaxant.
- Shiozawa,Narita,Izumi,Kurashige,Sakitama,Ishikawa
-
-
- Oxygenated phenanthrenes via quinol ketals: Cyclization vs. migration
-
2-methoxyphenanthrenes were prepared by reaction of lithiated 2-bromostyrenes with quinone monoketals followed by acid-mediated cyclization of the resulting p-arylquinol ketals. Substitution at the bromostyrene side-chain or the quinone monoketal ring had only a modest effect on yields, but oxygen substitution on the bromostyrene aromatic nucleus resulted in a competing 1,2-aryl migration arising during the quinol ketal cyclization step. The extent of this rearrangement was found to be a function of the Lewis acid/solvent system employed.
- Morrow, Gary W.,Marks, Tina M.,Sear, Debra L.
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p. 10115 - 10124
(2007/10/02)
-
- Catalytic Enantioselective Synthesis of Optically Active Phthalides
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Optically active phthalides of high enantiomeric excesses (86-90percent e.e.) were synthesized from the addition of dialkylzincs to 2-bromobenzaldehyde using N,N-dibutylnorephedrine as a chiral catalyst.
- Soai, Kenso,Hori, Hiroshi,Kawahara, Masato
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p. 253 - 254
(2007/10/02)
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- INTRAMOLECULAR CYCLIZATION OF 2'-OLEFINIC SIDE-CHAINS ON ANODICALLY OXIDIZED 4-PHENYLPHENOLS. THE EFFECT OF OLEFIN SUBSTITUENTS ON CARBON-CARBON BOND FORMATION
-
The anodic oxidation of 4-(2'-alkenylphenyl)phenols in acetonitrile/methanol affords spirodienones arising from cyclization of the olefinic side-chain to the 4-position of the phenol and reaction of the resulting benzylic cation with methanol.The efficiency of this carbon-carbon bond-forming reaction is dependent upon the olefinic substituents.
- Morrow, Gary W.,Chen, Ying,Swenton, John S.
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p. 655 - 664
(2007/10/02)
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- Inverse Electron Demand Diels-Alder Reactions of Heterocyclic Aza Dienes. Studies on the Total Synthesis of Lavendamycin: Investigative Studies on the Preparation of the CDE β-Carboline Ring System and AB Quinoline-5,8-quinone Ring System
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The investigation and utilization of the inverse electron demand cycloaddition of 3,5,6-tris(ethoxycarbonyl)-1,2,4-triazine with electron-rich olefins and the subsequent implementation of a palladium(0)-mediated β-carboline synthesis for the preparation of the CDE ring system of lavendamycin are detailed.Studies on the introduction and preparation of the 7-aminoquinoline-5,8-quinone AB ring system of lavendamycin are described.
- Boger, Dale L.,Duff, Steven R.,Panek, James S.,Yasuda, Masami
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p. 5782 - 5789
(2007/10/02)
-
- Studies Dealing with the Intramolecular Ene Reaction of Cyclopropene Derivatives
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The thermal and triplet-sensitized behavior of a series of 3-(o-alkenylphenyl)-substituted cyclopropenes has been studied.The results obtained indicate that the course of the thermolysis depends on the substituent groups present on the double bond.Thermolysis of the trans-substituted 3-(o-1-propenylphenyl)cyclopropene gives rise to a 2 + 2 cycloadduct.In marked contrast, heating a sample of the cis isomer results in a concerted ene reaction.The geometry for this type of reaction is easily achieved with the Z isomer.The triplet-sensitized reaction of these systems produced a 3:1 mixture of the 2 + 2 cycloadduct as well as the ene product.A related ene reaction was also observed with the 3-(o-(2-methyl-1-propenyl)-phenyl)-substituted cyclopropene.The primary deuterium isotope was determined (kH/kD = 3.5) and was found to be consistent with a concerted transition state where the hydrogen transfer is nonlinear.No significant isotope effect was encountered in the sensitized irradiation.The regiospecificity associated with the thermal and triplet-sensitized ene reaction of an unsymmetrically substituted cyclopropene was also studied.The regiochemistry encountered in the sensitized irradiation is attributed to ?-? bridging to give the most stable diradical intermediate.Frontier MO theory provides a nice rationalization for the regiochemistry in the thermal reaction.
- Padwa, Albert,Rieker, William F.,Rosenthal, Robert J.
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p. 1710 - 1717
(2007/10/02)
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- PALLADIUM (0) MEDIATED β-CARBOLINE SYNTHESIS: PREPARATION OF THE CDE RING SYSTEM OF LAVENDAMYCIN
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A five-step approach to the preparation of the β-carboline CDE ring system of lavendamycin is detailed and is based on: (1) thermal cycloaddition of 3,5,6-tricarbomethoxy-1,2,4-triazine with the pyrrolidine enamine of o-bromopropiophenone followed by (2) implementation of a newly developed palladium (0) mediated β-carboline synthesis.
- Boger, Dale L.,Panek, James S.
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p. 3175 - 3178
(2007/10/02)
-
- Iminyls. Part 9. Intramolecular Addition of an Iminyl to an Alkene
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Phenyl o-styrylphenyl iminyl, generated by oxidation of the corresponding O-carboxymethyloxime with persulphate and by thermolysis of the perester of that acid, cyclises to give a mixture of isoquinoline and 1H-isoindole derivatives.The intermediate radicals have been investigated by e.s.r.
- Atmaram, Shiravante,Forrester, Alexander R.,Gill, Melvin,Thomson, Ronald H.
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p. 1721 - 1724
(2007/10/02)
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