- 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)
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- 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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p. 4953 - 4959
(2021/09/14)
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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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p. 378 - 387
(2020/01/22)
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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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p. 8937 - 8940
(2020/04/30)
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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
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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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- Enantioselective Bromo-oxycyclization of Silanol
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Relying on the nucleophilicity of silanol for building up silicon-incorporated scaffold with an enantiopure tetrasubstituted carbon center remains elusive. In this report, asymmetric bromo-oxycyclization of olefinic silanol by using chiral anionic phase-transfer catalyst is described. This protocol provided a facile entry to a wide arrangement of enantiopure benzoxasilole in moderate to excellent enantioselectivities depending on the unique reactivity of bromine/N-benzyl-DABCO complex.
- Xia, Zilei,Hu, Jiadong,Shen, Zhigao,Wan, Xiaolong,Yao, Qizheng,Lai, Yisheng,Gao, Jin-Ming,Xie, Weiqing
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supporting information
p. 80 - 83
(2016/01/15)
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- 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
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p. 2897 - 2900
(2016/03/19)
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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
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p. 16072 - 16077
(2016/10/30)
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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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supporting information
p. 11084 - 11090,7
(2014/10/15)
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- 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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p. 628 - 631
(2012/03/11)
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- Enantioselective C-C bond cleavage creating chiral quaternary carbon centers
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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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- THERAPEUTIC AGENT FOR DIABETES
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A therapeutic agent for diabetes, which comprises a compound of the formula [I] wherein Xis a group of the formula wherein R4and R5are the same or different and each is a hydrogen atom, an optionally substituted alkyl having 1 to 5 carbon atoms and the like, and R6is a hydrogen atom or an amino-protecting group; R1is an optionally substituted alkyl having 1 to 5 carbon atoms, an optionally substituted alkenyl having 2 to 6 carbon atoms and the like, R2is a hydrogen atom, an optionally substituted alkyl having 1 to 5 carbon atoms and the like, R2' is a hydrogen atom, and R3is an optionally substituted alkyl having 1 to 5 carbon atoms and the like, a prodrug thereof, a pharmaceutically acceptable salt thereof, a hydrate thereof and a solvate thereof. The compound of the present invention shows superior blood sugar decreasing action on the state of hyperglycemia, but does not affect the blood sugar when it is in the normal range or in the hypoglycemic state, which means that it is free of serious side effects such as hypoglycemia. Therefore, the compound of the present invention is useful as a therapeutic drug for diabetes and also useful as a preventive of the chronic complications of diabetes.
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- Synthesis and activity of 2-methyl-3-aminopropiophenones as centrally acting muscle relaxants
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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
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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
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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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- Spiro-Fused 2,5-Cyclohexadienones from the Thermal 1,3-Alkyl Migrations of Quinol Vinyl Ethers. A Strategy for Conversion of a Carbonyl Carbon to a Quaternary Carbon
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Reaction of p-benzoquinone monoketals with 2-lithio derivatives of acetophenone and propiophenone dimethyl ketals results in organolithium addition to the carbonyl group of the quinone monoketal to afford the ketals of 4-aryl-4-hydroxy-1,5-cyclohexadienones.Reaction of these products with aqueous acid results in hydrolysis of 2,5-cyclohexadienone ketal and intramolecular mixed ketal formation between 4-hydroxyl group and the 2-substituted acetyl or propionyl side chain of the aromatic ring.Conversion of this cyclic ketal to the vinyl ether by loss of methanol affords the quinol ether derivatives for thermolysis.Variants of this chemistry were used to prepare a number of spiro-fused vinyl ethers of the p-quinols.At 130-170 deg C these molecules undergo high-yield conversion of the vinyl ether moiety to a ketone, affording spiro-fused 4,4-disubstituted 2,5-cyclohexadienones.Rates have been measured for several of these formal -shifts, and a ρ value of -0.87 was calculated for rearrangement of compounds having aryl substituents on the vinyl ether double bond.This chemistry establishes a high-yield strategy for conversion of p-benzoquinone monoketals, 4,4-dialkoxy-2,5-cyclohexadienones, to spiro-fused 2,5-cyclohexadienones.
- Wang, Shaopeng,Morrow, Gary W.,Swenton, John S.
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p. 5364 - 5371
(2007/10/02)
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- Therapeutically useful 1-phenyl-2-piperidinoalkanol derivatives
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Compounds of the formula: STR1 wherein R1 is hydrogen, halogen, trifluoromethyl, alkyl, hydroxyl, alkyoxy, benzyloxy, alkanoyloxy, or benzoyloxy, or when R2 is hydroxyl or methoxy in the 4-position and R3 is hydrogen, R1 may also represent hydroxymethyl carbamoyl or alkoxycarbonyl, R2 is hydrogen, halogen, alkyl, hydroxyl, or alkoxy, R3 is hydrogen or alkyl, R4 is alkyl (in which case the compounds are (±)-erythro) or when R3 represents hydrogen, R4 may also be hydrogen, and R5 is hydrogen, halogen, alkyl, alkoxy, or three methoxy groups in the 3-, 4- and 5-positions and pharmaceutically acceptable acid addition salts thereof, with the exclusion of compounds wherein: (a) one of R1 and R2 is in the 4-position and is hydroxyl, alkoxy or benzyloxy, the other is in the 3-position and is hydrogen, hydroxyl, alkoxy or benzyloxy, and R3 and R5 are hydrogen and wherein: (b) R1 is in the 4-position and is halogen, R4 is methyl and R2, R3 and R5 are hydrogen, are useful as medicaments.
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- Fungicidal hydroxyalkinyl-azolyl derivatives
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Hydroxyalkinyl-azolyl derivatives of the formula STR1 in which A is a nitrogen atom or the CH group, R is optionally substituted alkyl, cycloalkyl or phenyl, R1 is hydrogen, alkyl, alkenyl, alkinyl, or optionally substituted benzyl, R2 is hydrogen or methyl, and X is hydrogen, bromine or iodine, or addition products thereof with acids or metal salts exhibit fungicidal activity. Some intermediates therefor are also new.
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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)
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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)
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