- Chiral Magnesium Bisphosphate-Catalyzed Asymmetric Double C(sp3)-H Bond Functionalization Based on Sequential Hydride Shift/Cyclization Process
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Described herein is a chiral magnesium bisphosphate-catalyzed asymmetric double C(sp3)-H bond functionalization triggered by a sequential hydride shift/cyclization process. This reaction consists of stereoselective domino C(sp3)-H bond functionalization: (1) a highly enantio- and diastereoselective C(sp3)-H bond functionalization by chiral magnesium bisphosphate (first [1,5]-hydride shift), and (2) a highly diastereoselective C(sp3)-H bond functionalization by an achiral catalyst (Yb(OTf)3, second [1,5]-hydride shift).
- Mori, Keiji,Isogai, Ryo,Kamei, Yuto,Yamanaka, Masahiro,Akiyama, Takahiko
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supporting information
p. 6203 - 6207
(2018/05/23)
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- Construction of 1,3-Dithio-Substituted Tetralins by [1,5]-Alkylthio Group Transfer Mediated Skeletal Rearrangement
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A novel skeletal rearrangement involving a [1,5]-alkylthio group transfer/cyclization sequence is described. Treatment of benzylidene malonates having a thioketal moiety at the homobenzyl position with a catalytic amount of Sc(OTf)3 afforded alkylthio group rearranged adducts in good chemical yields. Detailed investigation of the reaction mechanism revealed that an intramolecular conjugate addition/ring opening sequence (not through-space transfer) is the key to achieving this reaction.
- Hisano, Naoya,Kamei, Yuto,Kansaku, Yaoki,Yamanaka, Masahiro,Mori, Keiji
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supporting information
p. 4223 - 4226
(2018/07/29)
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- Highly diastereoselective synthesis of tetralin-fused spirooxindoles via lewis acid-catalyzed C(sp3)H bond functionalization
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A highly diastereoselective synthesis of tetralin-fused spirooxindole derivatives was described. Treatment of benzylidene oxindoles with a catalytic amount of Sc(OTf)3 in refluxing hexane afforded the target compounds in good chemical yields with excellent diastereoselectivities (up to >20:1). Detailed investigation of the reaction mechanism revealed that both interconversion of the two diastereomers and their solubility difference in reaction medium were the key to achieving excellent diastereoselectivities.
- Machida, Mizuki,Mori, Keiji
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supporting information
p. 868 - 871
(2018/07/03)
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- Gold-catalyzed 1,2-oxoarylations of nitriles with pyridine-derived oxides
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We report the first success in the gold-catalyzed oxoarylations of nitriles with pyridine-derived N-oxides using gold carbenes as initiators. These oxoarylations were also achieved satisfactorily in intermolecular three-component oxidations, including diverse alkenyldiazo esters, nitriles, and pyridine-based oxides. Spill the (car)benes: Reported herein is the first successful gold-catalyzed oxoarylation of nitriles with pyridine-derived N-oxides using gold carbenes as initiators (see scheme; DCE=1,2-dichloroethane, IPr=1,3-bis(diisopropylphenyl)imidazol-2-ylidene). These oxoarylations were also achieved satisfactorily in intermolecular three-component oxidations using a variety of alkenyldiazo esters, nitriles, and pyridine-based N-oxides.
- Karad, Somnath Narayan,Liu, Rai-Shung
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supporting information
p. 5444 - 5448
(2014/06/09)
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- Copper-catalyzed domino coupling reaction: An efficient method to synthesize oxindoles
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An efficient and novel procedure for a copper catalyzed domino coupling reaction has been developed, which afforded various oxindoles in good to excellent yields with tolerance of various substituents. In addition, this method could be applied to synthesize horsfiline and coerulescine in few steps with high total yields. The Royal Society of Chemistry 2012.
- Hsieh, Jen-Chieh,Cheng, An-Yi,Fu, Jun-Hao,Kang, Ting-Wei
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supporting information; experimental part
p. 6404 - 6409
(2012/09/05)
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- Diastereo- and enantioselective intramolecular C(sp3)-H arylation for the synthesis of fused cyclopentanes
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All C-H bonds are not equal: The intramolecular arylation of unactivated C(sp3)-H bonds in the presence of a chiral Pd/binepine catalyst allows the synthesis of fused cyclopentanes efficiently and in an diastereo- and enantioselective manner (see scheme).
- Martin, Nicolas,Pierre, Cathleen,Davi, Micha?l,Jazzar, Rodolphe,Baudoin, Olivier
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supporting information; experimental part
p. 4480 - 4484
(2012/05/20)
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- Synthesis and pharmacological evaluation of 1-isopropyl-1,2,3,4- tetrahydroisoquinoline derivatives as novel antihypertensive agents
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A series of 1-isopropyl-1,2,3,4-tetrahydroisoquinoline derivatives were synthesized and their bradycardic activities were evaluated in isolated guinea pig right atria. Structure-activity relationship studies revealed that the introduction of an appropriate substituent and its position on the 1,2,3,4-tetrahydroisoquinoline ring are essential for potent in vitro activity. Furthermore, the tether between the piperidyl moiety and the terminal aromatic ring is important for potent antihypertensive activity. Oral administration of 6-fluoro-1-isopropyl-2-{[1-(2-phenylethyl)piperidin-4-yl]carbonyl}-1,2,3, 4-tetrahydroisoquinoline (3b) to spontaneously hypertensive rats (SHR) elicited antihypertensive effects without inducing reflex tachycardia, which is often caused by traditional L-type Ca2+ channel blockers.
- Watanuki, Susumu,Matsuura, Keisuke,Tomura, Yuichi,Okada, Minoru,Okazaki, Toshio,Ohta, Mitsuaki,Tsukamoto, Shin-Ichi
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experimental part
p. 1029 - 1037
(2011/10/18)
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- Synthesis of N-alkoxyindol-2-ones by copper-catalyzed intramolecular N-arylation of hydroxamates
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The first example of copper-catalyzed intramolecular N-arylation of hydroxamic acid derivatives is presented. Based on this transformation a new method for the synthesis of N-alkoxyindol-2-ones from 2-(2-bromoaryl) acetylhydroxamates has been developed. T
- Kukosha, Tatyana,Trufilkina, Nadezhda,Katkevics, Martins
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p. 2525 - 2528
(2011/11/13)
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- CYCLIC DIARYL ETHER COMPOUNDS AS ANTAGONISTS OF PROSTAGLANDIN D2 RECEPTORS
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Described herein are compounds that are antagonists of PGD2 receptors. Also described are pharmaceutical compositions and medicaments that include the antagonists of PGD2 receptors described herein, as well as methods of using such antagonists of PGD2 receptors, alone and in combination with other compounds, for treating respiratory, cardiovascular, and other PGD2-dependent or PGD2-mediated conditions or diseases.
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Page/Page column 112
(2009/10/09)
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- Synthesis of benzocyclobutenes by palladium-catalyzed C-H activation of methyl groups: Method and mechanistic study
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An efficient catalytic system has been developed for the synthesis of benzocyclobutenes by C-H activation of methyl groups. The optimal conditions employed a combination of Pd(OAc)2 and PtBu3 as catalyst, K2CO3 as the base, and DMF as solvent. A variety of substituted BCB were obtained under these conditions with yields in the 44-92% range, including molecules that are hardly accessible by other methods. The reaction was found limited to substrates bearing a quaternary benzylic carbon, but benzocyclobutenes bearing a tertiary benzylic carbon could be obtained indirectly from diesters by decarboxylation. Reaction substrates bearing a small substituent para to bromine gave an unexpected regioisomer that likely arose from a 1,4-palladium migration process. The formation of this "abnormal" regioisomer could be suppressed by introducing a larger subsituent para to bromine. DFT(B3PW91) calculations on the reaction of 2-bromo-tert-butylbenzene with Pd(PtBu3) with different bases (acetate, bicarbonate, carbonate) showed the critical influence of the coordination mode of the base to induce both an easy C-H activation and to allow for a pathway for 1,4-palladium migration. Carbonate is shown to be more efficient than the two other bases because it can abstract the proton easily and at the same time maintain κ1-coordination without extensive electronic reorganization.
- Chaumontet, Manon,Piccardi, Riccardo,Audic, Nicolas,Hitce, Julien,Peglion, Jean-Louis,Clot, Eric,Baudoin, Olivier
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supporting information; experimental part
p. 15157 - 15166
(2009/03/12)
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- Synthetic study of hetisine-type aconite alkaloids. Part 1: Preparation of tetracyclic intermediate containing the C14-C20 bond
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Full details for the total synthesis of (±)-nominine, a hetisine-type aconite alkaloid, are presented in three parts. Here (part 1), we describe the preparation of the key tetracyclic intermediate 6. Our palladium-catalyzed intramolecular α-arylation was adopted for preparation of the intermediate 4 with an angular formyl group. An acetal-ene reaction was then employed for C14-C20 bond formation to secure 6 from 5. The reaction mechanism of the acetal-ene reaction is discussed, and a method for removal of the 2-hydroxyethyl group from 6 is developed.
- Muratake, Hideaki,Natsume, Mitsutaka
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p. 7056 - 7070
(2007/10/03)
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- SUBSTITUTED AMINO PHENYLACETIC ACIDS, DERIVATIVES THEREOF, THEIR PREPARATION AND THEIR USE AS CYCLOOXYGENASE 2 (COX-2) INHIBITORS
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Compounds of formula (I) wherein R is hydrogen, lower alkyl, (C3-C8)cycloalkyl, hydroxy, halo, lower alkoxy, trifluoromethoxy, trifluoromethyl or cyano; and A is biaryl, optionally substituted β-naphthyl, bicyclic heterocyclic aryl, (C3-C6)cycloalkylmonocyclic carbocyclic aryl, or (C5 or C6)cycloalkane fused-monocyclic carbocyclic aryl; pharmaceutically acceptable salts thereof, and pharmaceutically acceptable esters thereof; which are useful for the treatment of COX-2 dependent disorders.
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- Regioselective aryl radical cyclisation. Part 2. Synthesis of octahydro-1H-dibenzo[a,d]cycloheptenes through 7-endo ring closure
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A simple convergent synthesis of trans- and cis-octahydro-1H-dibenzo[a,d]cycloheptenes 15a-c and 16a-c and 20a-c and 21a-c through implementation of a regioselective 7-endo-trig-aryl radical cyclisation of the respective 2-(o-bromoarylethyl)-1-methylenecy
- Ghosh, Ajit K.,Mukhopadhyaya, Jayanta K.,Ghatak, Usha Ranjan
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p. 2747 - 2755
(2007/10/03)
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