- Divergent synthesis of CF3-substituted polycyclic skeletons based on control of activation site of acid catalysts
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We report a divergent synthesis of CF3-substituted fused skeletons based on precise control of the activation site through the selection of acid catalysts. When trifluoromethyl ketones with an ortho-phenethyl ether group were treated with a catalytic amount of Sc(OTf)3, a hydride shift triggered C(sp3)-H bond functionalization proceeded to give CF3-substituted isochromene derivatives by selective activation of the carbonyl group. In sharp contrast, CF3-substituted bicyclo[3.3.1]nonanes were obtained exclusively via the activation of ether oxygen initiated sequential reactions (nucleophilic attack of carbonyl oxygen, and intramolecular Friedel-Crafts reaction) under strong Br?nsted acid catalysis (Tf2NH).
- Yokoo, Kazuma,Mori, Keiji
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- Rapid and Simple Access to α-(Hetero)arylacetonitriles from Gem-Difluoroalkenes
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A scalable cyanation of gem-difluoroalkenes to (hetero)arylacetonitrile derivatives was developed. This strategy features mild reaction conditions, excellent yields, wide substrate scope, and broad functional group tolerance. Significantly, in this reacti
- Hu, Dandan,Liu, Jiayue,Ren, Hongjun,Song, Jinyu,Zhang, Jun-Qi,Zhu, Guorong
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supporting information
p. 786 - 790
(2022/01/28)
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- The palladium(ii)-catalyzed regioselective ortho-C-H bromination/iodination of arylacetamides with in situ generated imidic acid as the directing group: Mechanistic exploration
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In the present study, we report the palladium(ii)-catalyzed regioselective ortho-C-H bromination/iodination of challenging arylacetamide derivatives using N-halosuccinimides as halogenating agents. Diverse arylacetamides underwent the regioselective ortho-bromination and iodination of aromatic C-H bonds in the presence of a reactive benzylic C(sp3)-H bond without installing any bulky auxiliaries via unfavorable six-membered metallacycles. Weak coordination, the use of ubiquitous primary amides for challenging C-H functionalization, the simple catalytic system and the wide substrate scope are the key features of this transformation. Further, the halogenated amide derivatives were transformed into a variety of valuable synthons. Detailed mechanistic studies revealed some interesting aspects concerning the reaction pathway. We present for the first time strong evidence for the formation of imidic acid (in situ) from primary amides under Br?nsted acid conditions that eventually aids in the stabilization of palladacycles of amide derivatives and drives regioselective C-X bond formation.
- Jaiswal, Yogesh,Kumar, Yogesh,Kumar, Amit
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p. 6809 - 6820
(2019/07/22)
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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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- 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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- 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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- Palladium-Catalyzed, ortho-Selective C-H Halogenation of Benzyl Nitriles, Aryl Weinreb Amides, and Anilides
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A palladium-catalyzed, ortho-selective C-H halogenation methodology is reported herein. The highlight of the work is the highly selective C(sp2)-H functionalization of benzyl nitriles in the presence of activated C(sp3)-H bond, which results in good yields of the halogenated products with excellent regioselectivity. Along with benzyl nitriles, aryl Weinreb amides and anilides have been evaluated for the transformation using aprotic conditions. Mechanistic studies yield interesting aspects with respect to the pathway of the reaction and the directing group abilities.
- Das, Riki,Kapur, Manmohan
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p. 1114 - 1126
(2018/06/18)
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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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- Synthesis of α-aryl esters and nitriles: Deaminative coupling of α-aminoesters and α-aminoacetonitriles with arylboronic acids
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Transition-metal-free synthesis of α-aryl esters and nitriles using arylboronic acids with α-aminoesters and α-aminoacetonitriles, respectively, as the starting materials has been developed. The reaction represents a rare case of converting C(sp3)-N bonds into C(sp3)-C(sp2) bonds. The reaction conditions are mild, demonstrate good functional-group tolerance, and can be scaled up. Touch base: A transition-metal-free protocol for the synthesis of α-aryl esters and nitriles by deaminative coupling is presented. Strong bases and transition-metal catalysts are not needed. The new synthetic method uses readily available starting materials and demonstrates wide substrate scope.
- Wu, Guojiao,Deng, Yifan,Wu, Chaoqiang,Zhang, Yan,Wang, Jianbo
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supporting information
p. 10510 - 10514
(2016/02/18)
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- Ionic liquid-induced conversion of methoxymethyl-protected alcohols into nitriles and iodides using [Hmim][NO3]
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This Letter reports a one-pot efficient conversion of methoxymethyl-ethers into their corresponding nitriles and iodides using the ionic liquid, 1-methyl-3H-imidazolium nitrate ([Hmim][NO3]) under microwave irradiation. A variety of products were prepared in high yields using this method.
- Noei, Jalil,Mirjafari, Arsalan
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supporting information
p. 4424 - 4426
(2014/08/05)
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- Microwave-promoted, one-pot conversion of alkoxymethylated protected alcohols into their corresponding nitriles, bromides, and iodides using [bmim][InCl4] as a green catalyst
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The Lewis acid room temperature ionic liquid, [bmim][InCl4], was found to be an efficient and green catalyst for the highly chemoselective and one-pot conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides, and iodides under microwave irradiation. The procedures are simple, rapid, and high yielding. The catalyst exhibited a remarkable reactivity and is reusable.
- Mirjafari, Arsalan,Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza
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supporting information; experimental part
p. 3274 - 3276
(2010/07/18)
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- Enantio- and diastereotopos differentiation in the palladium(II)-catalyzed hydrosilylation of bicyclo[2.2.1]alkene scaffolds with silicon-stereogenic silanes
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The palladium(II)-catalyzed hydrosilylation of meso-configured bicyclo[2.2.1]alkene scaffolds proved to be an invaluable model reaction for the development of reagent-controlled asymmetric transformations based on silicon-stereogenic silanes as stereoinducers. In the present investigation, the subtle structural requirements of the silane substitution pattern in enantiotopos-differentiating single hydrosilylations of a norbornene-type substrate are disclosed. Extension of this chemistry to a double hydrosilylation of norbornadiene entails a significant increase in stereochemical complexity. Although differentiation of enantiotopic positions by the chiral reagent is demanded in the first hydrosilylation, the same reagent must then differentiate diastereotopic positions in the second. Remarkably high stereocontrol was found in this double hydrosilylation with several silanes first used in the hydrosilylations of the norbornene-type system. Depending on the enantiomeric purity of the silane, C2- and Cs-symmetric adducts, respectively, were obtained. The identity of the key quaternary silanes was revealed by crystallographic analysis. By this method, the relative and absolute configurations were also assigned, which, in turn, imply that all enantiospecific substitutions at silicon proceed with stereoretention. On the basis of these solid-state structures, we also discuss the structural implications of silane substitution for the diastereoselectivity-determining step of this palladium(II)-catalyzed hydrosilylation reaction. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Rendler, Sebastian,Froehlich, Roland,Keller, Manfred,Oestreich, Martin
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supporting information; experimental part
p. 2582 - 2591
(2009/04/05)
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- Stereoselective alcohol silylation by dehydrogenative Si-O coupling: Scope, limitations, and mechanism of the Cu-H-catalyzed non-enzymatic kinetic resolution with silicon-stereogenic silanes
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Ligand-stabilized copper(I)hydride catalyzes the dehydrogenative Si-O coupling of alcohols and silanes-a process that was found to proceed without racemization at the silicon atom if asymmetrically substituted. The present investigation starts from this pivotal observation since silicon-stereogenic silanes are thereby suitable for the reagent-controlled kinetic resolution of racemic alcohols, in which asymmetry at the silicon atom enables discrimination of enantiomeric alcohols. In this full account, we summarizeour efforts to systematically examine this unusual strategy of diastereoselective alcohol silylation. Ligand (sufficient reactivity with moderately electron-rich monophosphines), silane (reasonable diastereocontrol with cyclic silanes having a distinct substitution pattern) as well as substrate identification (chelating donor as a requirement) areintroductorily described. With these basic data at hand, the substrate scope was defined employing enantiomerically enriched tert-butyl-substituted 1-silatetraline and highly reactive 1-si-laindane. The synthetic part is complemented by the determination of the stereochemical course at the silicon atom in the Si-O coupling step followed by its quantum-chemical analysis thus providing a solid mechanistic picture of this remarkable transformation.
- Rendler, Sebastian,Plefka, Oliver,Karatas, Betuel,Auer, Gertrud,Froehlich, Roland,Mueck-Lichtenfeld, Christian,Grimme, Stefan,Oestreich, Martin
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supporting information; scheme or table
p. 11512 - 11528
(2009/12/07)
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- SOME NEW ANALOGUES OF VERAPAMIL AND MEPAMIL. SYNTHESIS AND BASIC PHARMACOLOGICAL PROPERTIES
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Some new analogues of verapamil (Ia) and mepamil (Ib), calcium antagonists of arylkylamine type, were synthesized and screened for cardiovascular activities.The basic structure was modified a) on the phenyl ring, attached to the quaternary carbon, b) on the alkyl group, attached to the quaternary carbon and c) on the alkylamino group, attached in position 3 to the n-propyl fragment.Except of 2-(2-chlorophenyl)-2-isopropyl-5-(N-methylhomoveratrylamino)valeronitrile (VIa), all the synthesized compounds exhibited lower hypotensive activity, than the mother compound, verapamil.
- Butora, Gabriel,Blaha, Ludvik,Rajsner, Miroslav,Helfert, Ivan
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p. 1967 - 1981
(2007/10/02)
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- Method of treating nausea and vomiting with certain substituted-phenylalkylamino (and aminoacid) derivatives and other serotonin depleting agents
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A method for the treatment of emesis in a mammal, which method comprises administering to said mammal an emesis inhibiting amount of a compound which depletes serotonin in the brain of mammals; among which are compounds having the formula: STR1 wherein, R is selected from hydrogen, loweralkyl, trifluoromethyl, carboxyl, or loweralkoxycarbonyl; R1 and R2 are hydrogen or loweralkyl; Z is trifluoromethyl or halogen; the optical isomers and pharmaceutically acceptable salts thereof; two of the preferred compounds of the invention are fenfluramine and norfenfluramine.
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- Synthesis of Biological Markers in Fossil Fuels. 2. Synthesis and 13C NMR Studies of Substituted Indans and Tetralins
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Unambiguous syntheses of all possible methyl, ethyl, n-propyl, and n-butyl derivatives of indan and tetralin were developed using the Kumada coupling procedure involving the reaction of aryl or vinyl halides with Grignard reagents in the presence of nickel(II) chloride.An analysis of the 13C NMR spectra of these compounds was also completed.
- Adamczyk, Maciej,Watt, David S.,Netzel, Daniel A.
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p. 4226 - 4237
(2007/10/02)
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- 1,2-Dihydro-2-imino-1-(bromophenylalkyl)pyrimidines
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Compounds of the formula SPC1 Exhibit central nervous system stimulating properties and act as muscle relaxants.
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