- Silver-promoted (radio)fluorination of unsaturated carbamates via a radical process
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The intramolecular fluorocyclization of unsaturated carbamates is described here using a hypervalent iodine reagent in the presence of a silver catalyst. Both (hetero)aryl-substituted olefins and acrylamides can be utilized as effective substrates. Preliminary mechanistic investigations suggest that the reaction proceeds via a cyclization/1,2-(hetero)aryl migration/fluorination cascade involving an unusual radical process. Furthermore, starting from no-carrier-added [18F]TBAF, a simple one-pot, two-step cascade method was developed for the generation of 18F-labeled heterocycles with high radiochemical purity.
- Yang, Bin,Chansaenpak, Kantapat,Wu, Hongmiao,Zhu, Lin,Wang, Mengzhe,Li, Zibo,Lu, Hongjian
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supporting information
p. 3497 - 3500
(2017/03/30)
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- A biosynthetically inspired route to substituted furans using the Appel reaction: Total synthesis of the furan fatty acid F5
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Appel reaction conditions have been harnessed to affect a mild biosynthetically inspired dehydration of endoperoxides to deliver multi-substituted electron rich furans. Unlike traditional dehydrative procedures, this method is metal and acid free, and can be achieved under redox neutral conditions. It is general for a range of aryl and alkyl substituted endoperoxides, and is functional group tolerant. Furthermore, this procedure has been used to deliver an effective total synthesis of the furan fatty acid (FFA) F5.
- Lee, Robert J.,Lindley, Martin R.,Pritchard, Gareth J.,Kimber, Marc C.
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supporting information
p. 6327 - 6330
(2017/07/11)
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- LIQUID CRYSTAL COMPOUND AND LIQUID CRYSTAL MIXTURE CONTAINING CYCLOPROPYL
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PROBLEM TO BE SOLVED: To provide a compound represented by the general formula I. SOLUTION: There is provided a liquid crystal compound containing cyclopropyl represented by the formula I which has an excellent use value since it has not only a positive or negative dielectric anisotropy(?ε), a proper refractive index anisotropy (?n), a relatively high clear point (CP), outstanding low temperature miscibility with the other liquid crystals and a low rotational viscosity but also has excellent stability to ultraviolet rays and excellent stability to high temperatures. The compound is applied for the preparation of a positive or negative liquid crystal compound and can be used for a passive or active matrix display. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0066
(2018/09/25)
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- Reductive and brominative termination of alkenol cyclization in aerobic cobalt-catalyzed reactions
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(Chemical Equation Presented) Tetrahydrofur-2-ylmethyl radicals were stereoselectively generated from substituted pent-4-en-1-ols in aerobic cobalt(II)-catalyzed oxidations. Intermediates were trapped with cyclohexa -1,4-diene, γ-terpinene, BrCCl3, diethyl dibromomalonate, or electron-deficient olefins such as acrylonitrile or dimethyl fumarate to afford functionalized tetrahydrofurans in synthetically useful yields.
- Schuch, Dominik,Fries, Patrick,Doenges, Maike,Perez, Barbara Menendez,Hartung, Jens
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supporting information; experimental part
p. 12918 - 12920
(2009/12/05)
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- β SECRETASE INHIBITOR
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Disclosed is a compound represented by the formula (1) below which is useful as a drug for treating Alzheimer's disease, or a pharmaceutically acceptable salt thereof. (1) [In the formula, R1 represents a group represented by the following formula (2): (2) (wherein X represents a nitrogen atom or a group expressed as C(R5); Y represents a nitrogen atom or a group expressed as C(R6); and R5 and R6 independently represent a hydrogen atom or the like) or the like; m represents an integer of 1-6; L1 represents a single bond or the like; R2 represents a hydrogen atom, a substituted or unsubstituted alkyl group or the like; R3 represents a hydrogen atom or the like; L2 represents a single bond or the like; and R4 represents a hydrogen atom, a substituted or unsubstituted aryl group or the like.]
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Page/Page column 47-48
(2008/06/13)
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- Pheromones, 89.- Wittig Syntheses of Alkyl-Branched and Cyclic Analogs of (Z)-5-Decenyl Acetate, the Sex Pheromone of Agrotis segetum (Lepitoptera: Noctuidae)
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By means of (Z)-selective Wittig olefination alkyl-branched and cyclic analogs of (Z)-5-decenyl acetate, the sex pheromone of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae), have been synthesized. Key Words: Pheromones / (Z)-5-decenyl acetate / Wittig reactions / Agrotis segetum
- Albores, Martha,Bestmann, Hans Juergen,Doehla, Bodo,Hirsch, Hans-Ludwig,Roesel, Peter,Vostrowsky, Otto
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p. 231 - 236
(2007/10/02)
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- Opening of a Cyclopropyl Ring in (Diphenylcyclopropyl)alkenes Promoted by Electron Transfer from Potassium 4,4'-Di-tert-butylbiphenyl Radical Anion and X-ray and Theoretical Calculations of the Structure of (Z)-1,2-Bis(trans-2,trans-3-diphenylcyclopropyl)ethene
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We have prepared the (diphenylcyclopropyl)alkenes 1a-c and studied their reductions, using potassium 4,4'-di-tert-butylbiphenyl radical anion (DBB.-) as an electron source.Spectra analyses of the reaction products reveal that the double bond of the alkene stayed intact, whereas the cyclopropyl moiety was cleaved to provide alkenes 2a-c.When the reaction was carried out with a simple cyclopropylalkene without phenyl substituents (1e), the starting material was fully recovered.This indicates that the opening of the cyclopropyl ring in the alkenes is promoted by electron transfer from potassium DDB.- onto the phenyl rings attached to the cyclopropyl moiety.Two mechanisms were considered: (1) opening of the cyclopropyl via a cyclopropylcarbinyl to homoallylcarbinyl radical rearrangement (CPCRR) with potassium DBB.- as the le- reductant, with electron transfer to the phenyl rings attached to the cyclopropyl moiety, and (2) 2e- transfer to the phenyl rings and opening of the cyclopropyl moiety via an anionic rearrangement(CPCAR). (Z)-1-(trans-2,trans-3-Diphenylcyclopropyl)butene (1c) was used as a model for AM1 calculations which establish that the isomeric form of the radical anion product with opened cyclopropyl ring (1c.- form 1) is about 7 kcal/mol lower in energy than an isomeric form in which the cyclopropyl ring is closed (1c.- form 2).This suggests that the opening of the cyclopropyl ring is likely to happen through CPCRR rather than CPCAR.The X-ray crystal structure of (Z)-1,2-bis(trans-2,trans-3-diphenylcyclopropyl)ethene (1a) shows the two phenyl rings to be completely out of the cyclopropyl ring plane.The average C-C bond distance for the cyclopropyl moiety in the trans-2,trans-3-diphenylcyclopropyl rings is 1.562 Angstroem, which is longer than the average bond distance in unsubstituted cyclopropyl rings.The gas-phase structures as calculated by AM1, PM3, and MNDO molecular orbital methods are all quite similar and agree closely with the X-ray structure.However, MNDO gave more satisfactory results than AM1 and PM3 for bond distances and bond angles and deviated more for torsion angles.The latter is reflected by the relatively large difference in the heat of formations (7 kcal/mol) of the gas-phase fully optimized structure and the X-ray structure.
- Karaman, Rafik,He, Gong-Xin,Chu, Felice,Blasko, Andrei,Bruice, Thomas C.
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p. 438 - 443
(2007/10/02)
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