- The cascade coupling/iodoaminocyclization reaction of trifluoroacetimidoyl chlorides and allylamines: metal-free access to 2-trifluoromethyl-imidazolines
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A metal-free cascade coupling/iodoaminocyclization reaction for the rapid assembly of 2-trifluoromethyl-imidazolines has been disclosed. The transformation applies readily accessible trifluoroacetimidoyl chlorides, allylamines andN-iodosuccinimides as the starting substrates, achieving an efficient and straightforward pathway to construct diverse imidazoline derivatives. Excellent efficiency of the reaction is observed (higher than 90% isolated yield for half of the examples), and the obtained imidazoline products bearing a pendent iodomethyl group could be easily transformed into other synthetically valuable compounds.
- Chen, Zhengkai,Du, Shiying,Song, Yufei,Wang, Le-Cheng,Wu, Xiao-Feng
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p. 6115 - 6119
(2021/07/21)
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- Visible-light-promoted radical alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester: Synthesis of oxazolines
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An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.
- Ding, Hao,Huang, Panyi,Jin, Can,Su, Weike,Sun, Bin,Yan, Zhiyang,Zhao, Haiyun
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- Nucleophilic Alkoxylations of Unactivated Alkyl Olefins and α-Methyl Styrene by Photoredox Catalysis
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N,N-diisobutylaminophenyl-phenothiazine is a strongly reducing catalyst that allows – for the first time – the photoredox catalytic addition of alcohols to alkyl olefins as non-activated substrates to products with Markovnikov orientation. The irradiation at 365 nm does not require any additional reagent. Using α-methyl styrene as activated substrate we additionally show that this photoredox catalytic method tolerates other functional groups, including allyl, alkynyl, cyanide, and even acid-labile Boc groups within the substrate scope.
- Seyfert, Fabienne,Mitha, Mathis,Wagenknecht, Hans-Achim
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p. 773 - 776
(2021/01/12)
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- Chiral selenide-catalyzed enantioselective synthesis of trifluoromethylthiolated 2,5-disubstituted oxazolines
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Chiral selenide-catalyzed enantioselective trifluoromethylthiolation of 1,1-disubstituted alkenes is disclosed. By this method, a variety of chiral trifluoromethylthiolated 2,5-disubstituted oxazolines were obtained in good yields with high enantioselectivities. This work not only provides a new pathway for the synthesis of chiral oxazolines, but also expands the library of chiral trifluoromethylthiolated molecules.
- Qin, Tian,Jiang, Quanbin,Ji, Jieying,Luo, Jie,Zhao, Xiaodan
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p. 1763 - 1766
(2019/02/20)
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- Catalytic Geminal Difluorination of Styrenes for the Construction of Fluorine-rich Bioisosteres
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A geminal difluorination of alkenes based on I(I)/I(III) catalysis is disclosed, which is compatible with a range of electronically and substitutionally diverse styrenes (27 examples, up to 89% yield). Employing inexpensive p-TolI as the organocatalyst, turnover is enabled by Selectfluor-mediated oxidation to generate the ArIF2 species in situ. Extension to include α-substituted styrenes bearing fluorine-containing groups is disclosed and provides an expansive platform for the generation of fluorine-rich architectures.
- Scheidt, Felix,Neufeld, Jessica,Sch?fer, Michael,Thiehoff, Christian,Gilmour, Ryan
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p. 8073 - 8076
(2019/01/04)
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- Flavin-Mediated Visible-Light [2+2] Photocycloaddition of Nitrogen- and Sulfur-Containing Dienes
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The [2+2] photocycloaddition mediated by 1-butyl-3-methyl-7,8-dimethoxyalloxazine (1) has been found to be an effective tool for cyclising ω-phenyl- and ω,ω′-diphenyl-4-aza-1,6-heptadienes, in which the nitrogen atom is protected by acylation or quaternisation, towards the synthesis of a variety of phenyl- and diphenyl-3-azabicyclo[3.2.0]heptanes and their corresponding quaternary salts. Thia derivatives, with the sulfur atom in the form of a sulfone group, underwent an analogous cyclisation. Advantageously, visible light (400 nm) was used for the cycloadditions in the presence of 1, in contrast to the previously described procedures affording azabicyclo[3.2.0]heptanes by using UV irradiation. Practical applications are demonstrated through the synthesis of bicyclic quaternary ammonium salts, 6-phenyl-azabicyclo[3.2.0]heptanes known to exhibit biological activity or chiral spiro ammonium salts. Flavin 1 was also found to promote the efficient E→Z isomerisation of electron-rich cinnamyl derivatives to produce mixtures enriched with the Z isomer (with Z/E ratios of up to 77:23).
- Jirásek, Michael,Straková, Karolína,Nevesely, Tomá?,Svobodová, Eva,Rottnerová, Zdeňka,Cibulka, Radek
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p. 2139 - 2146
(2017/04/24)
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- Solvent-dependent enantiodivergence in the chlorocyclization of unsaturated carbamates
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A remarkable solvent-controlled enantiodivergence is seen in the hydroquinidine 1,4-phthalazinediyl diether ((DHQD)2PHAL)-catalyzed chlorocyclization of unsaturated carbamates. Eyring plot analyses of this previously unreported reaction are used to probe and compare the R- and S-selective pathways. In the CHCl3/hexanes solvent system, the pro-R process shows a surprising increase in selectivity with increasing temperature. These studies point to a strongly solvent-dependent entropy-enthalpy balance between the pro-R and pro-S pathways. Two solvents, two enantiomers: Enantiodivergent hydroquinidine 1,4-phthalazinediyl diether ((DHQD) 2PHAL)-catalyzed chlorocyclization of unsaturated carbamates, controlled solely by the choice of solvent, yields oxazolidinones in high enantioselectivity (see scheme; DCDMH=1,3-dichloro-5,5-dimethyl hydantoin). The origin of the observed enantiodivergence is traced back to a solvent-selected entropy-enthalpy balance between pro-R and pro-S pathways that dictates the course of the reaction. Copyright
- Garzan, Atefeh,Jaganathan, Arvind,Salehi Marzijarani, Nastaran,Yousefi, Roozbeh,Whitehead, Daniel C.,Jackson, James E.,Borhan, Babak
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p. 9015 - 9021
(2013/07/26)
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- Conformationally restricted pyrrolidines by intramolecular [2+2] photocycloaddition reactions
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Intramolecular [2+2] photocycloaddition reactions of diversely substituted N-Boc protected 4-(allylaminomethyl)-2(5H)-furanones resulted in rigid products (53-75%) with three spatially defined positions for further functionalisation. The Royal Society of Chemistry.
- Fort, Diego A.,Woltering, Thomas J.,Nettekoven, Matthias,Knust, Henner,Bach, Thorsten
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p. 2989 - 2991
(2013/05/09)
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- Asymmetric hydrogenation of protected allylic amines
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A general method for the enantioselective hydrogenation of protected allylic amine derivatives is described. This procedure relies on the generation of a cationic ruthenium complex with the axially chiral ligand (-)-TMBTP. The utility is highlighted by th
- Steinhuebel, Dietrich P.,Krska, Shane W.,Alorati, Anthony,Baxter, Jenny M.,Belyk, Kevin,Bishop, Brian,Palucki, Michael,Sun, Yongkui,Davies, Ian W.
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supporting information; experimental part
p. 4201 - 4203
(2010/11/19)
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- Copper-catalyzed allylic hydroxyamination and amination of alkenes with Boc-hydroxylamine
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Olefins react regioselectively with Boc-NHOH in the presence of Cu(I,II) salts to produce allyl-N(OH)(Boc) derivatives, apparently via the intermediacy of Boc-NO; yields and rates are dramatically improved by the addition of H 2O2. The corresponding allylamine derivatives, allyl-NH(Boc), are formed selectively from Boc-NHOH/olefin with CuBr/P(OEt) 3.
- Kalita, Biswajit,Nicholas, Kenneth M.
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p. 1451 - 1453
(2007/10/03)
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- Ring closing metathesis of phenyl-substituted dienes
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A series of phenyl-substituted heterodienes 2a-f and 6 was prepared and subjected to ring closing metathesis (RCM) to give differently phenyl- substituted dihydropyrroles and dihydrofuran.
- Bujard,Briot,Gouverneur,Mioskowski
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p. 8785 - 8788
(2007/10/03)
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- Allyl amine MAO inhibitors
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Compounds of the formula STR1 wherein: R is phenyl, phenyl monosubstituted, disubstituted, or trisubstituted by (C1 -C8) alkyl, (C1 -C8)alkoxy, hydroxy, chlorine, bromine, iodine, fluorine, trifluoromethyl, nitr
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