- Enantioselective Iodine(III)-Mediated Synthesis of α-Tosyloxy Ketones: Breaking the Selectivity Barrier
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The development of practical methods to access chiral nonracemic α-substituted ketones is of particular importance due to their ubiquitous nature. Unprecedented levels of enantioselectivity are reported for the synthesis of α-tosyloxy ketones, using enol esters and chiral iodine(III) reagents. The reaction can be performed under both stoichiometric and catalytic conditions. These results suggest widely different reaction mechanisms for the reaction of ketones versus enol esters, supporting recent computational insights.
- Basdevant, Benoit,Legault, Claude Y.
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supporting information
p. 4918 - 4921
(2015/10/12)
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- Study of the Reactivity of [Hydroxy(tosyloxy)iodo]benzene Toward Enol Esters to Access α-Tosyloxy Ketones
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The reactivity of enol esters toward [hydroxy(tosyloxy)iodo]benzene (HTIB) was assessed. These substrates were found to be rapidly converted in high yields to their corresponding α-tosyloxy ketones. This transformation demonstrates that these substrates can act as ketone surrogates. The scope of the method was investigated and aromatic, aliphatic, and cyclic enol esters were found to be suitable substrates for the reaction. The relative reactivity of a model substrate toward HTIB and m-CPBA was investigated, and it was found that the reaction could be performed under catalytic conditions.
- Basdevant, Benoit,Legault, Claude Y.
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p. 6897 - 6902
(2015/10/06)
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- General Method for the Preparation of Electron-Deficient Imidazo[1,2-a]pyridines and Related Heterocycles
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A new annulation method for the preparation of the imidazo[1,2-a]pyridine ring system under mild conditions is presented. Treatment of a 2-aminopyridine with a dimethylketal tosylate in acetonitrile at elevated temperature (80-140°C) in the presence of catalytic Sc(OTf)3 provides the imidazo[1,2-a]pyridine product in good yield. The annulation method is broadly applicable to electron-poor 2-aminopyridines and displays a complementary profile to the classic preparation of the imidazo[1,2-a]pyridine ring system by reaction of a bromoketone with electron-rich and -neutral substrates. The scope of the process and mechanistic considerations are discussed.
- McDonald, Ivar M.,Peese, Kevin M.
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supporting information
p. 6002 - 6005
(2016/01/09)
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- 2,4,6-Tris(4-iodophenoxy)-1,3,5-triazine as a new recyclable "iodoarene" for in situ generation of hypervalent iodine(III) reagent for α-tosyloxylation of enolizable ketones
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The synthesis of 2,4,6-tris[(4-iodo)phenoxy)]-1,3,5-triazine 6, as a new recyclable nonpolymeric analogue of iodobenzene is achieved using the reaction of 2,4,6-trichloro-1,3,5-triazine with 4-iodophenol in the presence of KOH. The application of 6 as a r
- Thorat, Prerana B.,Bhong, Bhagyashree Y.,Shelke, Amol V.,Karade, Nandkishor N.
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p. 3332 - 3335
(2014/06/09)
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- One-Pot Protocol for Synthesis of -Organosulfonyloxy Ketones from Secondary Alcohols Using Hypervalent Iodine(V)-Mediated Oxidations
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Tosyloxy ketones and -mesyloxy ketones were directly prepared from alcohols in one pot by treatment with hypervalent iodine(V) reagents in combination with p-toluenesulfonic acid and methanesulfonic acid, respectively, in moderate to good yields. Reaction
- Deshmukh, Swapnil S.,Huddar, Sameerana N.,Akamanchi, Krishnacharya G.
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experimental part
p. 3101 - 3110
(2009/11/30)
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- M-iodosylbenzoic acid: Recyclable hypervalent iodine reagent for-tosyloxylation and-mesyloxylation of ketones
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m-Iodosylbenzoic acid-mediated reactions of various carbonyl compounds provided-organosulfonyloxy carbonyl compounds in good yields. The final products could be easily isolated without any chromatographic purification by simple treatment of the crude mixt
- Yusubov, Mekhman S.,Funk, Tatyana V.,Yusubova, Roza Y.,Zholobova, Galina,Kirschning, Andreas,Park, Joo Yeon,Chi, Ki-Whan
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experimental part
p. 3772 - 3784
(2009/12/06)
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- A new application of hypervalent iodine (λ5) reagents with organosulfonic acids for direct α-organosulfonyloxylation carbonyl compounds
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Hypervalent iodine (λ5) reagents in combination with p-toluenesulfonic acid when reacted with ketones under reflux temperature in acetonitrile gave α-tosyloxy ketones in moderate to excellent yields. The reaction was developed further for both
- Mahajan, Ulhas S.,Akamanchi, Krishnacharya G.
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experimental part
p. 987 - 990
(2009/04/04)
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- Solvent-free synthesis of 1-(p-toluenesulfonyloxy)-1,2-benziodoxol-3(1H)-one from Dess-Martin periodinane and its synthetic utility for α-tosyloxylation of ketones
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The solvent-free synthesis of 1-(p-toluenesulfonyloxy)-1,2-benziodoxol-3(1H)-one is reported from Dess-Martin periodinane and p-toluenesulfonic acid monohydrate using a grinding technique and is subsequently utilized for the α-tosyloxylation of a range of enolisable ketones.
- Karade, Nandkishor N.,Tiwari, Girdharilal B.,Shinde, Sandeep V.,Gampawar, Sumeet V.,Kondre, Jeevan M.
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p. 3441 - 3443
(2008/09/21)
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- Direct α-oxytosylation of carbonyl compounds: One-pot synthesis of heterocycles
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N-Methyl-O-tosylhydroxylamine is an effective reagent for the direct α-oxytosylation of carbonyl compounds. The reactions proceed smoothly at room temperature in the presence of both moisture and air and functional group tolerance in the substrate is good. With nonsymmetrical substrates regioselectivity for primary over secondary centers is observed and complete regiospecificity for primary over tertiary centers is obtained. Addition of a bis-heteronucleophile directly to the crude reaction mixture in a one-pot process leads to the corresponding heterocyclic product.
- John, Oliver R. S.,Killeen, Niall M.,Knowles, Deborah A.,Yau, Sze Chak,Bagley, Mark C.,Tomkinson, Nicholas C. O.
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p. 4009 - 4012
(2008/02/11)
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- [Hydroxy(tosyloxy)iodo]benzene mediated α-azidation of ketones
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Reaction of various ketones with [hydroxy(tosyloxy)iodo]benzene (HTIB) followed by treatment of the α-tosyloxy ketones thus generated in situ with NaN3 offers a one-pot procedure for the synthesis of α-azido ketones. The HTIB used in this conversion may also be generated in situ by using iodosobenzene in combination with p-toluene-sulphonic acid.
- Prakash, Om,Pannu, Kamaljeet,Prakash, Richa,Batra, Anita
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p. 523 - 527
(2007/10/03)
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- Solvent-free reactions with hypervalent iodine reagents
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(Chemical Equation Presented) We describe solvent-free reactions for the synthesis of hypervalent iodine reagents and their use in solid-state reactions. Improved yields and higher purities of the products are observed.
- Yusubov, Mekhman S.,Wirth, Thomas
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p. 519 - 521
(2007/10/03)
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- Homogeneous supported synthesis using ionic liquid supports: Tunable separation properties
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(Chemical Equation Presented) We report a homogeneous supported version of Koser's salt based on a room-temperature ionic liquid (RTIL) support. By altering the nature of the RTIL, a material was developed that was stable, recyclable, and readily separable from the tosyloxylated ketone products just by using variations in solvent polarity. A similar approach should be applicable to a wide range of supported catalysts and reagents.
- Handy, Scott T.,Okello, Maurice
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p. 2874 - 2877
(2007/10/03)
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- Novel oxidative α-tosyloxylation of alcohols with iodosylbenzene and p-toluenesulfonic acid and its synthetic use for direct preparation of heteroaromatics
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α-Tosyloxyketones and α-tosyloxyaldehydes were directly prepared from alcohols by treatment with iodosyl-benzene and p-toluenesulfonic acid monohydrate in good yields. This method can be used for the direct preparation of thiazoles, imidazoles, and imidaz
- Ueno, Makoto,Nabana, Takahiro,Togo, Hideo
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p. 6424 - 6426
(2007/10/03)
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- Reactivities of novel [hydroxy(tosyloxy)iodo]arenes and [hydroxy(phosphoryloxy)iodo]arenes for α-tosyloxylation and α-phosphoryloxylation of ketones
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Novel [hydroxy(tosyloxy)iodo]arenes bearing 2-thienyl, 3-thienyl, N-tosyl-4-pyrazolyl, 3-trifluoromethylphenyl, and 3,5-bis(trifiuoromethy)phenyl as an aromatic group, and [hydroxy(phosphoryloxy)iodo]arenes bearing N. tosyl-4-pyrazolyl, 3-trifluoromethylp
- Nabana, Takahiro,Togo, Hideo
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p. 4362 - 4365
(2007/10/03)
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- α-tosyloxyketones: Convenient [4+3] cycloaddition precursors
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A concise, simple two-step method for the preparation of [4+3] cycloadducts from ketones using Koser's reagent and trifuoroethanol-triethylamine has been developed. This sequence affords yields similar to those obtained using the α-halo and α-mesyloxyketo
- Handy, Scott T.,Okello, Maurice
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p. 489 - 491
(2007/10/03)
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- Organic reactions in ionic liquids: α-tosyloxylation of ketones
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The room temperature ionic liquid, n-butylpyridinium tetrafluoroborate (BPyBF4) is used as a ''green'' recyclable alternative to classical molecular solvents for the α-tosyloxylation of ketones.
- Xie, Yuan Xie,Chen, Zhen Chu,Zheng, Qin Guo
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p. 618 - 619
(2007/10/03)
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- Synthesis of α,ω-dicarboxylic acid dimethyl esters from cycloalkanones
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Reaction of cycloalkanones with [hydroxy(2,4-dinitrobenzenesulfonyloxy)iodo]benzene and subsequent treatment of α-[(2,4-dinitrobenzene)sulfonyl]oxy cycloalkanone intermediates with Oxone and PTSA in MeOH-H2O (6:1, v/v) solution provided dicarboxylic acid dimethyl esters in high yields.
- Lee, Jong Chan,Ku, Chang Hoe
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p. 1679 - 1680
(2007/10/03)
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- Novel preparation and reactivity of poly[4-hydroxy(tosyloxy)iodo]styrenes
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Poly[4-hydroxy(tosyloxy)iodo]styrene (high M.W.) and poly{α-methyl[4-hydroxy(tosyloxy)iodo]styrene} (low M.W.) were prepared from polystyrene (average M.W. = 45,000) and poly(α-methylstyrene) (average M.W. = 6,200), respectively, and their reactivities fo
- Abe,Sakuratani,Togo
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- Highly Efficient α-Organosulfonyloxylation of Carbonyl Compounds under Microwave Irradiation
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Iodobenzene diacetate and organosulfonic acid mediated reaction of various carbonyl compounds under solventless microwave irradiation provided α-organosulfonyloxy carbonyl compounds in high yields.
- Lee, Jong Chan,Choi, Ju-Hee
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p. 234 - 235
(2007/10/03)
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- 1-[hydroxy(sulfonyloxy)iodo]-1H,1H-perfluoroalkanes: Stable, fluoroalkyl analogs of Koser's reagent
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1-[Hydroxy(sulfonyloxy)iodo]-1H,1H/-perfluoroalkanes 3 [RfCH2I(OH)OSO2R; R = CH3, CH3, p-CH3C6H4, Rf = CF3, C2F5] can be pr
- Zhdankin, Viktor V.,Kuehl, Chris J.,Simonsen, Angela J.
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p. 8272 - 8276
(2007/10/03)
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- 1-[Hydroxy(sulfonyloxy)iodo]-2,2,2-trifluoroethanes, CF3CH2I(OH)OSO2R: Stable, fluoroalkyl analogs of Koser's reagent
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1-[Hydroxy(sulfonyloxy)iodo]-2,2,2-trifluoroethanes [CF3CH2I(OH)OSO2R; R = CH3, CF3, p-CH3C6H4] can be prepared in two steps from trifluoroethyliodide by oxidation with pertrifluoroacetic acid and subsequent reaction with TsOH, MsOH, or Me3SiOTf. Reaction of the tosylate derivative 3 with silyl enol ethers affords α-tosyloxyketones, while triflate 5 smoothly reacts with trimethylsilylbenzene to give the respective trifluoroethyl(phenyl)iodonium triflate 8.
- Zhdankin, Viktor V.,Kuehl, Chris J.,Simonsen, Angela J.
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p. 2203 - 2206
(2007/10/02)
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- Reactivity of 2-chloro- and 2-(tosyloxy)cyclohexanones towards anions electrogenerated at carbonium and nitrogen atoms. Electrochemically induced Favorskii rearrangement
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Carbonium and nitrogen anions were generated by cathodic reduction of 6, 7 and 8 or by deprotonation of 9 and 10 (by means of electrogenerated bases).Their reactivity towards α-substituted ketones 1 and 2 was studied.The reaction products 5b-d, 4b and 3 are formed according to the Favorskii rearrangement, substitution, and formal reduction mechanisms, respectively.In most cases, the reaction pathway appears to be driven by the applied electric potential.The Favorskii rearrangement undergone by 1 and 2 under electrochemical conditions can also be induced by nitrogen (Ph-NH--Ph) and carbonium (CH3COC-HCO2Et) anions, which have never been used before in this kind of reaction. - Keywords: probase / Favorskii rearrangement / electrogenerated anions / α-substituted cyclohexanones
- Angelis, F. De,Feroci M.,Inesi, A.
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p. 712 - 719
(2007/10/02)
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- Ultrasound Promoted Hypervalent Iodine Reactions: α-Tosyloxylation of Ketones with Benzene
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Ultrasound enhances substantially the rats of α-tosyloxylation of ketones with benzene and thus provides a direct, quick, and mild method of tosyloxylation of ketones without the generation of timeconsuming intermediates such as tri
- Tuncay, Atilla,Dustman, John A.,Fisher, George,Tuncay, Crystal I.,Suslick, Kenneth S.
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p. 7647 - 7650
(2007/10/02)
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- Reaction of benzene and benzene with Trimethylsilyl Enol Ethers. A New General Method for α-Sulfonyloxylation of Carbonyl Compounds
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Reaction of benzene (1) with trimethylsilyl enol ethers of aromatic ketones 4a-d, alicyclic ketone 7, aliphatic ketone 10, and esters 13a-c in dichloromethane at room temperature gives good yields of α-(tosyloxy)carbonyl compounds 5
- Moriarty, Robert M.,Penmasta, Raju,Awasthi, Alok K.,Epa, W. Ruwan,Prakash, Indra
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p. 1101 - 1104
(2007/10/02)
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