- Photoredox-Catalyzed Intramolecular Difluoromethylation of N-Benzylacrylamides Coupled with a Dearomatizing Spirocyclization: Access to CF2H-Containing 2-Azaspiro[4.5]deca-6,9-diene-3,8-diones
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A visible light-mediated difluoromethylation of N-benzylacrylamides with HCF2SO2Cl as the HCF2 radical precursor is described. The reaction incorporates a tandem cyclization/dearomatization process to afford various difluoromethylated 2-azaspiro[4.5]deca-6,9-diene-3,8-diones bearing adjacent quaternary stereocenters under mild conditions in moderate to excellent yields.
- Zhang, Zuxiao,Tang, Xiao-Jun,Dolbier, William R.
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- Efficient cu-catalyzed atom transfer radical addition reactions of fluoroalkylsulfonyl chlorides with electron-deficient alkenes induced by visible light
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Fluoroalkylsulfonyl chlorides, RfSO2Cl, in which Rf=CF3, C4F9, CF2H, CH2F, and CH2CF3, are used as a source of fluorinated radicals to add fluoroalkyl groups to electron-deficient, unsaturated carbonyl compounds. Photochemical conditions, using Cu mediation, are used to produce the respective α-chloro-β-fluoroalkylcarbonyl products in excellent yields through an atom transfer radical addition (ATRA) process. Facile nucleophilic replacement of the α-chloro substituent is shown to lead to further diverse functionalization of the products.
- Tang, Xiao-Jun,Dolbier, William R.
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supporting information
p. 4246 - 4249
(2015/04/14)
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- Photoredox-Catalyzed Tandem Insertion/Cyclization Reactions of Difluoromethyl and 1,1-Difluoroalkyl Radicals with Biphenyl Isocyanides
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Using visible-light photoredox conditions, difluoromethylation and 1,1-difluoroalkylation of biphenyl isocyanides have allowed the synthesis of a series of 6-(difluoromethyl)- and 6-(1,1-difluoroalkyl)phenanthridines via tandem addition/cyclization/oxidation processes. The reactions are carried out in wet dioxane at room temperature using fac-Ir(ppy)3 as catalyst to form a large variety of substituted phenanthridine products in good to excellent yield.
- Zhang, Zuxiao,Tang, Xiaojun,Dolbier, William R.
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supporting information
p. 4401 - 4403
(2015/09/28)
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- Direct Photoredox-Catalyzed Reductive Difluoromethylation of Electron-Deficient Alkenes
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Photoredox-catalyzed reductive difluoromethylation of electron-deficient alkenes was achieved in one step under tin-free, mild and neutral conditions. This protocol affords a facile method to introduce RCF2 (R=H, Ph, Me, and CH2N3) groups at sites β to electron-withdrawing groups. It was found that TTMS (tris(trimethylsilyl)silane) served nicely as both the H-atom donor and the electron donor in the catalytic cycle. Experimental and DFT computational results provided evidence that RCF2 (R=H, Ph, Me) radicals are nucleophilic in nature.
- Tang, Xiao-Jun,Zhang, Zuxiao,Dolbier, William R.
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supporting information
p. 18961 - 18965
(2016/01/26)
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- Photoredox-catalyzed tandem radical cyclization of N-arylacrylamides: General methods to construct fluorinated 3,3-disubstituted 2-oxindoles using fluoroalkylsulfonyl chlorides
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Fluorinated radicals were generated from RfSO2Cl by photoredox catalysis under mild conditions, where Rf = n-C4F9, CF3, CF2H, CH2F, CH2CF3, and CF2CO2Me. This method provided a general way to construct fluorinated 2-oxindoles from reaction with N-arylacrylamides via a proposed tandem radical cyclization process.
- Tang, Xiao-Jun,Thomoson, Charles S.,Dolbier, William R.
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supporting information
p. 4594 - 4597
(2015/01/08)
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- Process for the synthesis of hydrogenofluoromethylenesulphonyl radical derivatives
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The invention concerns a method for synthesis of hydrogenofluoromethylenesulphonyl radical derivatives, comprising: a) a step which consists in condensing a thiolate (that is a monoalkyl sulphide salt) with a compound having a sp; 3hybridized carbon bearing a hydrogen, a fluorine, a heavy halogen selected among chlorine, bromine and iodine and an electron-attracting group selected among fluorine and those whereof the is not less than 0.2, advantageously than 0.4; b) a step which consists in oxidizing the compound obtained in step a). The invention is applicable to the synthesis of various compounds having a suphinyl or sulphonyl group.
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Page/Page column 5
(2008/06/13)
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- A new synthesis of difluoromethanesulfonamides - A novel pharmacophore for carbonic anhydrase inhibition
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Preparation of the key intermediate carboxydifluoromethanesulfonamide provides direct synthetic access to a wide range of novel difluoromethanesulfonamides, including the acetazolamide analogue (2-ethanoylamino-1,3,4-thiadiazol-5-yl)-difluoromethanesulfonamide. Their water solubility and stability, ether partition coefficient, pK, and submicromolar dissociation constants for human carbonic anhydrase isozyme II (HCA II) make them promising candidates for topical glaucoma therapy.
- Boyle, Nicholas A.,Chegwidden, W. Richard,Blackburn, G. Michael
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p. 222 - 224
(2007/10/03)
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- METHOD FOR PRODUCING BENZYL(DIFLUOROMETHYL) SULFIDE COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing a benzyl(difluoromethyl) sulfide compound without using N,N-dimethylformamide while preventing the mixing of used solvent into waste water to reduce the waste water disposal load. SOLUTION: This benzyl(difluoromethyl) sulfide compound expressed by formula (4) (R is hydrogen atom, an alkyl, or the like; and (n) is 1-5) is produced by reacting a benzyl mercaptan metal salt expressed by formula (1) (R and n are same as those defined above; X1 is an alkali metal or an alkaline earth metal; and (m) is 1 when X1 is an alkali metal and is 2 when X1 is an alkaline earth metal) with a halogenated difluoromethane expressed by formula (2) (X2 is a halogen atom) in a binary layer system composed of a water phase and an organic phase.
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Page/Page column 9
(2010/02/11)
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