- Mechanistic Investigation and Optimization of Photoredox Anti-Markovnikov Hydroamination
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The reaction mechanism and the origin of the selectivity for the photocatalytic intermolecular anti-Markovnikov hydroamination of unactivated alkenes with primary amines to furnish secondary amines have been revealed by time-resolved laser kinetics measur
- Ganley, Jacob M.,Knowles, Robert R.,Nocera, Daniel G.,Qin, Yangzhong,Sun, Rui,Zhu, Qilei
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supporting information
p. 10232 - 10242
(2021/07/26)
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- Anti-Markovnikov Hydroamination of Unactivated Alkenes with Primary Alkyl Amines
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We report here a photocatalytic method for the intermolecular anti-Markovnikov hydroamination of unactivated olefins with primary alkyl amines to selectively furnish secondary amine products. These reactions proceed through aminium radical cation (ARC) intermediates and occur at room temperature under visible light irradiation in the presence of an iridium photocatalyst and an aryl thiol hydrogen atom donor. Despite the presence of excess olefin, high selectivities are observed for secondary over tertiary amine products, even though the secondary amines are established substrates for ARC-based olefin amination under similar conditions.
- Miller, David C.,Ganley, Jacob M.,Musacchio, Andrew J.,Sherwood, Trevor C.,Ewing, William R.,Knowles, Robert R.
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supporting information
p. 16590 - 16594
(2019/11/03)
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- Intermolecular Anti-Markovnikov Hydroamination of Unactivated Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer
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Here we report a catalytic method for the intermolecular anti-Markovnikov hydroamination of unactivated alkenes using primary and secondary sulfonamides. These reactions occur at room temperature under visible light irradiation and are jointly catalyzed by an iridium(III) photocatalyst, a dialkyl phosphate base, and a thiol hydrogen atom donor. Reaction outcomes are consistent with the intermediacy of an N-centered sulfonamidyl radical generated via proton-coupled electron transfer activation of the sulfonamide N-H bond. Studies outlining the synthetic scope (>60 examples) and mechanistic features of the reaction are presented.
- Zhu, Qilei,Graff, David E.,Knowles, Robert R.
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supporting information
p. 741 - 747
(2018/01/26)
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- Phosphine/Lewis acid mediated Reformatsky-type reaction of α-bromoketone or -thioester derivatives
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The combination of (?-tolyl)3P/TiCl4 effectively promoted the Reformatsky-type reaction of α-bromoketone or -thioester derivatives with various aldehydes, and the corresponding β-hydroxy carbonyl compounds were obtained in good yield
- Hashimoto, Yukihiko,Kikuchi, Satoshi
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p. 126 - 127
(2007/10/03)
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- A convergent asymmetric synthesis of γ-butenolides
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The addition of aldehydes to the new enantiomerically pure lithiated sulfoxide-orthoester 13 yielded γ-butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The cyclocondensation with ketones was less stereoselective. This new asymmetric synthesis of γ-butenolides has been applied to a convergent preparation of the antifungal antibiotic (+)-cerulenin.
- Renard, Marc,Ghosez, Léon A.
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p. 2597 - 2608
(2007/10/03)
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- Formation by SRN1 reactions and 1H N.M.R. properties of sterically encumbered 2,4,6-triaIkyIphenyl p-nitrobenzyl sulfides
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Sterically hindered p-nitrobenzylic chlorides (1) and (2) react with the sodium salts of 2,4,6-trialkylbenzenethiols (3a)-(5a) by the SRN1 reaction to give good yields of the corresponding p-nitrobenzylic aryl sulfides (6)-(10). For example, th
- Look, Kai,Norris, Robert K.
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p. 1077 - 1083
(2007/10/03)
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- A convergent asymmetric synthesis of γ-butenolides
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Addition of aldehydes to the new enantiomerically pure lithiated sulfoxide 4 yielded γ-butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The reaction with ketones was less stereoselective.
- Renard, Marc,Ghosez, Leon
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p. 6237 - 6240
(2007/10/03)
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- Novel synthetic pathways to neutral mixed-ligand iron-sulfur clusters
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The reaction of [Fe(N(SiMe3)2)2] with thiols RSH, elemental sulfur, and neutral ligands L (with sulfur donor atoms, e.g. thiourea derivatives) gives [Fe4S4(SR)2L2] clusters in hi
- Harmjanz,Junghans,Opitz,Bahlmann,Pohl
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p. 1040 - 1048
(2007/10/03)
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- The Preparation, Structure, and Reactions of the Mononuclear Thiolate-Hydride Complexes (R = Bulky Alkyl or Aryl Group, dppe = Ph2PCH2CH2PPh2); X-Ray Structure Determination of cis-i3-2,4,6)(dppe)2>
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Reaction of trans- (dppe = Ph2PCH2CH2PPh2) with the bulky thiols RSH (R = Pri, But, C6H2Me3-2,4,6, C6H2Pri3-2,4,6 or C6H2BrPri2-4,2,6) at reflux in tetrahydrofuran (thf) gives the green hydride complexes .The complex cis-i3-2,4,6)(dppe)2>.0.5C6H5Me has a distorted octahedral structure, with distances: Mo-S 2.402(2), Mo-H 1.61(9), Mo-P 2.380(2)-2.465(2) Angstroem.The 1H hydride resonances of these compounds occur in the range -3.98 to -4.98 p.p.m. (relative to SiMe4) and show fluxionality at room temperature with respect to the phosphorus atoms except for R = C6H2BrPri2-4,2,6.Other spectroscopic properties of the compounds are used as a basis to discuss the mechanism of their formation.The complex i3-2,4,6-)(dppe)2> reacts at 20 deg C with CO or ButNC to give the known compounds and tNC)2(dppe)2>, and with PhSH to give trans-.
- Henderson, Richard A.,Hughes, David L.,Richards, Raymond L.,Shortman, Caroline
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p. 1115 - 1122
(2007/10/02)
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- Rhenium Nitrosyl Complexes with Simple and with Sterically Demanding Aromatic Thiolate Ligands: X-Ray Crystal Structures of *CH2Cl2 and i2-2,6)4(NO)>
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Reaction of with a range of thiophenols under basic conditions gives one of two classes of products depending on the steric requirements of the thiols.A representative member of each class has been characterised by an X-ray crystal
- Blower, Philip J.,Dilworth, Jonathan R.,Hutchinson, John P.,Zubieta, Jon A.
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p. 1533 - 1542
(2007/10/02)
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- Chemistry of Sulfenic Acids. 3. Studies of Sterically Hindered Sulfenic Acids Using Flash Vacuum Pyrolysis
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Flash vacuum pyrolysis (FVP) of sulfoxides containing β-hydrogen atoms affords sulfenic acids (RSOH) in good concentration under conditions where they are stable.The application of this technique to the synthesis and study of sterically hindered sulfenic acids 12a-e is described.The principal or primary reaction of simple sulfenic acids prepared in this manner is dehydration to thiosulfinates 13 (eq 1).Steric inhibition to dehydration (eq 1) appears to only be of importance for 2-methyl-2-propanesulfenic acid (12a) which was trapped in good yield with methyl propiolate to afford 16a. 2,4,6-Tri-tert-butylbenzenesulfenic acid (12e) appears to be destabilized as a consequence of interaction between the SOH and adjacent tert-butyl groups.In the pyrolysis section of the apparatus, 12e decomposes to phenol 21 and aryl radical 22, which reacts further.Thermolysis of sulfoxides generates the sulfenic acids 12a-e in very low concentration at any one time.The products of sulfenic acids generated in this way result from secondary reactions of the corresponding thiosulfinates.
- Davis, Franklin A.,Jenkins, Robert H.,Rizvi, Syed Q. A.,Yocklovich, Steven G.
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p. 3467 - 3474
(2007/10/02)
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- Electrophilic additions to allenes. VI. The role of steric versus electronic effects in the reactions of arenesulphenyl halides with allenes
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The role of steric and electronic effects during the rate and product determining steps for the addition of arenesulphenyl chlorides to 1,3-disubstituted allenes has been briefly examined.Both effects appear to be generally of minimal importance during the rate determinig step.The available rate data indicate the presence of little, if any, build up of positive charge on sulphur.These results are interpreted in terms of an SN2 attack on bivalent sulphur leading to an alkylidenethiiranium ion intermediate.Steric effects are of greater importance in the product determinig step, particularly when the sulphenyl chlorides possess two bulky ortho substituents, as in the case of 2,4,6-triisopropylbenzenesulphenyl chloride.
- Garratt, Dennis G.,Beaulieu, Pierre L.
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p. 2738 - 2744
(2007/10/02)
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