- Catalytic Chemoselective Sulfimidation with an Electrophilic [CoIII(TAML)]?-Nitrene Radical Complex**
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The cobalt species PPh4[CoIII(TAMLred)] is a competent and stable catalyst for the sulfimidation of (aryl)(alkyl)-substituted sulfides with iminoiodinanes, reaching turnover numbers up to 900 and turnover frequencies of 640 min?1 under mild and aerobic conditions. The sulfimidation proceeds in a highly chemoselective manner, even in the presence of alkenes or weak C?H bonds, as supported by inter- and intramolecular competition experiments. Functionalization of the sulfide substituent with various electron-donating and electron-withdrawing arenes and several alkyl, benzyl and vinyl fragments is tolerated, with up to quantitative product yields. Sulfimidation of phenyl allyl sulfide led to [2,3]-sigmatropic rearrangement of the initially formed sulfimide species to afford the corresponding N-allyl-S-phenyl-thiohydroxylamines as attractive products. Mechanistic studies suggest that the actual nitrene transfer to the sulfide proceeds via (previously characterized) electrophilic nitrene radical intermediates that afford the sulfimide products via electronically asynchronous transition states, in which SET from the sulfide to the nitrene radical complex precedes N?S bond formation in a single concerted process.
- van Leest, Nicolaas P.,van der Vlugt, Jarl Ivar,de Bruin, Bas
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supporting information
p. 371 - 378
(2020/12/01)
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- Sulfonylimino group transfer reaction using imino-λ3-iodanes with I2 as catalyst under metal-free conditions
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A new practical procedure of imination for sulfide has been developed. The treatment of (N-tosylimino)-phenyl-λ3-iodane, PhINTs, with various sulfides in the presence of a catalytic amount of I2 under metal-free conditions affords the corresponding N-tosylsulfilimine compounds with moderate to good yields. This facile transfer procedure of the sulfonylimino group can also be applied to triphenylphosphine to produce the respective iminotriphenylphosphoranes in high yields. According to the reaction mechanism studies, the process of imination from (N-tosylimino)-phenyl-λ3-iodane to sulfide under the conditions may involve radical steps within the reaction mechanism.
- Yoshimura, Akira,Makitalo, Cody L.,Jarvi, Melissa E.,Shea, Michael T.,Postnikov, Pavel S.,Rohde, Gregory T.,Zhdankin, Viktor V.,Saito, Akio,Yusubov, Mekhman S.
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- Electronic effect, steric hindrance, and anchimeric assistance in oxidation of sulphides. Neighbouring-group participation through Sulphur-oxygen nonbonded interaction
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Using a set of sulphides o- and p-XC6H4SMe, the electronic effect, steric hindrance, and anchimeric assistance for electrophilic Cl+ addition by TsNHCI and O-transfer by NalO4 were investigated by a kinetic method. The steric effect and anchimeric assistance of the ortho-substituents were evaluated by comparing the reactivity of ortho- and para-substituted compounds (K = ko/kp). For neighbouringgroup activity the following order was obtained: CH2OH ~ CH2OMe ~ CH2CO2Me CH2CO2H ~ CH2NMe2 CH2C02 - ~ CHO CO2Me ~ CO2H COMe ~ CONH2 C02- Reaction rates show that the anchimeric assistance is governed by an S mellip; 0 or S ... N close contact developed in the transition state between oppositely polarized heteroatoms. Factors controlling neighbouringgroup participation through attractive non-bonded interactions are discussed.
- Ruff, Ferenc,Kucsman, Arpad
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p. 1123 - 1128
(2007/10/02)
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