33599-17-6Relevant academic research and scientific papers
A diiron(III,IV) imido species very active in nitrene-transfer reactions
Goure, Eric,Avenier, Frederic,Dubourdeaux, Patrick,Seneque, Olivier,Albrieux, Florian,Lebrun, Colette,Clemancey, Martin,Maldivi, Pascale,Latour, Jean-Marc
, p. 1580 - 1584 (2014)
Metal-catalyzed nitrene transfer reactions arouse intense interest as clean and efficient procedures for amine synthesis. Efficient Rh- and Ru-based catalysts exist but Fe alternatives are actively pursued. However, reactive iron imido species can be very short-lived and getting evidence of their occurrence in efficient nitrene-transfer reactions is an important challenge. We recently reported that a diiron(III,II) complex is a very efficient nitrene-transfer catalyst to various substrates. We describe herein how, by combining desorption electrospray ionization mass spectrometry, quantitative chemical quench experiments, and DFT calculations, we obtained conclusive evidence for the occurrence of an {FeIIIFeIV=NTosyl} intermediate that is very active in H-abstraction and nitrene-transfer reactions. DFT calculations revealed a strong radical character of the tosyl nitrogen atom in very low-lying electronic configurations of the FeIV ion which are likely to confer its high reactivity. Nitrene transfer: An FeIIIFeIV imido intermediate is identified in nitrene-transfer reactions by desorption electrospray ionization mass spectrometry (DESI-MS). DFT calculations show that low-lying FeIIIFeIII-.N-tosyl configurations play a major role in the high reactivity of the intermediate. Copyright
Electronic effect, steric hindrance, and anchimeric assistance in oxidation of sulphides. Neighbouring-group participation through Sulphur-oxygen nonbonded interaction
Ruff, Ferenc,Kucsman, Arpad
, p. 1123 - 1128 (2007/10/02)
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.
