- 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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- Asymmetric Enzymatic Synthesis of Allylic Amines: A Sigmatropic Rearrangement Strategy
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Sigmatropic rearrangements, while rare in biology, offer opportunities for the efficient and selective synthesis of complex chemical motifs. A "P411" serine-ligated variant of cytochrome P450BM3 has been engineered to initiate a sulfimidation/[2,3]-sigmatropic rearrangement sequence in whole E. coli cells, a non-natural function for any enzyme, providing access to enantioenriched, protected allylic amines. Five mutations in the enzyme substantially enhance its activity toward this new function, demonstrating the evolvability of the catalyst toward challenging nitrene transfer reactions. The evolved catalyst additionally performs the highly enantioselective imidation of non-allylic sulfides.
- Prier, Christopher K.,Hyster, Todd K.,Farwell, Christopher C.,Huang, Audrey,Arnold, Frances H.
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supporting information
p. 4711 - 4715
(2016/04/19)
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- Enantioselective nitrene transfer to sulfides catalyzed by a chiral iron complex
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Iron works: Enantioselective nitrene transfer to sulfide was accomplished by a chiral iron(III)/PyBOX catalyst (see scheme). Various sulfimides were thus obtained in high enantioselectivities and yields. Applications of this protocol to the syntheses of enantioenriched sulfoximines and an epoxide were also demonstrated. Copyright
- Wang, Jun,Frings, Marcus,Bolm, Carsten
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supporting information
p. 8661 - 8665
(2013/09/12)
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- Asymmetric sulfimidation with cis-β Ru(salalen)CO2 complexes as catalyst
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Ru(salalen)(CO)2 complexes were found to serve as catalysts for asymmetric sulfimidation under irradiation, and high enantioselectivity (up to 90% ee) was obtained. In addition, the structures of two Ru(salalen)(CO) 2 complexes that
- Fujita, Hidekazu,Uchida, Tatsuya,Irie, Ryo,Katsuki, Tsutomu
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p. 1092 - 1093
(2008/02/10)
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