- Dehydrogenative α-oxygenation of ethers with an iron catalyst
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Selective α-oxidation of ethers under aerobic conditions is a long-pursued transformation; however, a green and efficient catalytic version of this reaction remains challenging. Herein, we report a new family of iron catalysts capable of promoting chemoselective α-oxidation of a range of ethers with excellent mass balance and high turnover numbers under 1 atm of O2 with no need for any additives. Unlike metalloenzymes and related biomimetics, the catalyst produces H2 as the only byproduct. Mechanistic investigations provide evidence for an unexpected two-step reaction pathway, which involves dehydrogenative incorporation of O2 into the ether to give a peroxobisether intermediate followed by cleavage of the peroxy bond to form two ester molecules, releasing stoichiometric H2 gas in each step. The operational simplicity and environmental friendliness of this methodology affords a useful alternative for performing oxidation, while the unique ability of the catalyst in oxygenating a substrate via dehydrogenation points to a new direction for understanding metalloenzymes and designing new biomimetic catalysts.
- Gonzalez-De-Castro, Angela,Robertson, Craig M.,Xiao, Jianliang
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p. 8350 - 8360
(2014/06/24)
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- Preparation of a storable zinc carbenoid species and its application in cyclopropanation, chain extension, and [2,3]-sigmatropic rearrangement reactions
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(Chemical Equation Presented) The formation of a new phosphate carbenoid (n-BuO)2P(O)OZnCH2I and its application in organozinc-mediated reactions is described. This carbenoid undergoes very slow degradation in solution and can be stored for several weeks at -20 °C. Its reactivity was tested with many representative alkenes and was determined to be a powerful cyclopropanating reagent, giving the corresponding cyclopropanes in 72-99% yield. The use of this carbenoid in the chain extension of 1,3-diketones and [2,3]-sigmatropic rearrangement reactions is also described. 2010 American Chemical Society.
- Voituriez, Arnaud,Zimmer, Lucie E.,Charette, Andre B.
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experimental part
p. 1244 - 1250
(2010/04/26)
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- A Catalytic Enantioselective Reaction Using a C2-Symmetric Disulfonamide as a Chiral Ligand: Simmons-Smith Cyclopropanation of Allylic Alcohols by the Et2Zn-CH2I2-Disulfonamide System
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A catalytic and enantioselective Simmons-Smith cyclopropanation of an allylic alcohol was developed by the reaction of an allylic alcohol with Et2Zn and CH2I2 in the presence of a catalytic amount of chiral disulfonamide 4.
- Takahashi, Hideyo,Yoshioka, Masato,Shibasaki, Masakatsu,Ohno, Masaji,Imai, Nobuyuki,Kobayashi, Susumu
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p. 12013 - 12026
(2007/10/02)
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