- Cationic PCP iridaepoxide and carbene complexes for facile water elimination and activation processes
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Iridaepoxide dihydride complexes of a PCP ligand bearing benzo[b]thiophene linkers are synthesized through ligand coopertive N2O and H2 activations. These neutral complexes also eliminate water at elevated temperatures to form the corresponding PCcarbeneP complexes which results in the formal hydrogenation of N2O to water. The synthesis of cationic iridaepoxide dihydride complexes are reported herein where the room temperature elimination of water is observed when a donating solvent is used. This supports a previously proposed mechanism for this water elimination where hydrides cis to the epoxide are required. Ir(i) and Ir(iii) cationic PCcarbeneP complexes are also synthesized through protonation and through O-H oxidation additions of water and phenol.
- Doyle, Lauren E.,Piers, Warren E.,Bi, David W.
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- A Dicopper Nitrenoid by Oxidation of a CuICuICore: Synthesis, Electronic Structure, and Reactivity
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A dicopper nitrenoid complex was prepared by formal oxidative addition of the nitrenoid fragment to a dicopper(I) center by reaction with the iminoiodinane PhINTs (Ts = tosylate). This nitrenoid complex, (DPFN)Cu2(μ-NTs)[NTf2]2 (DPFN = 2,7-bis(fluorodi(2-pyridyl)methyl)-1,8-naphthyridine), is a powerful H atom abstractor that reacts with a range of strong C-H bonds to form a mixed-valence Cu(I)/Cu(II) μ-NHTs amido complex in the first example of a clean H atom transfer to a dicopper nitrenoid core. In line with this reactivity, DFT calculations reveal that the nitrenoid is best described as an iminyl (NR radical anion) complex. The nitrenoid was trapped by the addition of water to form a mixed-donor hydroxo/amido dicopper(II) complex, which was independently obtained by reaction of a Cu2(μ-OH)2 complex with an amine through a protonolysis pathway. This mixed-donor complex is an analogue for the proposed intermediate in copper-catalyzed Chan-Evans-Lam coupling, which proceeds via C-X (X = N or O) bond formation. Treatment of the dicopper(II) mixed donor complex with MgPh2(THF)2 resulted in generation of a mixture that includes both phenol and a previously reported dicopper(I) bridging phenyl complex, illustrating that both reduction of dicopper(II) to dicopper(I) and concomitant C-X bond formation are feasible.
- Desnoyer, Addison N.,Nicolay, Amélie,Ziegler, Micah S.,Lakshmi,Cundari, Thomas R.,Tilley, T. Don
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supporting information
p. 7135 - 7143
(2021/05/31)
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- Pyridinyl Amide Ion Pairs as Lewis Base Organocatalysts
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Pyridinyl amide ion pairs carrying various electron-withdrawing substituents were synthesized with selected ammonium or phosphonium counterions. Compared to neutral pyridine-based organocatalysts, these new ion pair Lewis bases display superior catalytic
- Amp?ler, Torsten,Helberg, Julian,Zipse, Hendrik
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p. 5390 - 5402
(2020/05/19)
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- Calcium-catalyzed direct amination of π-activated alcohols
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A calcium-catalyzed direct amination of π-activated alcohols with different nitrogen nucleophiles under very mild reaction conditions is presented. The high reactivity of the calcium catalyst allows for an efficient conversion of secondary and tertiary benzylic and allylic as well as tertiary propargylic alcohols. Nitrogen nucleophiles such as carbamates, tosylamides and anilines are readily alkylated at room temperature.
- Haubenreisser, Stefan,Niggemann, Meike
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body text
p. 469 - 474
(2011/04/16)
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- A simple access to metallic or onium bistrifluoromethanesulfonimide salts
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Numerous salts of the (CF3SO2)2N- anion, called TFSI, were prepared according to an original one-pot procedure. First, N-benzyl trifluoromethanesulfonimide (N-benzyl triflimide) was treated with ethanol to form
- Arvai, Roman,Toulgoat, Fabien,Langlois, Bernard R.,Sanchez, Jean-Yves,Médebielle, Maurice
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experimental part
p. 5361 - 5368
(2009/12/01)
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