- Synthesis of ortho-phenolic sulfilimines via an intermolecular sulfur atom transfer cascade reaction
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To expand the toolbox for the synthesis of ortho-phenolic sulfilimines, sigmatropic rearrangements were introduced to the field of sulfilimine chemistry. Herein we report a N-H sulfenylation/[2,3]-sigmatropic rearrangement cascade reaction. This mild reaction enables commercially available thiols to serve as the sulfenylation reagent and generates water as the sole byproduct. Moreover, the reaction has a wide substrate scope and can be conducted on a gram scale with excellent reaction efficiency.
- Ren, Yan,Song, Yinan,Xiong, Feng,Xu, Shaojian,Zhang, Linxing,Zhang, Xinhao,Zuo, Yingying
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supporting information
p. 3799 - 3803
(2020/06/08)
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- Catalytic Alkene Difunctionalization via Imidate Radicals
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The first catalytic strategy to harness imidate radicals has been developed. This approach enables alkene difunctionalization of allyl alcohols by photocatalytic reduction of their oxime imidates. The ensuing imidate radicals undergo consecutive intra- and intermolecular reactions to afford (i) hydroamination, (ii) aminoalkylation, or (iii) aminoarylation, via three distinct radical mechanisms. The broad scope and utility of this catalytic method for imidate radical reactivity is presented, along with comparisons to other N-centered radicals and complementary, closed-shell imidate pathways.
- Nakafuku, Kohki M.,Fosu, Stacy C.,Nagib, David A.
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supporting information
p. 11202 - 11205
(2018/09/12)
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- An Environmentally Sustainable Mechanochemical Route to Hydroxamic Acid Derivatives
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An operationally simple, and cost efficient conversion of carboxylic acids into hydroxamic acid derivatives via a high-energy mechanochemical activation is presented. This ball milling methodology was applied to a wide variety of carboxylic acids dramatically improving purification issues associated with this class of molecules, which still remain one of the main bottlenecks of classical methodologies. (Figure presented.).
- Mocci, Rita,De Luca, Lidia,Delogu, Francesco,Porcheddu, Andrea
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p. 3135 - 3144
(2016/10/09)
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- Rhodium(iii)-catalyzed C-H activation/[4+3] annulation of N-phenoxyacetamides and α,β-unsaturated aldehydes: An efficient route to 1,2-oxazepines at room temperature
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An efficient Rh(iii)-catalyzed coupling reaction of N-phenoxyacetamides with α,β-unsaturated aldehydes to give 1,2-oxazepines via C-H activation/[4+3] annulation has been developed. This transformation does not require oxidants and features C-C/C-N bond formation to yield seven-membered oxazepine rings at room temperature. Further derivation of 1,2-oxazepines leads to important chroman derivatives. This journal is
- Duan, Pingping,Lan, Xia,Chen, Ying,Qian, Shao-Song,Li, Jie Jack,Lu, Liang,Lu, Yanbo,Chen, Bo,Hong, Mei,Zhao, Jing
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supporting information
p. 12135 - 12138
(2014/12/11)
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- Rhodium(III)-catalyzed redox-neutral coupling of N-phenoxyacetamides and alkynes with tunable selectivity
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Give it a tweak: A novel oxidizing directing group was developed for a rhodium(III)-catalyzed C-H functionalization of N-phenoxyacetamides with alkynes. A small change in the reaction conditions leads to either ortho-hydroxyphenyl-substituted enamides or cyclization to deliver benzofurans with high selectivity (see scheme; Cp=C5Me5). Copyright
- Liu, Guixia,Shen, Yangyang,Zhou, Zhi,Lu, Xiyan
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p. 6033 - 6037
(2013/07/19)
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- Rhodium(III)-catalyzed heterocycle synthesis using an internal oxidant: Improved reactivity and mechanistic studies
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Directing groups that can act as internal oxidants have recently been shown to be beneficial in metal-catalyzed heterocycle syntheses that undergo C-H functionalization. Pursuant to the rhodium(III)-catalyzed redox-neutral isoquinolone synthesis that we recently reported, we present in this article the development of a more reactive internal oxidant/directing group that can promote the formation of a wide variety of isoquinolones at room temperature while employing low catalyst loadings (0.5 mol %). In contrast to previously reported oxidative rhodium(III)-catalyzed heterocycle syntheses, the new conditions allow for the first time the use of terminal alkynes. Also, it is shown that the use of alkenes, including ethylene, instead of alkynes leads to the room temperature formation of 3,4-dihydroisoquinolones. Mechanistic investigations of this new system point to a change in the turnover limiting step of the catalytic cycle relative to the previously reported conditions. Concerted metalation-deprotonation (CMD) is now proposed to be the turnover limiting step. In addition, DFT calculations conducted on this system agree with a stepwise C-N bond reductive elimination/N-O bond oxidative addition mechanism to afford the desired heterocycle. Concepts highlighted by the calculations were found to be consistent with experimental results.
- Guimond, Nicolas,Gorelsky, Serge I.,Fagnou, Keith
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supporting information; experimental part
p. 6449 - 6457
(2011/06/16)
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- N-amidation by copper-mediated cross-coupling of organostannanes or boronic acids with O-acetyl hydroxamic acids
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(Chemical Equation Presented) A general nonoxidative N-amidation of organostannanes and boronic acids has been developed. Under nonbasic conditions a wide variety of aryl, alkenyl, and heteroaryl organostannanes and boronic acids couple efficiently with O-acetyl hydroxamic acids in the presence of Cu(I) sources.
- Zhang, Zhihui,Yu, Ying,Liebeskind, Lanny S.
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supporting information; experimental part
p. 3005 - 3008
(2009/04/18)
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- Thermolyses of O-Phenyl Oxime Ethers. A New Source of Iminyl Radicals and a New Source of Aryloxyl Radicals
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Six O-phenyl ketoxime ethers, RR′C=NOPh 1-6, with RR′= diaryl, dialkyl, and arylalkyl, together with N-phenoxybenzimidic acid phenyl ether, PhO(Ph)C=NOPh, 7, have been shown to thermolyze at moderate temperatures with "clean" N-O bond homolyses to yield iminyl and phenoxyl radicals, RR′C=N. and PhO.. Since 1-6 can be synthesized at room temperature, these compounds provide a new and potentially useful source of iminyls for syntheses. The iminyl from 7 undergoes a competition between β-scission, to PhCN and PhO., and cyclization to an oxazole. Rate constants, 106 k/s-1, at 90 °C for 1-6 range from 4.2 (RR′ = 9-fluorenyl) to 180 (RR′ = 9-bicyclononanyl), and that for 7 is 0.61. The estimated activation enthalpies for N-O bond scission are in satisfactory agreement with the results of DFT calculations of N-O bond dissociation enthalpies, BDEs, and represent the first thermochemical data for any reaction yielding iminyl radicals. The small range in k (N-O homolyses) is consistent with the known σ structure of these radicals, and the variations in k and N-O BDEs with changes in RR′ are rationalized in terms of iminyl radical stabilization by hyperconjugation: RR′C=N . ? R.R′C≡N. Calculated N-H BDEs in the corresponding RR′C= NH are also presented.
- Blake, Jessie A.,Pratt, Derek A.,Lin, Shuqiong,Walton, John C.,Mulder, Peter,Ingold
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p. 3112 - 3120
(2007/10/03)
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- AlCl3-mediated migration of benzamido group of N-phenoxybenzamide derivatives to the phenyl group
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AlCl3-mediated decomposition of N-phenoxybenzamide derivatives in dichloromethane mainly leads to regioselective intramolecular migration of benzamido group from the oxygen to the ortho position of the phenyl group via electron-deficient nitrogen intermediates.
- Miyazawa, Etsuko,Sakamoto, Takeshi,Kikugawa, Yasuo
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