13159-16-5Relevant academic research and scientific papers
SmI2-H2O-mediated 5-exo/6-exo lactone radical cyclisation cascades
Yalavac, Irem,Lyons, Sarah E.,Webb, Michael R.,Procter, David J.
, p. 12863 - 12866 (2014)
The SmI2-H2O reagent system mediates challenging 5-exo/6-exo lactone radical cascade cyclisations that deliver carbo[5.4.0]bicyclic motifs in a diastereoselective, one-pot process that establish two new carbocyclic rings and four ste
Peroxidase-catalyzed oxidation of 2,4,6-trichlorophenol
Wiese,Chang,Lloyd,Freeman,Samokyszyn
, p. 217 - 222 (1998)
2,4,6-Trichlorophenol (TCP) is an environmental contaminant that is toxic, mutagenic, and carcinogenic. We have investigated peroxidase-catalyzed oxidation of TCP as an alternative pathway of TCP bioactivation using horseradish peroxidase (HRP) as a model peroxidase. TCP was shown to function as a reducing substrate for HRP as evidenced by TCP-dependent, HRP-catalyzed reduction of 5-phenyl-4-penten-1-yl hydroperoxide (PPHP) to its corresponding alcohol. In addition, TCP was shown to undergo hydroperoxide (H2O2, ethyl hydroperoxide, or PPHP)-dependent metabolism as evidenced by electronic absorption spectroscopic analysis of reaction mixtures. A single major product was detected by reverse phase HPLC and was identified as 2,6- dichloro-1,4-benzoquinone (2,6-dichloro-2,5-cyclohexadiene-1,4-dione, CAS no. 697-91-6) on the basis of electronic absorption spectroscopy, mass spectrometry, and cochromatography with synthetic standard. In addition, HRP- catalyzed oxidation of TCP yielded EPR-detectable phenoxyl radical intermediates whose EPR spectrum consisted of a 1:2:1 triplet characterized by proton hyperfine coupling constants a(H(3,5)) = 2.35 gauss. Mechanisms for the hydroperoxide-dependent, HRP-catalyzed oxidation of TCP are proposed that are consistent with these results.
Organocatalytic, Organic Oxidant Promoted, Enamine C?H Oxidation/Cyclopropanation Reaction
Bond?i?, Aleksandra M.,Bond?i?, Bojan P.,D?ambaski, Zdravko,Kokotos, Christoforos G.,Triandafillidi, Ierasia
, p. 4002 - 4008 (2021)
Herein, we demonstrate that organic, single-electron oxidant in the presence of diarylprolinol silylether type catalyst serves as a tool for the transformation of electron-rich enamines to iminium ions. These iminium ions take part in a subsequent Michael-initiated ring-closure (MIRC) reaction with in situ present nucleophile giving rise to overall cyclopropanation reaction of saturated aldehydes. Stereodefined cyclopropanes are obtained in high yields and selectivities. This one-pot transformation represents the additional example of saturated aldehydes being used in the coupled one-pot processes. (Figure presented.).
Intramolecular N-Me and N-H aminoetherification for the synthesis ofN-unprotected 3-amino-O-heterocycles
Paudyal, Mahesh P.,Wang, Mingliang,Siitonen, Juha H.,Hu, Yimin,Yousufuddin, Muhammed,Shen, Hong C.,Falck, John R.,Kürti, László
supporting information, p. 557 - 560 (2021/02/06)
A mild Rh-catalyzed method for synthesis of cyclic unprotected N-Me and N-H 2,3-aminoethers using an olefin aziridination-aziridine ring-opening domino reaction has been developed. The method is readily applicable to the stereocontrolled synthesis of a va
Copper-Catalyzed Enantioselective Hydroalkoxylation of Alkenols for the Synthesis of Cyclic Ethers
Chen, Dake,Berhane, Ilyas A.,Chemler, Sherry R.
supporting information, p. 7409 - 7414 (2020/06/29)
The copper-catalyzed enantioselective intramolecular hydroalkoxylation of unactivated alkenes for the synthesis of tetrahydrofurans, phthalans, isochromans, and morpholines from 4- and 5-alkenols is reported. The substrate scope is complementary to existing enantioselective alkene hydroalkoxylations and is broad with respect to substrate backbone and alkene substitution. The asymmetric induction and isotopic labeling studies support a polar/radical mechanism involving enantioselective oxycupration followed by C-[Cu] homolysis and hydrogen atom transfer. Synthesis of the antifungal insecticide furametpyr was accomplished.
Catalytic Hydroetherification of Unactivated Alkenes Enabled by Proton-Coupled Electron Transfer
Knowles, Robert R.,Metrano, Anthony J.,Tsuchiya, Yuto,Tsui, Elaine
supporting information, p. 11845 - 11849 (2020/05/22)
We report a catalytic, light-driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible-light irradiation in the presence of an IrIII-based photoredox catalyst, a Br?nsted base catalyst, and a hydrogen-atom transfer (HAT) co-catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct homolytic activation of alcohol O?H bonds through a proton-coupled electron-transfer mechanism. This method exhibits a broad substrate scope and high functional-group tolerance, and it accommodates a diverse range of alkene substitution patterns. Results demonstrating the extension of this catalytic system to carboetherification reactions are also presented.
Rhodium-Catalyzed Remote C(sp3)?H Borylation of Silyl Enol Ethers
Li, Jie,Qu, Shuanglin,Zhao, Wanxiang
, p. 2360 - 2364 (2020/01/02)
A rhodium-catalyzed remote C(sp3)?H borylation of silyl enol ethers (SEEs, E/Z mixtures) by alkene isomerization and hydroboration is reported. The reaction exhibits mild reaction conditions and excellent functional-group tolerance. This method is compatible with an array of SEEs, including linear and branched SEEs derived from aldehydes and ketones, and provides direct access to a broad range of structurally diverse 1,n-borylethers in excellent regioselectivities and good yields. These compounds are precursors to various valuable chemicals, such as 1,n-diols and aminoalcohols.
Enantioselective Organocatalytic Enamine C?H Oxidation/Diels- Alder Reaction
D?ambaski, Zdravko,Tzaras, Dimitrios-Ioannis,Lee, Sunggi,Kokotos, Christoforos G.,Bondzic, Bojan P.
supporting information, p. 1792 - 1797 (2019/02/25)
α,β-unsaturated aldehydes have been traditionally used in LUMO lowering asymmetric aminocatalysis (iminium catalysis), while the use of saturated aldehydes as substrates in this type of catalysis has been elusive, until recently. Herein, we demonstrate that organic, single-electron oxidants in the presence of diarylprolinol silylether type catalysts serve as effective tools for the transformation of electron rich enamines to iminium ions which partake in a subsequent Diels-Alder reaction. This enantioselective one-pot transformation represents the first example of saturated aldehydes being used in domino Diels-Alder reaction processes and demonstrates the power of this protocol for construction of stereo-defined chiral compounds and building blocks. (Figure presented.).
Enantioselective Radical Construction of 5-Membered Cyclic Sulfonamides by Metalloradical C-H Amination
Hu, Yang,Lang, Kai,Li, Chaoqun,Gill, Joseph B.,Kim, Isaac,Lu, Hongjian,Fields, Kimberly B.,Marshall, McKenzie,Cheng, Qigan,Cui, Xin,Wojtas, Lukasz,Zhang, X. Peter
supporting information, p. 18160 - 18169 (2019/11/19)
Both arylsulfonyl and alkylsulfonyl azides can be effectively activated by the cobalt(II) complexes of D2-symmetric chiral amidoporphyrins for enantioselective radical 1,5-C-H amination to stereoselectively construct 5-membered cyclic sulfonami
Arene Trifunctionalization with Highly Fused Ring Systems through a Domino Aryne Nucleophilic and Diels–Alder Cascade
He, Jia,Jia, Zizi,Tan, Hongcheng,Luo, Xiaohua,Qiu, Dachuan,Shi, Jiarong,Xu, Hai,Li, Yang
supporting information, p. 18513 - 18518 (2019/11/19)
A convenient and efficient domino aryne process was developed under transition-metal-free conditions to generate a range of tetra- and pentacyclic ring systems. This transformation was realized via a 1,2-benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C?N and two C?C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2-aryne and 2,3-aryne stages. Moreover, in-depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
