19311-91-2Relevant academic research and scientific papers
Chemo- and Regioselective Anionic Fries Rearrangement Promoted by Lithium Amides under Aerobic Conditions in Sustainable Reaction Media
Antenucci, Achille,Blangetti, Marco,Bolzoni, Paola,De Nardi, Federica,Ghinato, Simone,Prandi, Cristina
, (2022/05/27)
A straightforward and efficient protocol to promote the metalation/anionic Fries rearrangements of O-aryl carbamates, using for the first time a lithium amide as metalating agent under aerobic/ambient-friendly reaction conditions, is reported. This approach enables the sustainable preparation of salicylamide derivatives with high levels of chemoselectivity within ultrafast reaction times, working at room temperature in the presence of air/moisture, and using environmentally responsible cyclopentyl methyl ether as a solvent. Furthermore, the regioselective manipulation of O-2-tolyl carbamates has been accomplished using interchangeably alkyllithiums or lithium amides, with an unexpected beneficial contribution from the employment of biorenewable protic eutectic mixtures as non-innocent reaction media.
Rhoda-Electrocatalyzed Bimetallic C?H Oxygenation by Weak O-Coordination
Tan, Xuefeng,Massignan, Leonardo,Hou, Xiaoyan,Frey, Johanna,Oliveira, Jo?o C. A.,Hussain, Masoom Nasiha,Ackermann, Lutz
, p. 13264 - 13270 (2021/05/06)
Rhodium-electrocatalyzed arene C?H oxygenation by weakly O-coordinating amides and ketones have been established by bimetallic electrocatalysis. Likewise, diverse dihydrooxazinones were selectively accessed by the judicious choice of current, enabling twofold C?H functionalization. Detailed mechanistic studies by experiment, mass spectroscopy and cyclovoltammetric analysis provided support for an unprecedented electrooxidation-induced C?H activation by a bimetallic rhodium catalysis manifold.
Aryl Carbamates: Mechanisms of Orthosodiations and Snieckus-Fries Rearrangements
Ma, Yun,Woltornist, Ryan A.,Algera, Russell F.,Collum, David B.
, p. 9051 - 9057 (2019/08/15)
Aryl carbamates are orthometalated by sodium diisopropylamide (NaDA) in tetrahydrofuran. The resulting arylsodiums undergo Snieckus-Fries rearrangement to give orthoacylated phenols in good yield. The intermediate arylsodiums and resulting orthoacylated phenolates are suggested to be monomeric. The rate-limiting step in the two-step sequence depends on the steric demands of the carbamoyl moiety and the substituents in the meta position of the arene. Rate studies reveal a dominant disolvated-monomer-based orthometalation followed by a di- or trisolvated arylsodium monomer-based rearrangement. Kinetic evidence of a NaDA-catalyzed Snieckus-Fries rearrangement suggests the intermediacy of mixed trimers. Competitive halide eliminations to form benzyne are also discussed.
Directed ortho-Metalation of O-Aryl N,N-Dialkylcarbamates: Methodology, Anionic ortho-Fries Rearrangement, and Lateral Metalation
Miah, M. A. Jalil,Sibi, Mukund P.,Chattopadhyay,Familoni, Oluwole B.,Snieckus, Victor
, p. 440 - 446 (2017/12/15)
The directed ortho-lithiation reactions of O-aryl N,N-dialkylcarbamates as well as O-1-naphthyl and O-2-naphthyl N,N-dialkylcarbamates with sec-butyllithium/tetramethylethylenediamine (sBuLi/TMEDA) followed by quenching with various electrophiles afford a range of polysubstituted aromatic compounds. If the solutions of the ortho-lithiated carbamates are warmed to room temperature without the addition of external electrophiles, salicylamide and 1- and 2-hydroxynaphthamide derivatives are formed through anionic ortho-Fries rearrangements. The relative stabilities and reactivities of different O-aryl N,N-dialkylcarbamates were investigated. The lateral metalation of 2-tolyl carbamates with lithium diisopropylamide (LDA) provides a route to benzo[b]furan-2(3H)-ones. Previously reported results are used in a comparison of seven O-based directed metalation groups in reactions with several electrophiles. The described methodology is useful for the preparation of 1,2,3-substituted aromatic compounds.
Submillisecond organic synthesis: Outpacing Fries rearrangement through microfluidic rapid mixing
Kim, Heejin,Min, Kyoung-Ik,Inoue, Keita,Im, Do Jin,Kim, Dong-Pyo,Yoshida, Jun-Ichi
, p. 691 - 694 (2016/05/19)
In chemical synthesis, rapid intramolecular rearrangements often foil attempts at site-selective bimolecular functionalization.We developed a microfluidic technique that outpaces the very rapid anionic Fries rearrangement to chemoselectively functionalize iodophenyl carbamates at the ortho position. Central to the technique is a chip microreactor of our design, which can deliver a reaction time in the submillisecond range even at cryogenic temperatures.The microreactorwas applied to the synthesis of afesal, a bioactive molecule exhibiting anthelmintic activity, to demonstrate its potential for practical synthesis and production.
Direct Hydroxylation and Amination of Arenes via Deprotonative Cupration
Tezuka, Noriyuki,Shimojo, Kohei,Hirano, Keiichi,Komagawa, Shinsuke,Yoshida, Kengo,Wang, Chao,Miyamoto, Kazunori,Saito, Tatsuo,Takita, Ryo,Uchiyama, Masanobu
supporting information, p. 9166 - 9171 (2016/08/05)
Deprotonative directed ortho cupration of aromatic/heteroaromatic C-H bond and subsequent oxidation with t-BuOOH furnished functionalized phenols in high yields with high regio- and chemoselectivity. DFT calculations revealed that this hydroxylation reaction proceeds via a copper (I → III → I) redox mechanism. Application of this reaction to aromatic C-H amination using BnONH2 efficiently afforded the corresponding primary anilines. These reactions show broad scope and good functional group compatibility. Catalytic versions of these transformations are also demonstrated.
Copper-catalyzed cross dehydrogenative coupling of N,N-disubstituted formamides and phenols: A direct access to carbamates
Ali, Wajid,Rout, Saroj K.,Guin, Srimanta,Modi, Anju,Banerjee, Arghya,Patel, Bhisma K.
, p. 515 - 522 (2015/03/05)
An efficient copper-catalyzed protocol has been developed for the synthesis of carbamates from dialkylformamides and phenols possessing directing groups such as benzothiazole, quinoline and formyl at the ortho-position. In this chelation assisted approach, C-O bond formation takes place via a cross dehydrogenative coupling (CDC) between the formyl C-H of dialkylformamide and phenolic O-H in the presence of copper(II)acetate/aqueous tertbutyl hydroperoxide. Under identical reaction conditions, salicylic acid derivatives underwent amidation with the carboxylic group rather than formamidation of the phenolic OH. The use of a cheap and environmentally benign catalyst along with the tolerance of a wide range of functional groups makes this an easy, phosgene-free route to carbamates. carbamates; C-H activation; copper catalysis; cross dehyrogenative coupling
Lithiation of a silyl ether: Formation of an ortho-fries hydroxyketone
Lo, Hong-Jay,Lin, Chin-Yin,Tseng, Mei-Chun,Chein, Rong-Jie
supporting information, p. 9026 - 9029 (2014/09/17)
A hydroxy-directed alkylation of an N,N-diethylarylamide using CIPE-assisted α-silyl carbanions (CIPE=complex-induced proximity effect) has been developed using a simple reagent combination of LDA (lithium diisopropylamide) and chlorosilane. A study of the mechanism, and the application of the procedure to an anionic Snieckus-Fries rearrangement for a highly efficient synthesis of the potent phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, are reported.
Novel synthesis of a new surfactant 4-((4-bromophenyl)(dodecyl)amino)-4- oxobutanoic acid containing a benzene ring using a copper catalyst cross-coupling reaction and its properties
Chen, Minggui,Hu, Xinqi,Fu, Meilong
, p. 581 - 585 (2013/07/26)
A new surfactant 4-((4-bromophenyl)(dodecyl)amino)-4-oxobutanoic acid with a benzene spacer was synthesized via a novel copper catalyzed cross-coupling reaction. Its structure was confirmed by FTIR, 1H-NMR, 13C-NMR and HRMS; its purity was checked by HPLC. Dynamic light scattering and an atomic force microscope showed that it forms an unusual large-diameter premicellar aggregation below the CMC.
Ortho-and para-selective ruthenium-catalyzed C(sp2)-H oxygenations of phenol derivatives
Liu, Weiping,Ackermann, Lutz
supporting information, p. 3484 - 3486 (2013/07/26)
Versatile ruthenium catalysts allowed for efficient direct oxygenations of aryl carbamates under remarkably mild reaction conditions. In addition to chelation-assisted C-H activation, the optimized ruthenium catalyst proved amenable to para-selective hydroxylations of anisoles without Lewis basic directing groups.
