21550-01-6Relevant academic research and scientific papers
1,3-Alkyl Transposition in Allylic Alcohols Enabled by Proton-Coupled Electron Transfer
Knowles, Robert R.,Seidler, Gesa,Zhao, Kuo
, p. 20190 - 20195 (2021/08/13)
A method is described for the isomerization of acyclic allylic alcohols into β-functionalized ketones via 1,3-alkyl transposition. This reaction proceeds via light-driven proton-coupled electron transfer (PCET) activation of the O?H bond in the allylic al
Iron-Catalyzed, Iminyl Radical-Triggered Cascade 1,5-Hydrogen Atom Transfer/(5+2) or (5+1) Annulation: Oxime as a Five-Atom Assembling Unit
Chen, Ying-Chun,Du, Fei,Jiang, Kun,Liang, Wu,Ouyang, Qin,Shuai, Li,Wei, Ye,Yang, Jie
, p. 19222 - 19228 (2020/08/25)
By integration of iminyl radical-triggered 1,5-hydrogen atom transfer and (5+2) or (5+1) annulation processes, a series of structurally novel and interesting azepine and spiro-tetrahydropyridine derivatives have been successfully prepared in moderate to good yields. This method utilizes FeCl2 as the catalyst and readily available oximes as five-atom units, while showcasing broad substrate scope and good functional group compatibility. The annulation products can be easily converted into many valuable compounds. Moreover, DFT calculation studies are performed to provide some insights into the possible reaction mechanisms for the (5+2) and (5+1) annulations.
Mn-Enabled Radical-Based Alkyl-Alkyl Cross-Coupling Reaction from 4-Alkyl-1,4-dihydropyridines
Wang, Jie,Pang, Yu-Bo,Tao, Na,Zeng, Run-Sheng,Zhao, Yingsheng
, p. 15315 - 15322 (2019/11/19)
Highly efficient alkylation of β-chloro ketones and their derivatives was achieved by means of domino dehydrochlorination/Mn-enabled radical-based alkyl-alkyl cross-coupling reaction. In situ-generated α,β-unsaturated ketones and their analogues were identified as the reaction intermediates. Known bioactive compounds, such as melperone and azaperone, could be easily prepared from β-chloropropiophenone in two steps.
Iron-Catalyzed Synthesis of Dihydronaphthalenones from Aromatic Oxime Esters
Zhang, Youcan,Yin, Zhiping,Wu, Xiao-Feng
supporting information, p. 3223 - 3227 (2019/05/10)
Herein, a convenient procedure on iron-catalyzed radical-mediated synthesis of dihydronaphthalenones from oxime esters has been developed. By using iron salt as a green and inexpensive catalyst, various α-aryl oxime esters were transformed into the corresponding dihydronaphthalenones in moderate to good yields with high chemo-selectivities. The reaction proceeds via 1,5-hydrogen atom transfer and then intramolecular radical cyclization sequence. (Figure presented.).
Regioselective Vinylation of Remote Unactivated C(sp3)?H Bonds: Access to Complex Fluoroalkylated Alkenes
Wu, Shuo,Wu, Xinxin,Wang, Dongping,Zhu, Chen
supporting information, p. 1499 - 1503 (2019/01/04)
Regioselective incorporation of a particular functional group into aliphatic sites by direct activation of unreactive C?H bonds is of great synthetic value. Despite advances in radical-mediated functionalization of C(sp3)?H bonds by a hydrogen-atom transfer process, the site-selective vinylation of remote C(sp3)?H bonds still remains underexplored. Reported herein is a new protocol for the regioselective vinylation of unactivated C(sp3)?H bonds. The remote C(sp3)?H activation is promoted by a C-centered radical instead of the commonly used N and O radicals. The reaction possesses high product diversity and synthetic efficiency, furnishing a plethora of synthetically valuable E alkenes bearing tri-/di-/mono-fluoromethyl and perfluoroalkyl groups.
Carbonylation of tertiary carbon radicals: synthesis of lactams
Yin, Zhiping,Zhang, Zhuan,Zhang, Youcan,Dixneuf, Pierre H.,Wu, Xiao-Feng
supporting information, p. 4655 - 4658 (2019/05/09)
Herein, we disclose an interesting iron-catalyzed approach for the carbonylation of a tertiary carbon radical. The tertiary carbon radical generated from a 1,5-hydrogen atom transfer can be captured by CO gas smoothly. Various six-membered lactams were constructed chemo-selectively in high yields.
Photoinduced Remote Functionalisations by Iminyl Radical Promoted C?C and C?H Bond Cleavage Cascades
Dauncey, Elizabeth M.,Morcillo, Sara P.,Douglas, James J.,Sheikh, Nadeem S.,Leonori, Daniele
supporting information, p. 744 - 748 (2017/12/13)
A photoinduced cascade strategy leading to a variety of differentially functionalised nitriles and ketones has been developed. These reactions rely on the oxidative generation of iminyl radicals from simple oximes. Radical transposition by C(sp3)?(sp3) and C(sp3)?H bond cleavage gives access to distal carbon radicals that undergo SH2 functionalisations. These mild, visible-light-mediated procedures can be used for remote fluorination, chlorination, and azidation, and were applied to the modification of bioactive and structurally complex molecules.
Hydrogen-borrowing and interrupted-hydrogen-borrowing reactions of ketones and methanol catalyzed by iridium
Shen, Di,Poole, Darren L.,Shotton, Camilla C.,Kornahrens, Anne F.,Healy, Mark P.,Donohoe, Timothy J.
supporting information, p. 1642 - 1645 (2015/02/05)
Reported herein is the use of catalytic [{Ir(cod)Cl}2] to facilitate hydrogen-borrowing reactions of ketone enolates with methanol at 65°C. An oxygen atmosphere accelerates the process, and when combined with the use of a bulky monodentate phosphine ligand, interrupts the catalytic cycle by preventing enone reduction. Subsequent addition of pronucleophiles to the reaction mixture allowed a one-pot methylenation/conjugate addition protocol to be developed, which greatly expands the range of products that can be made by this methodology.
Rhodium-catalyzed ketone methylation using methanol under mild conditions: Formation of α-branched products
Chan, Louis K. M.,Poole, Darren L.,Shen, Di,Healy, Mark P.,Donohoe, Timothy J.
supporting information, p. 761 - 765 (2014/01/23)
The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α-branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one-pot iridium- and rhodium-catalyzed process. Uniquely effective for making branched alkyl products from ketones (see scheme): The scope of the presented reaction includes aromatic and aliphatic ketones and consecutive one-pot double alkylation reactions to provide a convenient route to branched ketones from simple methyl ketones. A brief study into the mechanism of the reaction has given evidence for an aldol-based reaction pathway.
Synthesis of heavily substituted 2-aminopyridines by displacement of a 6-methylsulfinyl group
Teague, Simon J.
supporting information; experimental part, p. 9765 - 9766 (2009/04/06)
(Chemical Equation Presented) 2-Aminopyridines, with a variety of polar 6-substituents, were elaborated by displacement of a methylsulfinyl group from the 6-position of the pyridine ring. The requisite 6-thiomethyl pyridines were synthesized by reaction o
