54367-97-4Relevant academic research and scientific papers
Selective C-C Bond Cleavage of Cycloalkanones by NaNO2/HCl
He, Tianyu,Chen, Dengfeng,Qian, Shencheng,Zheng, Yu,Huang, Shenlin
supporting information, p. 6525 - 6529 (2021/09/02)
A novel selective fragmentation of cycloalkanones by NaNO2/HCl has been established. The C-C bond cleavage reaction proceeds smoothly under mild conditions, selectively affording versatile keto acids or oxime acids. The methodology can streamline the synthesis of valuable chiral molecules and isocoumarins from readily available feedstocks.
Enantioselective Protonation of Silyl Enol Ethers Catalyzed by a Chiral Pentacarboxycyclopentadiene-Based Bronsted Acid
An, Shaoyu,Li, Jun,Li, Pingfan,Yuan, Chao
supporting information, p. 1317 - 1320 (2019/06/19)
The enantioselective protonation of silyl enol ethers was realized in the presence of a pentacarboxycyclopenta-1,3-diene-based chiral Bronsted acid catalyst with water as an achiral proton source to give the corresponding α-aryl ketones in good yields and up to 75percent ee.
Direct Asymmetric α-Hydroxylation of Cyclic α-Branched Ketones through Enol Catalysis
Shevchenko, Grigory A.,Pupo, Gabriele,List, Benjamin
supporting information, p. 49 - 53 (2019/01/04)
Enantiopure α-hydroxy carbonyl compounds are common scaffolds in natural products and pharmaceuticals. Although indirect approaches towards their synthesis are known, direct asymmetric methodologies are scarce. Herein, we report the first direct asymmetric α-hydroxylation of α-branched ketones through enol catalysis, enabling a facile access to valuable α-keto tertiary alcohols. The transformation, characterized by the use of nitrosobenzene as the oxidant and a new chiral phosphoric acid as the catalyst, delivers a good scope and excellent enantioselectivities.
p-Toluenesulfonic acid catalysed fluorination of α-branched ketones for the construction of fluorinated quaternary carbon centres
Tang, Shi-Zhong,Bian, Hong-Li,Zhan, Zong-Song,Chen, Meng-En,Lv, Jian-Wei,Xie, Shaolei,Zhang, Fu-Min
supporting information, p. 12377 - 12380 (2018/11/30)
A p-toluenesulfonic acid catalyzed fluorination of α-branched ketones for the construction of fluorinated quaternary carbon centers has been developed, featuring a broad substrate scope, environmentally benign reaction conditions, and operational simplicity.
Chiral bronsted acid from a cationic gold(I) complex: Catalytic enantioselective protonation of silyl enol ethers of ketones
Cheon, Cheol Hong,Kanno, Osamu,Toste, F. Dean
supporting information; experimental part, p. 13248 - 13251 (2011/10/10)
A chiral Bronsted acid has been developed from a cationic gold(I) disphosphine complex in the presence of alcoholic solvent and applied to the enantioselective protonation reaction of silyl enol ethers of ketones. Various optically active cyclic ketones were obtained in excellent yields and high enantioselectivities, including cyclic ketones bearing aliphatic substrates at the α-position. Furthermore, the application of this Bronsted acid was extended to the first Bronsted acid-catalyzed enantioselective protonation reaction of silyl enol ethers of acyclic substrates, regardless of their E/Z ratio.
Chiral sulfinamide/achiral sulfonic acid cocatalyzed enantioselective protonation of enol silanes
Beck, Elizabeth M.,Hyde, Alan M.,Jacobsen, Eric N.
supporting information; experimental part, p. 4260 - 4263 (2011/10/08)
The application of chiral sulfinamides and achiral sulfonic acids as a cocatalyst system for enantioselective protonation reactions is described. Structurally simple, easily accessible sulfinamides were found to induce moderate-to-high ee's in the formation of 2-aryl-substituted cycloalkanones from the corresponding trimethylsilyl enol ethers.
Development of a new Lewis base-tolerant chiral LBA and its application to catalytic asymmetric protonation reaction
Cheon, Cheol Hong,Imahori, Tatsushi,Yamamoto, Hisashi
supporting information; experimental part, p. 6980 - 6982 (2010/11/02)
A new Lewis base-tolerant LBA (Lewis Acid Assisted Bronsted Acid) derived from La(OTf)3 and (S)-HOP has been developed as a new chiral Bronsted acid. This acid has been successfully applied as a catalyst to asymmetric protonation reactions of silyl enol ethers of 2-substituted cyclic ketones.
A bronsted acid catalyst for the enantioselective protonation reaction
Cheol, Hong Cheon,Yamamoto, Hisashi
supporting information; body text, p. 9246 - 9247 (2009/02/02)
A highly reactive and robust chiral Bronsted acid catalyst, chiral N-triflyl thiophosphoramide, was developed. The first metal-free Bronsted acid catalyzed enantioselective protonation reaction of silyl enol ethers was demonstrated using this chiral Bronsted acid catalyst. The catalyst loading could be reduced to 0.05 mol % without any deleterious effect on the enantioselectivity. Copyright
A convenient synthesis of 2-naphthylcyclopentanones and 2-naphthylcyclohexanones from 1-naphthylcycloalkenes
Gora, Maciej,Luczynski, Michal K.,Sepiol, Janusz J.
, p. 1625 - 1630 (2007/10/03)
The oxidation of naphthylcycloalkenes with hydrogen peroxide or MCPBA followed by acid catalyzed rearrangement of diol (epoxide), afforded a series of naphthylcycloalkanones in a very simple manner. The conditions allow preparation of naphthylcycloalkanones on a multigram scale. Georg Thieme Verlag Stuttgart.
Palladium-catalyzed intramolecular hydroalkylation of alkenyl- β-keto esters, α-aryl ketones, and alkyl ketones in the presence of Me 3SiCl or HCI
Han, Xiaoqing,Wang, Xiang,Pei, Tao,Widenhoefer, Ross A.
, p. 6333 - 6342 (2007/10/03)
Reaction of 3-butenyl β-keto esters or 3-butenyl α-aryl ketones with a catalytic amount of [PdCl2(CH3CN)2] (2) and a stoichiometric amount of Me3SiCl or Me3SiCl/ CuCl2 in dioxane at 25-70°C formed 2-substituted cyclohexanones in good yield with high regioselectivity. This protocol tolerated a number of ester and aryl groups and tolerated substitution at the allylic, enolic, and cis and trans terminal olefinic positions. In situ NMR experiments indicated that the chlorosilane was not directly involved in palladium-catalyzed hydroalkylation, but rather served as a source of HCl, which presumably catalyzes enolization of the ketone. Identification of HCl as the active promoter of palladium-catalyzed hydroalkylation led to the development of an effective protocol for the hydroalkylation of alkyl 3-butenyl ketones that employed sub-stoichiometric amounts of 2, HCl, and CuCl2 in a sealed tube at 70°C.
