128816-77-3Relevant articles and documents
Highly enantioselective construction of CF3-bearing all-carbon quaternary stereocenters: Hiral spiro-fused bisoxazoline ligands with 1,1′-binaphthyl sidearm for asymmetric Michael-type Friedel-Crafts reaction
Bao, Robert Li-Yuan,Fu, Kang,Shi, Lei
supporting information, (2021/11/27)
A novel class of chiral spiro-fused bisoxazoline ligands possessing a deep chiral pocket was prepared. The developed ligands have been employed in the nickel-catalyzed highly enantioselective Michael-type Friedel-Crafts reaction, affording the products bearing a trifluoromethylated all-carbon quaternary stereocenter with moderate to excellent yields (up to 99%) and good to excellent enantioselectivies (up to > 99.9% ee). Moreover, a proposed model of chiral pocket revealed that the attack of indole from the Re-face of β-CF3-β-disubstituted nitroalkene was favorable.
Synthesis of Unsymmetric Triarylmethanes Bearing CF 3-Substituted All-Carbon Quaternary Stereocenters: 1,6-Arylation of δ-Trifluo romethyl Substituted para -Quinone Methides
Ma, Yingang,Pang, Jingxiang,Pan, Xiaoguang,Ma, Shutao,Liu, Xigong,Liu, Lei
supporting information, p. 1619 - 1622 (2020/09/15)
Pre-synthesized δ-CF 3-δ-aryl-disubstituted para -quinone methides bearing δ-substituents were identified as isolable and storable substrates for 1,6-arylation reactions. A broad range of electron-rich arenes and heteroarenes participated in the arylation process, furnishing a wide array of unsymmetrical CF 3-substituted triarylmethanes in high efficiency. The mild and expeditious protocol exhibited broad scopes of both arene and para -quinone methide components.
Gas/Liquid-Phase Micro-Flow Trifluoromethylation using Fluoroform: Trifluoromethylation of Aldehydes, Ketones, Chalcones, and N-Sulfinylimines
Hirano, Kazuki,Gondo, Satoshi,Punna, Nagender,Tokunaga, Etsuko,Shibata, Norio
, p. 406 - 410 (2019/02/13)
A micro-flow nucleophilic trifluoromethylation of carbonyl compounds using gaseous fluoroform was developed. This method also allows the first micro-flow transformation of N-sulfinylimines into trifluoromethyl amines with excellent diastereoselectivity. To demonstrate the synthetic utility of this micro-flow synthesis, the formal micro-flow synthesis of Efavirenz is described.
Oxidation of α-trifluoromethyl and non-fluorinated alcohols: Via the merger of oxoammonium cations and photoredox catalysis
Pistritto, Vincent A.,Paolillo, Joshua M.,Bisset, Kathryn A.,Leadbeater, Nicholas E.
supporting information, p. 4715 - 4719 (2018/07/06)
We present an alcohol oxidation strategy to access α-trifluoromethyl ketones (TFMKs) merging catalytic oxoammonium cation oxidation with visible-light photoredox catalysis. This work uses 4-acetamido-(2,2,6,6-tetramethyl-piperidin-1-yl)oxyl as an organic oxidant capable of generating TFMKs in good yields. The methodology serves as an improvement over previous reports of an analogous oxidation strategy requiring superstoichiometric quantities of oxidant. Both primary and secondary non-fluorinated alcohols can also be oxidised in good yields.
Development of (Trifluoromethyl)zinc Reagent as Trifluoromethyl Anion and Difluorocarbene Sources
Aikawa, Kohsuke,Toya, Wataru,Nakamura, Yuzo,Mikami, Koichi
supporting information, p. 4996 - 4999 (2015/11/03)
The trifluoromethylation of carbonyl compounds is accomplished by the stable (trifluoromethyl)zinc reagent generated and then isolated from CF3I and ZnEt2, which can be utilized as a trifluoromethyl anion source (CF3-). The reaction proceeds smoothly with diamine as a ligand and ammonium salt as an initiator, providing the corresponding trifluoromethylated alcohol products. Moreover, the (trifluoromethyl)zinc reagent can also be employed as a difluorocarbene source (:CF2) not only for gem-difluoroolefination of carbonyl compounds with phosphine but also for gem-difluorocyclization of alkenes or alkynes via the thermal decomposition, respectively.
Highly efficient synthesis of aryl and heteroaryl trifluoromethyl ketones via o-iodobenzoic acid (IBX)
Cheng, Huicheng,Pei, Yu,Leng, Faqiang,Li, Jingya,Liang, Apeng,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
, p. 4483 - 4486 (2013/07/26)
A two-step process for the synthesis of aryl and heteroaryl trifluoromethyl ketones from the corresponding aldehydes is described. Trifluoromethyl alcohols were prepared from aryl and heteroaryl aldehydes in excellent yields using catalytic amount of K2CO3. The trifluoromethyl alcohols were then oxidized conveniently and efficiently by o-iodoxybenzoic acid (IBX) under mild conditions to get the desired functionalized aryl and heteroaryl trifluoromethyl ketones.
Oxidation of α-trifluoromethyl alcohols using a recyclable oxoammonium salt
Kelly, Christopher B.,Mercadante, Michael A.,Hamlin, Trevor A.,Fletcher, Madison H.,Leadbeater, Nicholas E.
, p. 8131 - 8141 (2013/01/15)
A simple, mild method for the oxidation of α-trifluoromethyl alcohols to trifluoromethyl ketones (TFMKs) using the oxoammonium salt 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1) is described. Under basic conditions, oxidation proceeds rapidly and affords good to excellent yields of TFMKs, without concomitant formation of the hydrate. The byproduct of the oxidation, 4-acetylamino-2,2,6,6-tetramethyl-1- piperidinyloxy (1c), is easily recovered and can be conveniently reoxidized to regenerate the oxoammonium salt.
The reduction of aryl trifluoromethyl ketones by sodium borohydride. The hydride transfer process
Stewart, Ross,Teo, K. C.
, p. 2491 - 2496 (2007/10/02)
The rates of reduction of 17 aryl trifluoromethyl ketones by sodium borohydride in 2-propanol have been measured.The rho (ρ) value is 3.12, excluding the 4-amino and 4-dimethylamino groups, which both lower the rate to a greater extent than their ? values predict.The close correspondence between substituent effects for hydride addition in the methyl and trifluoromethyl series (excluding the amino groups) suggests that normal substituent effects are to be expected for oxidation processes involving hydride removal in trifluoromethyl compounds.The present results are consistent with the oxidation of aryl trifluoromethyl carbi ols by permanganate taking place by hydrogen atom abstraction.The effect of substituents on the rate of reduction of the trifluoromethyl ketones is almost identical to that on the equilibrium constant for formation of the ketone hydrates.The application of the reactivity-selectivity principle to the reduction reaction is also considered.Reduction of the 4-ethyl compound has ΔH = 2.7 kcal mol-1 and ΔS = -38 cal deg-1 mol-1.