86571-26-8Relevant articles and documents
Efficient Asymmetric Biomimetic Aldol Reaction of Glycinates and Trifluoromethyl Ketones by Carbonyl Catalysis
Cao, Jing,Cheng, Aolin,Liu, Tao,Song, Guanshui,Zhang, Kun,Zhang, Liangliang,Zhao, Baoguo,Zhao, Guoqing,Zhou, Qinghai
supporting information, p. 20166 - 20172 (2021/07/20)
The direct asymmetric aldol reaction of glycinates represents an intriguing and straightforward strategy to make biologically significant chiral β-hydroxy-α-amino-acid derivatives. But it is not easy to realize the transformation due to the disruption of the reactive NH2 group of glycinates. Inspired by the enzymatic aldol reaction of glycine, we successfully developed an asymmetric aldol reaction of glycinate 5 and trifluoromethyl ketones 4 with 0.1–0.0033 mol % of chiral N-methyl pyridoxal 7 a as the catalyst, producing chiral β-trifluoromethyl-β-hydroxy-α-amino-acid esters 6 in 55–82 % yields (for the syn-diastereomers) with up to >20:1 dr and 99 % ee under very mild conditions. The reaction proceeds via a catalytic cycle similar to the enzymatic aldol reaction of glycine. Pyridoxal catalyst 7 a activates both reactants at the same time and brings them together in a specific spatial orientation, accounting for the high efficiency as well as excellent diastereo- and enantioselectivities.
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.
Remote Regioselective Radical C-H Functionalization of Unactivated C-H Bonds in Amides: The Synthesis of gem-Difluoroalkenes
Hu, Qu-Ping,Cheng, Jing,Wang, Ying,Shi, Jie,Wang, Bi-Qin,Hu, Ping,Zhao, Ke-Qing,Pan, Fei
supporting information, p. 4457 - 4462 (2021/05/26)
The site-selective functionalization of unactivated aliphatic amines is an attractive and challenging synthetic approach. We herein report a general strategy for the remote site-selective functionalization of unactivated C(sp3)-H bonds in amides by photogenerated amidyl radicals to form gem-difluoroalkenes with trifluoromethyl-substituted alkenes. The site selectivity is controlled by a 1,5-hydrogen atom transfer (HAT) process of the amide. This photocatalyzed transformation shows both chemo- and site-selectivity, facilitating the formation of a secondary, tertiary, or quaternary carbon center.
Access to substituted trifluoromethyl ketones using the versatile synthetic intermediate (E)-1,1-dimethyl-2-(1,1,1-trifluoropropan-2-ylidene)hydrazine
Judd, Ted C.,Brown, Derek B.
supporting information, p. 4455 - 4458 (2017/10/30)
The N,N-dimethylhydrazone of 1,1,1-trifluoroacetone, (E)-1,1-dimethyl-2-(1,1,1-trifluoropropan-2-ylidene)hydrazine, has been shown to undergo a diverse set of reactions following deprotonation with n-butyl-lithium; including alkylation, addition to ketones and aldehydes, as well as palladium-catalyzed cross-couplings with aryl bromides. Mild hydrolysis of the N,N-dimethylhydrazone products from these transformations affords the corresponding trifluoromethyl ketones in good to excellent yields.
Synthesis of trifluoromethyl moieties by late-stage copper (I) mediated nucleophilic fluorination
Bermejo Góme, Antonio,González, Miguel A. Cortés,Lübcke, Marvin,Johansson, Magnus J.,Schou, Magnus,Szabó, Kálmán J.
, p. 51 - 57 (2017/01/12)
The nucleophilic fluorination of bromodifluoromethyl derivatives mediated by the complex (PPh3)3CuF is described. Under the reaction conditions, different trifluoroacetates, trifluoroketones, trifluoroarenes and trifluoroacetamides were obtained in good yields.
PERFLUORORALKYLATION OF CARBONYL COMPOUNDS
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Paragraph 0064; 0065, (2015/07/07)
The present invention provides a process for producing a compound comprising a perfluorinated alkyl group moiety from a carbonyl compound. Typically, the process includes contacting a carbonyl compound with a silane compound in the presence of a fluorohydrogenate ionic liquid under conditions sufficient to produce a compound comprising a perfluorinated alkyl group. The silane compound includes a perfluoroalkyl group.
Copper-Catalyzed Trifluoromethylation of Aliphatic N-Arylhydrazones: A Concise Synthetic Entry to 2-Trifluoromethylindoles from Simple Aldehydes
Prieto, Alexis,Landart, Mélissa,Baudoin, Olivier,Monteiro, Nuno,Bouyssi, Didier
, p. 2939 - 2943 (2015/09/28)
The copper-catalyzed C(sp2)-H trifluoromethylation of N,N-disubstituted hydrazones using the Togni reagent is demonstrated to proceed efficiently for aliphatic aldehyde-derived substrates. The success of the reactions relied on the choice of the N,N-diphenylamino group as the terminal hydrazone amino group where N,N-dialkylamino groups were preferred for (hetero)aromatic aldehyde-derived substrates. In addition, the trifluoromethylated N-arylhydrazones are shown to be ideal substrates for Fischer indole synthesis allowing a straightforward, three-step access to 2-trifluoromethylindole derivatives from simple aldehydes.
Stereoconvergent negishi arylations of racemic secondary alkyl electrophiles: Differentiating between a CF3 and an alkyl group
Liang, Yufan,Fu, Gregory C.
supporting information, p. 9523 - 9526 (2015/08/18)
In this report, we establish that a readily available nickel/bis(oxazoline) catalyst accomplishes a wide array of enantioconvergent cross-couplings of arylzinc reagents with CF3-substituted racemic secondary alkyl halides, a process that necessitates that the chiral catalyst be able to effectively distinguish between a CF3 and an alkyl group in order to provide good ee. We further demonstrate that this method can be applied without modification to the catalytic asymmetric synthesis of other families of fluorinated organic compounds.
Organocatalytic Aerobic Oxidation of α-Fluoroalkyl Alcohols to Fluoroalkyl Ketones at Room Temperature
Kadoh, Yoichi,Tashiro, Masayuki,Oisaki, Kounosuke,Kanai, Motomu
, p. 2193 - 2198 (2015/07/27)
The organocatalytic aerobic oxidation of electron-deficient α-fluoroalkyl alcohols at room temperature is described. The resulting fluoroalkyl ketones are versatile synthetic intermediates for a variety of fluorine-containing molecules. This otherwise difficult transformation has now been accomplished by the reaction of α-fluoroalkyl alcohols with N-oxyl radicals, catalytically generated from 9-azabicyclo[3.3.1]nonan-3-one N-oxyl/nitrogen oxide (keto-ABNO/NOx) and oxygen in acetic acid (AcOH), affording the corresponding fluoroalkyl ketones in high yield. This operationally simple reaction can be performed under mild conditions, and was applied to a wide range of alcohols (20 examples), thus demonstrating a high functional group tolerance. Moreover, a modified one-pot protocol based on this method was able to convert an aldehyde to a trifluoromethyl ketone on a gram scale.
Highly selective trifluoroacetic ester/ketone metathesis: An efficient approach to trifluoromethyl ketones and esters
Zhou, Yuhan,Yang, Dongmei,Luo, Gen,Zhao, Yilong,Luo, Yi,Xue, Na,Qu, Jingping
, p. 4668 - 4674 (2014/06/23)
A highly selective and atom efficient 'trifluoroacetic ester/ketone metathesis' has been sincerely witnessed. Enolizable alkyl (at least two non-hydrogen atoms) aryl ketones were found to react readily with ethyl trifluoroacetate under the promotion of NaH to afford trifluoroacetic ester/ketone exchange products, trifluoromethyl ketones (TFMKs), and aromatic acid esters, which were quite different from the general Claisen condensation products, 1,3-diketones. The outcome of the reaction between ketone and ethyl trifluoroacetate is strongly related to the structures of substrates, the steric congestion caused by alkyl group is in favor of the C-C bond cleavage. DFT investigation further disclosed that the metathesis reaction was a kinetically favored pathway. Using only a slight excess of cheap trifluoromethylation reagent, simple operation and mild conditions make it a practical method for preparation of TFMKs on large scale, as well as a new choice of converting aryl alkyl ketones to aromatic acid esters.
