82203-83-6Relevant articles and documents
Enantioselective Nickel-Catalyzed Alkyne-Azide Cycloaddition by Dynamic Kinetic Resolution
Liu, En-Chih,Topczewski, Joseph J.
supporting information, p. 5308 - 5313 (2021/05/04)
The triazole heterocycle has been widely adopted as an isostere for the amide bond. Many native amides are α-chiral, being derived from amino acids. This makes α-N-chiral triazoles attractive building blocks. This report describes the first enantioselective triazole synthesis that proceeds via nickel-catalyzed alkyne-azide cycloaddition (NiAAC). This dynamic kinetic resolution is enabled by a spontaneous [3,3]-sigmatropic rearrangement of the allylic azide. The 1,4,5-trisubstituted triazole products, derived from internal alkynes, are complementary to those commonly obtained by the related CuAAC reaction. Initial mechanistic experiments indicate that the NiAAC reaction proceeds through a monometallic Ni complex, which is distinct from the CuAAC manifold.
Regioselective Gold-Catalyzed Hydration of CF3- and SF5-alkynes
Cloutier, Mélissa,Roudias, Majdouline,Paquin, Jean-Fran?ois
, p. 3866 - 3870 (2019/05/24)
The regioselective gold-catalyzed hydration of CF3- and SF5-alkynes is described. The corresponding trifluoromethylated and pentasulfanylated ketones are obtained in up to 91% yield as single regioisomers showcasing the use of CF3 and SF5 as highly efficient directing groups in this reaction. Notably, this transformation represents the first use of CF3- and SF5-alkynes in gold catalysis.
Diverse copper(iii) trifluoromethyl complexes with mono-, bi- and tridentate ligands and their versatile reactivity
Zhang, Song-Lin,Xiao, Chang,Wan, Hai-Xing
supporting information, p. 4779 - 4784 (2018/04/11)
Cu(iii) trifluoromethyl complexes are proposed as essential intermediates for many copper-promoted trifluoromethylation reactions, but remain elusive and scarcely explored. We report herein the isolation and spectroscopic and X-ray crystallographic charac
Domino Hydroboration/Trifluoromethylation of Alkynes Using Fluoroform-Derived [CuCF3]
He, Lisi,Yang, Xinkan,Tsui, Gavin Chit
, p. 6192 - 6201 (2017/06/23)
A domino hydroboration/trifluoromethylation (formal hydrotrifluoromethylation) of alkynes using the fluoroform-derived [CuCF3] reagent is achieved. Synthetically useful (E)-alkenyl-CF3 building blocks and 1,1-bis(trifluoromethyl)-substituted alkenes can be prepared under ambient conditions in one pot/one step from alkynes. The ultimate source of CF3 is the inexpensive industrial waste fluoroform.
Dual-gold(I)-generated trifluoromethylation of terminal alkynes with Togni's reagent
Siah, Huey-San Melanie,Fiksdahl, Anne
, p. 24 - 33 (2017/03/10)
The interaction of a Au(I) catalyst (JohnPhosAu(I)-MeCN/SbF6) and the Togni's reagent 1, as a source of electrophilic trifluoromethyl group, has been studied in order to develop gold-catalysed alkyne trifluoromethylation reactions. Alkyne-CF3products were prepared in moderate yields (up to 46%) by electrophilic trifluoromethylation of terminal arylalkynes with Togni's reagent 1 in the presence of sub-stoichiometric amounts of gold catalyst (25%). The proposed addition-elimination reaction mechanism proceeds through a Au-Togni Reagent complex with a linear Togni Reagent-O-Au(I)-P-(phosphane) coordination mode (X-ray analysis). Alkyne deprotonation gives rapid formation of protonated Togni Reagent and a σ,π-acetylide dual-Au complex, confirmed by X-ray analysis. It was shown that the σ,π-dual-Au complex activates for trifluoromethylation, most likely by transfer of a [LAu]+fragment to the alkyne substrate. The resulting reactive π-Au+-alkyne intermediate probably undergoes O-/CF3-addition of Togni Reagent, and final elimination of Togni alcohol gives the alkyne-CF3product.
Syn-Fluoro- and -Oxy-trifluoromethylation of Arylacetylenes
Zhang, Song-Lin,Wan, Hai-Xing,Bie, Wen-Feng
, p. 6372 - 6375 (2017/12/08)
One-step concurrent fluoro-trifluoromethylation across the triple bond of arylacetylenes in a syn mode is enabled by the collaboration of (phen)CuIII(CF3)3 and CsF that produces chemo-, regio-, and stereoselectively (Z)-α-fluoro-β-CF3 styrenes. This method can be extended to achieve syn-oxy-trifluoromethylation and syn-aryl-trifluoromethylation of alkynes using phenoxides, alkoxides, or phenylboronic acid in place of CsF. It opens up new opportunities for preparing various functionalized trifluoromethylated Z-alkenes and demonstrates the potential of Cu(III)-CF3 complexes in organic synthesis.
Fluoroform-Derived CuCF3 for Trifluoromethylation of Terminal and TMS-Protected Alkynes
He, Lisi,Tsui, Gavin Chit
supporting information, p. 2800 - 2803 (2016/07/06)
An efficient trifluoromethylation reaction of alkynes using a fluoroform-derived CuCF3 reagent is described. The CF3 source is the inexpensive industrial waste fluoroform (CF3H). The air-stable CuCF3 reagent can be prepared in large quantities and is convenient to use. Synthetically useful trifluoromethylated alkynes containing a wide range of functional groups were successfully synthesized under mild conditions. Both terminal and TMS-protected alkynes gave the products in one step. The beneficial effect of a diamine ligand tetramethylethylenediamine (TMEDA) with the fluoroform-derived CuCF3 reagent was also demonstrated.
Cu-promoted oxidative trifluoromethylation of terminal alkynes with difluoromethylene phosphobetaine
Deng, Xiaoyun,Lin, Jinhong,Zheng, Jian,Xiao, Jichang
, p. 689 - 693 (2014/10/15)
Difluoromethylene phosphobetaine (Ph3P+CF 2CO2-, PDFA), a known difluorocarbene reagent, was found to be able to efficiently trifluoromethylate terminal alkynes in the presence of Cu(I) and potassium fluoride. The transformation proceeded smoothly to afford the corresponding trifluoromethylated acetylenes in moderate yields. A difluorocarbene precursor, difluoromethylene phosphobetaine (Ph 3P+CF2CO2-, PDFA) was found to be able to act as a trifluoromethylating reagent in the presence of fluoride. The oxidative trifluoromethylation of terminal alkynes with PDFA promoted by Cu(I) occurred smoothly to give the corresponding trifluoromethylated acetylenes in moderate yields. Copyright
Practical methods for the synthesis of trifluoromethylated alkynes: Oxidative trifluoromethylation of copper acetylides and alkynes
Tresse, Cedric,Guissart, Celine,Schweizer, Stephane,Bouhoute, Yassine,Chany, Anne-Caroline,Goddard, Mary-Lorene,Blanchard, Nicolas,Evano, Gwilherm
supporting information, p. 2051 - 2060 (2014/07/07)
Two practical and complementary methods are reported for the synthesis of trifluoromethylated alkynes. The first one, a mix-and-stir process, is based on the oxidative trifluoromethylation of readily available and bench-stable copper acetylides while the second one, which displays a broad substrate scope and has several advantages over existing procedures, is based on the oxidative copper-catalyzed direct trifluoromethylation of terminal alkynes. Both reactions provide user-friendly processes for the synthesis of trifluoromethylated acetylenes which can be easily obtained from readily available starting materials.
Copper-mediated trifluoromethylation of potassium alkynyltrifluoroborates with Langlois' reagent Dedicated to Professor Pierre Vogel on the occasion of his 70th birthday
Dubbaka, Srinivas Reddy,Nizalapur, Shashidhar,Atthunuri, Azmi Reddy,Salla, Manohar,Mathew, Thresen
, p. 2118 - 2121 (2014/03/21)
Synthesis of trifluoromethylated acetylenes by copper-mediated trifluoromethylation of potassium alkynyltrifluoroborates with CF3 radicals generated from NaSO2CF3 and tert-butyl hydroperoxide (TBHP) is communicated. The trifluoromethylated acetylenes were obtained in good to moderate yields. The presented method tolerates a wide range of aromatic, heteroaromatic, and aliphatic potassium alkynyltrifluoroborates.
