Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

• Mio Matsumura,
• Kaho Tsukada,
• Kiwa Sugimoto,
• Yuki Murata and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

• –Prakash reagent (TMSCF3) in the presence of Cs2CO3 as base in MeCN at 0 °C gave product 7 with a trifluoromethyl group. Stefani et al. reported the 1,3-dipolar azide–alkyne cycloaddition (AAC) of organotellanyl alkynes with organic azides in the presence of a copper reagent to form 5-organotellanyl-1,2,3

• phenyllithium in THF at −78 °C led to a nucleophilic substitution reaction with the elimination of the ethynyl group to form the desired phenylimidazopyridinyl selenide 6a in 49% yield. In the reaction with n-butyllithium, alkyl derivative 6b was isolated in the same way. The reaction of 4aa with the Ruppert

Synthesis of trifluoromethyl ketones by nucleophilic trifluoromethylation of esters under a fluoroform/KHMDS/triglyme system

• Yamato Fujihira,
• Yumeng Liang,
• Makoto Ono,
• Kazuki Hirano,
• Takumi Kagawa and
• Norio Shibata

Beilstein J. Org. Chem. 2021, 17, 431–438, doi:10.3762/bjoc.17.39

• TFMK moiety is a proven effective metal chelator in various enzyme inhibitors (Figure 1b) [58][59][60][61][62][63][64][65]. Several useful methods exist for preparing trifluoromethyl ketones [66][67], such as the direct trifluoromethylation of esters by the Ruppert–Prakash reagent (Me3SiCF3) [68][69

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• , preparation, and ease of storage. The generation of difluorocarbene from trimethyl(trifluoromethyl)silane: One more modified method, which also increases the rate of the reaction, is the generation of difluorocarbene from TMSCF3 (31), which is also known as the Ruppert–Prakash reagent [39]. The advantages of

Regioselective cobalt(II)-catalyzed [2 + 3] cycloaddition reaction of fluoroalkylated alkynes with 2-formylphenylboronic acids: easy access to 2-fluoroalkylated indenols

• Tatsuya Kumon,
• Miroku Shimada,
• Jianyan Wu,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 2193–2200, doi:10.3762/bjoc.16.184

• reaction of the CF3-containing phthalide B prepared from the 1,2-diester A with the Ruppert–Prakash reagent (TMSCF3) in the presence of a catalytic amount of CsF (Scheme 1a). According to this paper, phthalide B reacted smoothly with phenylthiomethyllithium to give the corresponding CF3-containing indanone

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

• Vyacheslav I. Supranovich,
• Vitalij V. Levin and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

• been extensively investigated over the last decade [8][9][10][11][12][13]. Recently, (bromodifluoromethyl)trimethylsilane (1) which can be readily obtained from the Ruppert–Prakash reagent [14][15], has been introduced as a reagent for the synthesis of various difluorinated compounds [16][17][18]. This

Copper-based fluorinated reagents for the synthesis of CF₂R-containing molecules (R ≠ F)

• Louise Ruyet and
• Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

• after reduction of the Ruppert–Prakash reagent with sodium borohydride [39]. The key of success was the use of bulky IPr and SIPr ligands to stabilize the organometallic species. Indeed, in the case of IPr as a ligand, the complex was stable in solution at room temperature for at least 24 hours. The

• synthetic route to the generation of the PhenCuCF2CF3 reagent [78]. Indeed, they demonstrated that the Ruppert–Prakash reagent was a suitable source for the generation of tetrafluoroethylene in the presence of a catalytic amount of NaI. Then, the cupration of the tetrafluoroethylene led to the formation of

Copper-promoted/copper-catalyzed trifluoromethylselenolation reactions

• Clément Ghiazza and
• Anis Tlili

Beilstein J. Org. Chem. 2020, 16, 305–316, doi:10.3762/bjoc.16.30

• 2003. Therein, the association of the Ruppert–Prakash reagent with ammonium fluoride in the presence of a slight excess of Se allowed the facile synthesis of Me4NSeCF3 (Scheme 9) [26]. Today, Me4NSeCF3 is routinely used by several research groups. In the past five years, this stable and easy-to-handle

• tandem formation of C–Se and Se–fluoroalkyl bonds have emerged in the last five years. In 2014, Hor and Weng reported the trifluoromethylselenolation of (hetero)aryl iodides and alkyl bromides with the Ruppert–Prakash reagent, TMSCF3, elemental selenium, potassium fluoride, and silver carbonate under

• trifluoromethylation in a one-pot procedure with the Ruppert–Prakash reagent (Scheme 15, conditions III) [41]. The corresponding trifluoromethylselenylated (hetero)aryl products were obtained in moderate to good yields using both electron-deficient and -rich starting materials, respectively. Interestingly, the authors

6’-Fluoro[4.3.0]bicyclo nucleic acid: synthesis, biophysical properties and molecular dynamics simulations

• Sibylle Frei,
• Andrei Istrate and
• Christian J. Leumann

Beilstein J. Org. Chem. 2018, 14, 3088–3097, doi:10.3762/bjoc.14.288

• improving the already existing protocol [50]. The sugars 2α/β were then individually treated with the Ruppert–Prakash reagent (TMSCF3) as difluorocarbene precursor and sodium iodide as initiator [52], furnishing the exo-tricyclic sugars 3α/β as major isomers. The closer evaluation of this reaction revealed

Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides

• Masanori Inaba,
• Tatsuya Sakai,
• Shun Shinada,
• Tsuyuka Sugiishi,
• Yuta Nishina,
• Norio Shibata and
• Hideki Amii

Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12

• -cyanobenzaldehyde (2) and subsequent intramolecular cyclization. Results and Discussion The reaction procedure is very simple. A mixture of 2-cyanobenzaldehyde (2), CF3–SiMe3 (so-called Ruppert–Prakash reagent) [20][21], and a catalytic amount of KF in anhydrous DMF was stirred at room temperature for 1 h. After

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• explored the trifluoromethylation of primary and secondary alkylboronic acids with the Ruppert–Prakash reagent (TMSCF3) (Scheme 17) [32]. These alkylboronic acids were prepared from the corresponding alkyl halides or tosylates by using their previously developed Cu-catalyzed borylation method [33]. Both

• tetrahydroisoquinoline derivatives using DDQ and Ruppert–Prakash reagent (Scheme 31). A variety of amines proceeded smoothly to give the corresponding products in 15–90% yields under mild conditions. Based on previous literature, the author proposed a possible mechanism in Scheme 31. Firstly, oxidation of N-substituted

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• popular nucleophilic trifluoromethylating reagent is certainly the trifluoromethyltrimethylsilane, CF3SiMe3, known as the Ruppert–Prakash reagent discovered in 1984 by Ruppert and applied for trifluoromethylation in 1989 by Prakash and Olah. More recently, renewed investigation on the use of fluoroform

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• . and Buchwald et al. used the Ruppert–Prakash reagent (CF3–SiMe3) directly as a CF3− source [46][47]. From CF3–SiMe3, Hartwig et al. developed a new combination of Ir-catalyzed C–H borylation and oxidative cross-coupling using [(phen)CF3Cu] [48]. Grushin et al. utilized fluoroform for the preparation

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• , and thus a more dramatic change to the surface properties. Experimental Bromoform (CHBr3), chloroform (CHCl3) and the Ruppert–Prakash reagent (CF3Si(CH3)2) [33][34] were used as the carbene precursors for surface modification, with the resultant carbenes generated in solution. For dibromo- and

• time required to be optimised. The reaction temperature was kept at 25 °C and the phase-transfer catalyst, benzyltriethylammonium chloride (BTEAC) was chosen to generate the :CX2 carbenes, and minimise exposure of the wafers to the base. The Ruppert–Prakash reagent (TMSCF3) was used to prepare the gem

Deoxygenative gem-difluoroolefination of carbonyl compounds with (chlorodifluoromethyl)trimethylsilane and triphenylphosphine

• Fei Wang,
• Lingchun Li,
• Chuanfa Ni and
• Jinbo Hu

Beilstein J. Org. Chem. 2014, 10, 344–351, doi:10.3762/bjoc.10.32

• and the application of the former in deoxygenative gem-difluoroolefination of carbonyl compounds via Wittig-type reaction are reported. Results and Discussion (Halodifluoromethyl)trimethylsilanes including TMSCF3 (Ruppert–Prakash reagent), TMSCF2Cl, and TMSCF2Br are initially prepared by reductive

Synthesis, characterization and initial evaluation of 5-nitro-1-(trifluoromethyl)-3H-1λ³,2-benziodaoxol-3-one

• Nico Santschi,
• Roman C. Sarott,
• Elisabeth Otth,
• Reinhard Kissner and
• Antonio Togni

Beilstein J. Org. Chem. 2014, 10, 1–6, doi:10.3762/bjoc.10.1

• % average yield of five experiments). This step was routinely carried out on a 3 gram scale in less than 5 minutes. Finally, introduction of the trifluoromethyl group was achieved by stirring 6 and anhydrous KF in hot MeCN, followed by treatment with Ruppert–Prakash reagent (TMSCF3) at 0 °C yielding 10–35

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• CF3-source. A single study on palladium-catalyzed trifluoromethylation of sp2-C–H bonds was reported by G. Liu and coworkers [72]. It described the introduction of a CF3 group at the 2-position of indoles using palladium acetate as a catalyst and the Ruppert–Prakash reagent TMSCF3. A screening of

• and F.-L. Qing, where catalytic copper was used in the trifluoromethylation of sp2-C–H bonds by a nucleophilic CF3-releasing reagent [91]. In this paper, heteroarenes or arenes bearing acidic sp2-C–H bonds were trifluoromethylated by the Ruppert–Prakash reagent in presence of catalytic copper(II), a

• required such as Ruppert–Prakash reagent (TMSCF3) or TESCF3 to generate a CF3-nucleophile, and S-(trifluoromethyl)thiophenium salts or Togni’s reagent to generate a CF3+-electrophile, an alternative approach has recently been reported, by different groups, where highly reactive CF3 radicals are generated

Cu-catalyzed trifluoromethylation of aryl iodides with trifluoromethylzinc reagent prepared in situ from trifluoromethyl iodide

• Yuzo Nakamura,
• Motohiro Fujiu,
• Tatsuya Murase,
• Yoshimitsu Itoh,
• Hiroki Serizawa,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2013, 9, 2404–2409, doi:10.3762/bjoc.9.277

• . Keywords: organo-fluorine; Ruppert–Prakash reagent; trifluoromethyl; trifluoromethylation; trifluoromethyl zinc; Introduction Organo-fluorine compounds have received considerable attention in the fields of biomedical chemistry, agrochemistry, and organic material science due to their unique chemical

Regioselective 1,4-trifluoromethylation of α,β-unsaturated ketones via a S-(trifluoromethyl)diphenylsulfonium salts/copper system

• Satoshi Okusu,
• Yutaka Sugita,
• Etsuko Tokunaga and
• Norio Shibata

Beilstein J. Org. Chem. 2013, 9, 2189–2193, doi:10.3762/bjoc.9.257

• of 1,4-additive trifluoromethylation of (trifluoromethyl)trimethylsilane (Me3SiCF3, Ruppert–Prakash reagent) to very specific substrates such as trans-1-benzoyl-2-(dimethylamino)ethylene [12], 2-polyfluoroalkylchromones [13][14], isoxazoles with a nitro group at the 4-position [15], and Morita–Baylis

• –Hillman adducts (via SN2’ [16] or successive SN2’/SN2’ mode [17]). Sevenard and co-workers reported the nucleophilic 1,4-trifluoromethylation to chromones, coumarins and cyclohex-2-enone using the Ruppert–Prakash reagent, which was achieved by blocking the carbonyl moiety of the substrates with a bulky

• only a trace amount of the desired product 2a under the same reaction conditions (Table 1, entries 13–15). No reaction was observed using Ruppert–Prakash reagent in the presence of Cu under the same conditions (Table 1, entry 16). In all the cases, the reaction was regioselective and a trace amount of

Enantioselective nucleophilic difluoromethylation of aromatic aldehydes with Me₃SiCF₂SO₂Ph and PhSO₂CF₂H reagents catalyzed by chiral quaternary ammonium salts

• Chuanfa Ni,
• Fang Wang and
• Jinbo Hu

Beilstein J. Org. Chem. 2008, 4, No. 21, doi:10.3762/bjoc.4.21

• introduction of a trifluoromethyl group into aldehydes and ketones with Ruppert-Prakash reagent, (trifluoromethyl)trimethylsilane, Me3SiCF3 and other reagents [19][20][21][22][23][24][25][26][27][28][29]. Although one-step nucleophilic difluoromethylation with R3SiCF2H is challenging regarding generality and

Efficient 1,4-addition of α-substituted fluoro(phenylsulfonyl)methane derivatives to α,β-unsaturated compounds

• G. K. Surya Prakash,
• Xiaoming Zhao,
• Sujith Chacko,
• Fang Wang,
• Habiba Vaghoo and
• George A. Olah

Beilstein J. Org. Chem. 2008, 4, No. 17, doi:10.3762/bjoc.4.17

• Lewis acids to protect the carbonyl of Michael acceptors and thus sucessfully transferred the trifluoromethyl anion generated from the "Ruppert-Prakash reagent" (TMS-CF3) in a 1,4-manner rather than the favored 1,2-addition. Portella et al. [20] have shown that 1,4-addition of difluoroenoxysilanes to