Synthesis of O⁶-alkylated preQ₁ derivatives

• Laurin Flemmich,
• Sarah Moreno and
• Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

• & 112.6 (C(arom, DMTr)), 74.5 (CAr3(DMTr)), 70.3 (CAr3(DMTr)), 55.3 (H3CO(DMTr)), 53.4 (H3CO(6)), 38.9 (H2CC(7)) ppm; ESIMS (m/z): [M + H]+ calcd, 798.3650; found, 798.3629. O6-Methyl preQ1 (trifluoroacetate salt) (2). Compound 6 (120 mg, 150 µmol) was dissolved in 500 µL dichloromethane. Trifluoroacetic

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• called polyazulene (Scheme 2). The elemental analysis of this polymer revealed that it existed as a 71:29 mixture of polymer 3 or 3’ bearing a heptafulvene structure (true polyazulene) and cycloheptatrienyl trifluoroacetate 2. The temperature and reaction time determined the overall yield and the Mn of

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

• Zsanett Benke,
• Attila M. Remete and
• Loránd Kiss

Beilstein J. Org. Chem. 2021, 17, 2051–2066, doi:10.3762/bjoc.17.132

• used in our CM steps. CM reactions of compound (±)-4 were investigated first. With 4-bromo-3,3,4,4-tetrafluorobut-1-ene and allyl 2,2,2-trifluoroacetate, no CM product was observed. However, CM reactions with 1,1,1,3,3,3-hexafluoropropan-2-yl acrylate (7c) were successful (Scheme 1 and Table 1). When

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• % from benzyl alcohol (16), alongside 50% of the trifluoroacetate 18. Carrying out the same process via a flow-based protocol allowed for the formation of benzaldehyde (17) in 91% yield with only 8% of the accompanying side product 18 [88]. Similarly, a stereoselective alkylation of an Evans’ type

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• with Selectfluor® [153]. The authors justified the use of protecting groups due to their extensive use in peptide synthesis. Of all the PGs tested, phthalimide (Phth)- and trifluoroacetate (TFA)-protected substrates underwent photosensitized C–H fluorination to give the highest yield of 80% and 71% of

The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization

• Sharna-kay Daley and
• Nadale Downer-Riley

Beilstein J. Org. Chem. 2020, 16, 2026–2031, doi:10.3762/bjoc.16.169

• phenyliodine diacetate (PIDA) and phenyliodine bis(trifluoroacetate) (PIFA), have been utilized for oxidative dimerization reactions [14][15]. The use of these one-electron oxidants, as well as non-metallic reagents, plays an important role in accessing symmetrical and asymmetrical biaryls and polyaryls [1

Fluorohydration of alkynes via I(I)/I(III) catalysis

• Jessica Neufeld,
• Constantin G. Daniliuc and
• Ryan Gilmour

Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135

• (64% and 56% yield, respectively, Table 1, entries 2 and 4). Fluorinated solvents such as hexafluoroisopropanol (HFIP) or ethyl trifluoroacetate (ETFA) led to similar results (52% and 50% yield, respectively, Table 1, entries 5 and 6). Switching to non-halogenated solvents such as acetonitrile or

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• stereoisomer, despite the presence of two isomers in the starting materials 3. The 1H NMR and 13C NMR spectra clearly showed the chemical equivalence of the two ortho-palladated fragments, while 19F NMR spectra showed the equivalence of the bridging trifluoroacetate ligands. This means that only the transoid

• Figure 5, provides additional information. Complex 4a has a dinuclear structure in which each Pd atom is surrounded by one C,N-ortho-metallated oxazolone and two oxygen atoms of the trifluoroacetate ligands, which act as bridging ligands between the two Pd(C^N) fragments. In turn, the two Pd(C^N

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

• Zeguo Fang,
• Nawaf Al-Maharik,
• Peer Kirsch,
• Matthias Bremer,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

• developed by Bosch [16]. Accordingly, treatment of 16a with butyl vinyl ether, bathophenanthroline (BPhen) and Et3N, using palladium(II) trifluoroacetate as a catalyst, gave vinyl ether 17 in 62% yield in a single step. Finally, difluorocarbene-mediated difluorocyclopropanation generated 10 in 50% yield

Synthesis and circularly polarized luminescence properties of BINOL-derived bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys)

• Ryo Takishima,
• Yuji Nishii,
• Tomoaki Hinoue,
• Yoshitane Imai and
• Masahiro Miura

Beilstein J. Org. Chem. 2020, 16, 325–336, doi:10.3762/bjoc.16.32

• unsymmetrically substituted pyridines 3a–c in high yields. We then examined the oxidative cyclization of these compounds under the standard conditions adopting Pd(TFA)2 (30 mol %, TFA = trifluoroacetate) and AgOAc (3.0 equiv) as catalyst and oxidant, respectively, in pivalic acid as solvent (Scheme 3). Since the

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• purification [17][18]. As an example for the second category, Jiao and co-workers developed an organocatalytic C3–H alkenylation of indoles by the reaction of indoles with α,β-unsaturated aldehydes in presence of morpholin-4-ium trifluoroacetate as a catalyst and a stoichiometric amount of DDQ to achieve

Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• triazolium salts show diverse aggregation via halogen bonding between C–I bonds and anions. Triazolium with halide anions exists as a tetramer with saddle conformation. Triazolium tetrafluoroborate exists as a trimer with Chinese lantern shape conformation. Triazolium trifluoroacetate and acetate exist as

• compounds show XB interactions between the triazolium moiety and anions, and different aggregations are formed. Triazolium with halide anions exists as tetramers with saddle conformation. Triazolium tetrafluoroborate exists as trimer with Chinese lantern shape conformation. Triazolium trifluoroacetate and

• -triazolium salts with different anions. When the anion is chloride, bromide or iodide, the crystal is a tetramer. Strong XB was observed in these forms. When the anion is changed to tetrafluoroborate, it takes Chinese lantern shape as a trimer. Triazolium trifluoroacetate and acetate exist as a dimer, while

Construction of trisubstituted chromone skeletons carrying electron-withdrawing groups via PhIO-mediated dehydrogenation and its application to the synthesis of frutinone A

• Qiao Li,
• Chen Zhuang,
• Donghua Wang,
• Wei Zhang,
• Rongxuan Jia,
• Fengxia Sun,
• Yilin Zhang and
• Yunfei Du

Beilstein J. Org. Chem. 2019, 15, 2958–2965, doi:10.3762/bjoc.15.291

• generation of some unidentified byproducts. A solvent screening identified DMF to be the most appropriate solvent for this transformation (Table 1, entries 1–9). Other commonly employed oxidants, including phenyliodine(III) diacetate (PIDA), phenyliodine(III) bis(trifluoroacetate) (PIFA), and iodylbenzene

AgNTf₂-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives

• Ziping Cao,
• Jiekun Zhu,
• Li Liu,
• Yuanling Pang,
• Laijin Tian,
• Xuejun Sun and
• Xin Meng

Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255

• AgOTF (silver trifluoroacetate) salts can catalyze the proceeding of the reaction at 80 °C, affording the desired pyrrole 10aa in 42% and 28% yields (Table 1, entries 2 and 3), respectively. The hydrolytic product 11 was also obtained in 55% yield when AgOTF was used as the catalyst. Other silver

A review of the total syntheses of triptolide

• Xiang Zhang,
• Zaozao Xiao and
• Hongtao Xu

Beilstein J. Org. Chem. 2019, 15, 1984–1995, doi:10.3762/bjoc.15.194

• trifluoroacetate 60 by a known electrophilic substitution procedure that was developed by Tahara and co-workers [64]. Curtius rearrangement of 60 gave an isocyanate intermediate, which was reduced with LiAlH4 followed by reductive amination affording tertiary amine intermediate 61. Oxidation of 61 to its

The cyclopropylcarbinyl route to γ-silyl carbocations

• Xavier Creary

Beilstein J. Org. Chem. 2019, 15, 1769–1780, doi:10.3762/bjoc.15.170

• cyclopropylcarbinyl alcohol, which was available from methyl 2-diazopropanoate by a process completely analogous to the synthesis of the phenyl analog 17. The mesylate derivative was too reactive for rates to be measured and hence the trifluoroacetate derivative 48 was studied. Acetolysis gave the acetate 50 along

• with a smaller amount of methylcyclobutene (51, Scheme 10). This reactivity is completely analogous to that seen in the phenyl and hydrogen analogs 19 and 31, i.e., a mechanistic scheme involving the γ-trimethylsilyl-stabilized cation 52 is likely. The isomeric trifluoroacetate 49 (shown in Table 1

• ) gives methylcyclobutene (51) (68%) as the major acetolysis product, along with minor products that are identical to those previously reported [52] in solvolysis of the trifluoroacetate derivative of (1r,3r)-1-methyl-3-(trimethylsilyl)cyclobutanol. As in the case of mesylate 32, the γ-trimethylsilyl

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

• Victoria V. Lipson,
• Tetiana L. Pavlovska,
• Nataliya V. Svetlichnaya,
• Anna A. Poryvai,
• Nikolay Yu. Gorobets,
• Erik V. Van der Eycken,
• Irina S. Konovalova,
• Svetlana V. Shiskina,
• Alexander V. Borisov,
• Vladimir I. Musatov and
• Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

• structure of 1-([1,1'-biphenyl]-4-yl)-5-oxo-7-phenyl-6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-3-aminium 2,2,2-trifluoroacetate 9i according to X-ray diffraction data. Thermal ellipsoids of atoms are shown at 50% probability level. Molecular structure of 3-(2-amino-4-phenyl-1H-imidazol-5-yl)-3-(p-tolyl

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• trifluoroacetate (Scheme 7). Unexpectedly, this test experiment, performed with 7a at room temperature, led after 24 h not to the expected, symmetric 1,3-di(adamantyloxy)imidazolium salt 13h but to the trifluoroacetate of the starting material, i.e., compound 14, formed side by side with adamantan-1-ol. Apparently

• obtained in high yields. Attempted adamantylation of a 1-(adamantyloxy)imidazole 3-oxide with 1-bromoadamantane or adamantan-1-yl trifluoroacetate was unsuccessful. Nevertheless, the corresponding symmetric 1,3-di(adamantyloxy)imidazolium bromide was obtained in the reaction of adamantyloxyamine with

• trifluoroacetate (CF3CO2Ad) was prepared following a known protocol [38]. 1-Bromoadamantane, 1-bromopentane (12a) and 1-bromododecane (12b) were commercial reagents used in the studied reactions with no additional purification. General procedure for the preparation of imidazole 3-oxides 7 (procedure A): A solution

A convenient and practical synthesis of β-diketones bearing linear perfluorinated alkyl groups and a 2-thienyl moiety

• Ilya V. Taydakov,
• Yuliya M. Kreshchenova and
• Ekaterina P. Dolotova

Beilstein J. Org. Chem. 2018, 14, 3106–3111, doi:10.3762/bjoc.14.290

• ]. This compound was first obtained by Reid and Calvin in 1950 [15] by Claisen condensation of 2-acetylthiophene and ethyl trifluoroacetate in the presence of NaOEt in Et2O (Scheme 1). The purification procedure was laborious and included copper chelate precipitation and its subsequent acid decomposition

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• trichloroacetate and trifluoroacetate anions 47b,c. Following this method, various aromatic aldehydes bearing electron-withdrawing or donating groups (-NO2, -Cl, -OMe, -Me) 7 have been used to prepare the desired products in 85–95% yields. Aliphatic aldehydes produced complex mixtures of products using these

Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles

• Takashi Go,
• Akane Morimatsu,
• Hiroaki Wasada,
• Genzoh Tanabe,
• Osamu Muraoka,
• Yoshiharu Sawada and
• Mitsuhiro Yoshimatsu

Beilstein J. Org. Chem. 2018, 14, 2722–2729, doi:10.3762/bjoc.14.250

• TFAA to form sulfonium salt 14, which is characterised by an intramolecular double bond [34][35]. A less substituted double bond easily approaches the sulfonium ion and undergoes an addition reaction to produce intermediate 15. The trifluoroacetate anion attacks the posterior side of the α-carbon of

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• -triazolodiazepinium salts 10, the anion AlCl3(OAc)− in the initially formed products was replaced with a suitable counter ion such as chloride, trifluoroacetate and picrate, which proved to be a useful way to facilitate the isolation of the target salts 10. In order to further explore the scope and generality in view

Synthesis of trifluoromethylated 2H-azirines through Togni reagent-mediated trifluoromethylation followed by PhIO-mediated azirination

• Jiyun Sun,
• Xiaohua Zhen,
• Huaibin Ge,
• Guangtao Zhang,
• Xuechan An and
• Yunfei Du

Beilstein J. Org. Chem. 2018, 14, 1452–1458, doi:10.3762/bjoc.14.123

• and phenyliodine bis(trifluoroacetate) (PIFA) were tested, but the results indicated that they were ineffective to further improve the yields (Table 1, entries 11 and 12). With the optimized conditions in hand, we next explored the substrate scope for this newly established one-pot oxidative

Rapid transformation of sulfinate salts into sulfonates promoted by a hypervalent iodine(III) reagent

• Elsa Deruer,
• Vincent Hamel,
• Samuel Blais and
• Sylvain Canesi

Beilstein J. Org. Chem. 2018, 14, 1203–1207, doi:10.3762/bjoc.14.101

• ). To verify our hypothesis tosyl-sulfinate 1 was treated with iodanes such as sodium periodate (NaIO4), Dess-Martin periodinane (DMP) [33], 2-iodoxybenzoic acid (IBX) [34], (diacetoxyiodo)benzene (DIB), phenyliodine(III) bis(trifluoroacetate) (PIFA) in the presence of methanol. (III)-Iodanes and (V

Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system

• Toshifumi Dohi,
• Shohei Ueda,
• Kosuke Iwasaki,
• Yusuke Tsunoda,
• Koji Morimoto and
• Yasuyuki Kita

Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94

• ), phenyliodine(III) bis(trifluoroacetate) (PIFA), and iodosobenzene, has since become a popular choice for benzylic oxidations, which further expanded the scope and availability of methods for direct C–H functionalization and several coupling reactions [42][43][44][45][46][47][48][49][50]. As such, we reported