Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

• Marcin Kaźmierczak and
• Henryk Koroniak

Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69

• with potential biological activity. Experimental General methods 1H NMR, 13C NMR, 19F NMR and 31P NMR spectra were obtained on a Bruker ASCEND 400 (400 MHz) and a Bruker ASCEND 600 (600 MHz) spectrometer. All 2D spectra were recorded on a Bruker ASCEND 600 (600 MHz) spectrometer. 1H NMR chemical shifts

• were expressed in parts per million downfield from tetramethylsilane (TMS) as an internal standard (δ = 0) in CDCl3 or CD3CN. 13C NMR chemical shifts were expressed in parts per million downfield from CDCl3 (δ = 77.0) or CD3CN (δ = 1.39) as internal standards. 19F NMR chemical shifts were expressed in

• equiv) and DIPEA (2 equiv) in DMF under an argon atmosphere. The reaction mixture was activated for 5 min, followed by the addition of amine 13 (1 equiv) in DMF. Stirring was continued at this temperature for 30 min and then the solution was stirred for 2–3 h at room temperature (monitored by 31P or 19F

Cascade trifluoromethylthiolation and cyclization of N-[(3-aryl)propioloyl]indoles

• Ming-Xi Bi,
• Shuai Liu,
• Yangen Huang,
• Xiu-Hua Xu and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2020, 16, 657–662, doi:10.3762/bjoc.16.62

• ), which suggested that the radical process was probably involved in these transformations. Notably, no TEMPO-trapped product was detected by 19F NMR spectra of the crude reaction mixtures. On the basis of these results and literature studies [21][23][42][43][44][45][46][47], a plausible reaction mechanism

Asymmetric synthesis of CF₂-functionalized aziridines by combined strong Brønsted acid catalysis

• Xing-Fa Tan,
• Fa-Guang Zhang and
• Jun-An Ma

Beilstein J. Org. Chem. 2020, 16, 638–644, doi:10.3762/bjoc.16.60

• ) were added and the mixture was reacted at rt for 24 hours unless otherwise annotated. The yields are those of isolated products, and the dr was determined by 19F NMR analysis of the crude mixture. The results in parentheses are those of isolated products after the dissolution–filtration process: The

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• of TIPS-ethynyl-substituted BODIPY derivatives 3–6 were characterized by 1H and 19F NMR spectroscopy, high-resolution mass spectrometry, and X-ray crystallographic analysis. The solid-state structures of the diethynyl-substituted BODIPYs were unambiguously elucidated by X-ray diffraction analysis (3a

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

• ), 19F NMR (376 MHz, CDCl3) δ 69.06; HRMS–APCI (m/z): [M + H]+ calcd for C38H35F2N2O2, 589.2644; found, 589.2661. The enantiomeric purity was confirmed by HPLC analysis: CHIRAL ART Cellulose-SB column, n-hexane/chloroform 95:5, 1.0 mL/min, 40 °C; (S)-2: tR = 9.86 min, (R)-2: tR = 21.29 min, UV detection

Formal preparation of regioregular and alternating thiophene–thiophene copolymers bearing different substituents

• Atsunori Mori,
• Keisuke Fujita,
• Chihiro Kubota,
• Toyoko Suzuki,
• Kentaro Okano,
• Takuya Matsumoto,
• Takashi Nishino and
• Masaki Horie

Beilstein J. Org. Chem. 2020, 16, 317–324, doi:10.3762/bjoc.16.31

• MHz), 19F NMR (376 MHz), and 13C{1H} NMR (100 MHz) spectra were measured on a JEOL ECZ400 spectrometer as a CDCl3 solution, unless otherwise noted. The chemical shifts were expressed in ppm with CHCl3 (7.26 ppm for 1H), C6F6 (−164.9 ppm for 19F), or CDCl3 (77.16 ppm for 13C) as internal standards. IR

• Hz, 2H), 6.79 (s, 1H), 6.91 (d, J = 5.0 Hz, 1H), 7.17 (d, J = 5.0 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 0.4, 2.1, 18.3, 20.5 (br), 23.4, 27.4, 29.0, 30.4 (t, J = 22 Hz), 34.5, 124.3, 125.1, 126.0, 129.7, 130.2, 133.6, 137.6, 140.3; 19F NMR (376 MHz, C6F6) δ −129.2, −127.6, −117.6, −84.2; IR (ATR

• , 1H); 13C{1H} NMR (100 MHz, CDCl3) δ −0.2, 2.0, 17.6, 20.5 (br), 23.1, 27.4, 29.0, 30.4 (t, J = 22 Hz), 34.3, 124.3, 125.1, 126.0, 129.7, 130.2, 133.6, 137.6, 140.2; 19F NMR (376 MHz, C6F6) δ −129.2, −127.6, −117.6, −84.2; IR (ATR): 2958, 1252, 1233, 1167, 1134, 1046, 870, 841, 800, 783, 754, 719, 689

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• solvents.a Supporting Information Supporting Information File 252: Experimental procedures and 1H, 13C, 11B and 19F NMR spectra for all synthesized compounds. Funding This work was jointly supported by grants from CNPq and FACEPE.

• propargylating agent in a very regioselective way [36][37]. Thus, allenylboronic acid pinacol ester (1) was converted into the corresponding trifluoroborate using the procedure described by Lloyd-Jones and co-worker [38]. The desired product 4 was obtained in good yield and characterized by 1H, 13C, 11B and 19F

• NMR [39] (Scheme 2). Potassium allenyltrifluoroborate (4) is a crystalline solid and despite several microwave promoted reactions can be conducted without the use of solvents, the propargylation reaction using 2-naphthaldehyde and 4 under the previously optimized conditions gave the desired product in

Fluorinated maleimide-substituted porphyrins and chlorins: synthesis and characterization

• Valentina A. Ol’shevskaya,
• Elena G. Kononova and
• Andrei V. Zaitsev

Beilstein J. Org. Chem. 2019, 15, 2704–2709, doi:10.3762/bjoc.15.263

• ) or Ni(II) with N-propargylmaleimide via the CuAAC click reaction to afford fluorinated porphyrin–triazole–maleimide conjugates. New maleimide derivatives were isolated in reasonable yields and identified by UV–vis, 1H NMR, 19F NMR spectroscopy and mass-spectrometry. Keywords: chlorin; maleimide

• was transformed into the corresponding maleimide 12 in 25% yield on the reaction with maleic anhydride according to the standard procedure. Chlorin 12 was metalated with Zn(OAc)2/CHCl3/MeOH giving chlorin 13 in 92% yield. (Scheme 2). All prepared compounds have been structurally identified by 1H, 19F

• NMR, IR and UV–vis absorption spectra (see Supporting Information File 1). Conclusion In this work, we developed a facile protocol for the preparation of new porphyrin and chlorin conjugates with maleimide entities which were synthesized in reasonable isolated yields and fully characterized with NMR

Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

• Nadezhda S. Demina,
• Nikita A. Kazin,
• Nikolay A. Rasputin,
• Roman A. Irgashev and
• Gennady L. Rusinov

Beilstein J. Org. Chem. 2019, 15, 2678–2683, doi:10.3762/bjoc.15.261

• Crystallographic Data Centre via https://www.ccdc.cam.ac.uk/data_request/cif. Supporting Information File 569: Experimental section and copies of 1H, 13C and 19F NMR spectra of new compounds. Supporting Information File 570: Crystal data of 7d. Acknowledgements This study was supported by the Russian Foundation

1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds

• Vito A. Fiore,
• Chiara Freisler and
• Gerhard Maas

Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253

• triphenylphosphane and N-triflyl-propiolanilide 1a in dichloromethane yielded a product mixture, from which only N-phenyltriflylamide (HN(Ph)Tf; 19F NMR: δ −76.5 ppm rel. to C6F6) could be extracted, the remainder being undefined oligomeric/polymeric material. However, when an N-triflylpropiolamide 1a–e (1.03 molar

Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms

• A. Lennart Schleper,
• Mariano L. Bossi,
• Vladimir N. Belov and
• Stefan W. Hell

Beilstein J. Org. Chem. 2019, 15, 2344–2354, doi:10.3762/bjoc.15.227

• DAE 4 could not be isolated by column chromatography on regular silica gel. Instead, monoiodide 4 was obtained in 14% yield as colorless solid after preparative HPLC on a reversed phase (C18) column and lyophilization. The constitution and structure of 4 was confirmed by HRMS, 1H and 19F NMR

• closed form (formed by handling in the lab not fully protected from light) were detected by HPLC (Figure S33 in Supporting Information File 1). The constitution, structures, and purities of the final products were confirmed by HRMS, 1H and 19F NMR spectroscopy, as well as analytical HPLC. Saponification

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene

• Luna Kono,
• Yuma Nakagawa,
• Ayako Fujimoto,
• Ryo Nishimura,
• Yohei Hattori,
• Toshiki Mutai,
• Nobuhiro Yasuda,
• Kenichi Koizumi,
• Satoshi Yokojima,
• Shinichiro Nakamura and
• Kingo Uchida

Beilstein J. Org. Chem. 2019, 15, 2204–2212, doi:10.3762/bjoc.15.217

• were used without further purification. Melting points were determined on a Yanaco MP-500D melting point apparatus and are uncorrected. 1H (400 MHz), 13C (100 MHz) and 19F NMR (376 MHz) spectra were recorded on a JEOL JNM-400 spectrometer at ambient temperature. The splitting patterns are designated as

• , 123.9, 123.0, 122.5, 122.2, 121.7, 121.2, 119.4, 117.5, 113.2, 111.0, 55.5, 14.7, 14.77; 19F NMR (376 MHz, CDCl3, ppm) δ −113.1 (s, 2F), −113.3 (s, 2F), −135.0 (s, 2F); HRMS (MALDI–TOF) m/z: calcd for C35H24F6N2OS2, 666.1234; found, 666.1229. Diarylethene (1o) To 5 mL of dichloromethane anhydrous

• , 142.8, 142.6, 142.1, 141.4, 137.7, 133.4, 130.1, 129.2, 129.2, 128.2, 126.3, 125.9, 125.9, 125.8, 125.8, 124.6, 123.7, 122.5, 121.5, 120.7, 119.2, 117.9, 117.0, 116.1, 107.3, 14.7, 14.7; 19F NMR (376 MHz, CDCl3, ppm) δ −113.1 (s, 2F), −113.3 (s, 2F), −135.0 (s, 2F); HRMS (MALDI–TOF) m/z: calcd for

Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts

• Kenta Tanaka,
• Yuta Tanaka,
• Mami Kishimoto,
• Yujiro Hoshino and
• Kiyoshi Honda

Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208

• ), coupling constants, integration. 13C NMR spectra were recorded on a Bruker DRX-500 (126 MHz) or a JEOL JNM ECA-500 (126 MHz) spectrometer with complete proton decoupling. Chemical shifts are reported in ppm with the solvent resonance as the internal standard (CDCl3: δ 77.0). 19F NMR spectra were recorded

• , 6H); 13C NMR (126 MHz, CDCl3) δ 168.3. 165.5. 165.2. 147.8. 142.2. 127.2. 127.0. 125.6. 116.9. 101.8. 101.4. 57.7. 56.7; 19F NMR (376 MHz, CDCl3) δ −81.3; IR (ATR): 1585, 1219, 1143, 1026, 634 cm−1; HRMS (ESI+) m/z: [M]+ calcd for C23H21O4S, 393.1155; found, 393.1171; anal. calcd for C24H21F3O7S2: C

• Hz, 1H), 6.93 (dd, J = 7.1, 1.1 Hz, 1H), 6.43 (d, J = 2.2 Hz, 2H), 4.15 (s, 6H), 2.96 (s, 6H); 13C NMR (126 MHz, CDCl3) δ 168.4, 165.2, 164.7, 147.6, 140.7, 132.1, 132.0, 128.2, 127.5, 126.4, 125.9, 125.0, 124.4, 121.3, 117.6, 102.0, 101.5, 57.7, 56.6; 19F NMR (376 MHz, CDCl3) δ −81.3; IR (ATR): 1593

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• , 146.58; 19F NMR (DMSO-d6) δ 148; HRMS (ESIMS) m/z: [M2+]; calcd. for C12H16N42+ 216.1364 108.0682; found, 108.0683. 1,4-Diacetyl)-1,2,3,4-tetrahydropyrazino[2,3-g]quinoxaline (9): 1,2,3,4-Tetrahydropyrazino[2,3-g]quinoxaline (3, 500 mg, 2.68 mmol) was added to 20 mL of acetic anhydride and the mixture

Synthesis and anion binding properties of phthalimide-containing corona[6]arenes

• Meng-Di Gu,
• Yao Lu and
• Mei-Xiang Wang

Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193

• = 6.4 Hz, 6H); 19F NMR (376 MHz, DMSO-d6, 25 °C) δ 59.8; 13C NMR (101 MHz, MeCN-d3, 25 °C) δ 167.1, 164.5, 154.8, 145.0, 144.2, 131.2, 125.9, 124.7 (q,1J(C, F) = 271.6 Hz), 124.5, 120.9 (q, 2J(C, F) = 31.8 Hz), 117.1, 36.5, 35.5, 28.2; IR (KBr, cm−1) ν: 3372, 3080, 2937, 1775, 1717, 1603, 1545, 1382

Fluorine-containing substituents: metabolism of the α,α-difluoroethyl thioether motif

• Andrea Rodil,
• Alexandra M. Z. Slawin,
• Nawaf Al-Maharik,
• Ren Tomita and
• David O’Hagan

Beilstein J. Org. Chem. 2019, 15, 1441–1447, doi:10.3762/bjoc.15.144

• 19F NMR spectrum consistent with non-equivalence of the fluorines, immediately indicative of sulfoxide formation. Isolation and subsequent 1H and 19F NMR analyses as well as high-resolution mass spectrometry secured the identity of these metabolites as sulfoxides 6 and 7 and sulfone 8. The structure

• naphthalene ring, as summarised in Scheme 3. These metabolites were isolated by reversed-phase HPLC and characterised by 1H and 19F NMR and mass spectrometry. This identified sulfoxides 11 and 12 as the major metabolites and a trace amount of a minor sulfone which had the general structure 13 as determined by

• hydrolytic lability of the analogous oxygen ethers. By way of example α,α-difluoroethyl ether 14 [18] was incubated with cultures of C. elegans under the standardised conditions, as illustrated in Scheme 4. 19F NMR of the extract indicated a trace of residual starting material with one major metabolite which

Stereo- and regioselective hydroboration of 1-exo-methylene pyranoses: discovery of aryltriazolylmethyl C-galactopyranosides as selective galectin-1 inhibitors

• Alexander Dahlqvist,
• Axel Furevi,
• Niklas Warlin,
• Hakon Leffler and
• Ulf J. Nilsson

Beilstein J. Org. Chem. 2019, 15, 1046–1060, doi:10.3762/bjoc.15.102

• stated in the procedure. NMR spectra were collected on a Bruker Ultrashield Plus/Avance II 400 MHz spectrometer. 1H NMR spectra were recorded at 400 MHz and 13C NMR spectra at 100 MHz with residual solvent signals as references. 19F NMR spectra were recorded at 376 MHz. Stereochemistry was assigned

• = 11.4 Hz, 7.2 Hz, 1H, H7), 3.69 (dd, J = 11.5 Hz, 4.6 Hz, 1H, H7), 3.60–3.49 (m, 4H); 13C NMR (100 MHz, CD3OD) δ 161.6, 146.2, 127.4, 127.3, 126.6, 122.4, 115.5, 115.3, 79.0, 78.6, 74.7, 69.4, 68.4, 61.5, 51.6; 19F NMR (376 MHz, CD3OD) δ −115.54; HRMS (m/z): [M + H]+ calcd for 340.1306; found, 340.1309

• ), 3.90 (dd, J = 2.9 Hz, 0.9 Hz, 1H, H5), 3.79 (dd, J = 11.2 Hz, 6.9 Hz, 1H, H7), 3.70 (dd, J = 11.6 Hz, 4.71 Hz, 1H, H7), 3.60–3.48 (m, 4H); 13C NMR (100 MHz, CD3OD) δ 164.5, 146.2, 132.9, 130.5, 122.9, 121.1, 114.4, 111.9, 78.9, 78.7, 74.7 69.4, 68.4, 61.5, 51.5; 19F NMR (376 MHz, CD3OD) δ −114.83; HRMS

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• nature of the halogen bond assembly. The crystal lattice of 1 contains two structurally different dimeric assemblies A and B, formally resulting in the mixture of a capsular dimer and a dimeric pseudo-capsule. 1H and 19F NMR analyses supports the existence of these halogen-bonded complexes and enhanced

• –NH2 protons of the NARXs are expected [32][33]. Additionally, NARXs are also known to cooperatively bind small guest molecules such as mono- and diamides [42][43]. Consequently, we used 1H and 19F NMR spectroscopy to study the XB assemblies formed between Hex-NARBr 1 and 1,4-diiodooctafluorobutane (5

• acetonitrile. The 1H and 19F NMR spectra of all these samples were recorded at 298 K and analyzed. In the 19F NMR analyses, the fluorine signals of the XB donor DIOFB were monitored. In all cases, minor upfield shifts of the fluorines on the terminal carbons were observed (0.12 ppm in 1·DIOFB, 0.13 ppm in 1

Conformational signature of Ishikawa´s reagent using NMR information from diastereotopic fluorines

• Laize A. F. Andrade,
• Lucas A. Zeoly,
• Rodrigo A. Cormanich and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2019, 15, 506–512, doi:10.3762/bjoc.15.44

• enhance the fluoride character of the fluorine involved in such interaction. Because of the negative charge on the fluorine in the resonance structure derived from the generalized anomeric effect, a shielding effect is expected for this fluorine. The 19F NMR assignment of the diastereotopic fluorines was

• the respective Newman projections indicating the two key rotatable bonds. Expansion of the 1H and 19F NMR spectra in the region of CHF and CF2, in C6D12 and C5D5N solvents. The 19F chemical shifts were assigned taking into consideration the signal split patterns, coupling constants and possible

Unexpected loss of stereoselectivity in glycosylation reactions during the synthesis of chondroitin sulfate oligosaccharides

• Teresa Mena-Barragán,
• José L. de Paz and
• Pedro M. Nieto

Beilstein J. Org. Chem. 2019, 15, 137–144, doi:10.3762/bjoc.15.14

• leads to the selective formation of the desired 1,2-trans glycosidic linkages and can be easily removed at the end of the synthesis [7][8][36][42]. Moreover, 19F NMR experiments can be employed to assist in the analysis and monitoring of reactions involving N-TFA building blocks. First, we describe the

• -2C (δ = 4.50 ppm in 14α; δ = 3.52–3.43 ppm in 14β). The value of the coupling constant J1,2 in ring C confirmed the configuration of the new glycosidic linkage (J1,2 = 3.2 Hz in 14α; J1,2 = 8.2–8.5 Hz in 14β). 19F NMR spectra also showed clear differences in the chemical shifts for the

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• at 400 MHz; 13C NMR at 101 MHz) or a JEOL–ECA500 spectrometer (19F NMR at 471 MHz). Chemical shifts are reported in ppm relative to the internal standard signal (0 ppm for Me4Si in CDCl3) for 1H NMR and the solvent signal (77.16 ppm for CDCl3) for 13C NMR. Data are presented as follows: chemical

• , 24.34, 24.29; 19F NMR (471 MHz, CDCl3) δ −126.3; HRMS–APCI+ (m/z): [M + H]+ calcd for C47H54FN2O8, 793.3859; found, 793.3859. Synthesis of bis(salen) (R,R,S,S)-8: The crude product was obtained from (S,S)-1,2-cyclohexanediamine monohydrochloride (28 mg, 0.19 mmol), 3-tert-butyl-5-fluoro-2

• ), 72.8, 72.0, 35.1, 35.0, 33.2, 33.0, 29.3, 29.1, 24.35, 24.29; 19F NMR (471 MHz, CDCl3) δ −126.3; HRMS–APCI+ (m/z): [M + H]+ calcd for C64H77F2N4O8+, 1067.5704; found, 1067.5697. Synthesis of bis(salen) (R,R,R,R)-8: The crude product was obtained from (R,R)-1,2-cyclohexanediamine monohydrochloride (0.10

Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex

• Henrike Ehrhorn,
• Janin Schlösser,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2018, 14, 2425–2434, doi:10.3762/bjoc.14.220

• from [NaW2Cl7(THF)5] [86]. The 13C and 19F NMR spectra are also consistent with literature values. Crystals of W2F3 suitable for X-ray diffraction analysis were obtained upon cooling a saturated pentane solution to −40 °C. Unfortunately, the crystal structure suffers from severe disorder. Each tungsten

• -like reaction, the W≡W bond is cleaved, with 2-butyne forming as a side product. Following this reaction by 1H and 19F NMR spectroscopy revealed fast and selective formation of WPhF3, and after 14 minutes, most of the starting material W2F3 was already consumed, with full conversion observed after 28

• minutes. Selected 19F NMR spectra can be found in Figure S7 of Supporting Information File 1. The 1H NMR spectrum of WPhF3 displays two multiplets in the aromatic region for the benzylidyne hydrogen atoms and one singlet for the methyl groups of the trifluoro-tert-butoxy ligand at 1.65 ppm. In the 13C NMR

Practical tetrafluoroethylene fragment installation through a coupling reaction of (1,1,2,2-tetrafluorobut-3-en-1-yl)zinc bromide with various electrophiles

• Ken Tamamoto,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 2375–2383, doi:10.3762/bjoc.14.213

• 1.5 years in the refrigerator [35]. In order to examine the stability of 2-Zn in more detail, we quantitatively evaluated the thermal stability of 2-Zn under various temperature conditions (Figure 2). After a given duration, the recovery yield of 2-Zn was determined by 19F NMR analysis using an

• for Cu(I)-catalyzed cross-coupling reaction of 2-Zn with benzoyl chloride (5a). Supporting Information Supporting Information File 332: Experimental procedures, characterization data (1H, 13C, 19F NMR, IR and HRMS), copies of 1H, 13C and 19F NMR spectra.

Determining the predominant tautomeric structure of iodine-based group-transfer reagents by ¹⁷O NMR spectroscopy

• Nico Santschi,
• Cody Ross Pitts,
• Benson J. Jelier and
• René Verel

Beilstein J. Org. Chem. 2018, 14, 2289–2294, doi:10.3762/bjoc.14.203

• HCl compound 4a afforded an isolable iodonium-type structure [20]. Although this activation can be conveniently followed by 19F NMR spectroscopy with 4a resonating at −40.1 ppm and the fully protonated “iodonium” congener 4c at −20 ppm [1], this technique provides no indication on how to best

• then subjected to spectroscopic analysis. A 19F NMR chemical shift of −23.2 ppm was obtained, thereby confirming the presence of 4c. However, under these strongly acidic and activating conditions, the compound is unstable over a prolonged period of time (12 h). During the acquisition of the 17O NMR

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• -oxyimidation product 3a from styrene 1a and N-hydroxyimide 2a a. Supporting Information Supporting Information File 213: Experimental procedures, characterization data, copies of 1H, 13C and 19F NMR spectra, copies of HRMS and FT-IR spectra and the ORTEP diagram and X-ray data for compound 3ca. Supporting