Hypervalent iodine-mediated Ritter-type amidation of terminal alkenes: The synthesis of isoxazoline and pyrazoline cores

• Sang Won Park,
• Soong-Hyun Kim,
• Jaeyoung Song,
• Ga Young Park,
• Darong Kim,
• Tae-Gyu Nam and
• Ki Bum Hong

Beilstein J. Org. Chem. 2018, 14, 1028–1033, doi:10.3762/bjoc.14.89

• Innovation Foundation (DGMIF), 80 Cheombok-ro, Dong-gu, Daegu, Republic of Korea 10.3762/bjoc.14.89 Abstract Hypervalent iodine-mediated olefin functionalization provides a rapid gateway towards accessing both various heterocyclic cores and functional groups. In this regard, we have developed a Ritter-type

• (see Supporting Information File 1, Table S1). Upon optimization with various oxidants and additives screened, it was found that a Lewis acid additive can promote the olefin heterofunctionalization via a Ritter-type amidation using acetonitrile as both the solvent and the amine source. Interestingly

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• dehydrogenative coupling reactions [34][35] and for olefin hydroamidations [36] (Scheme 1d–f). For potential applications of ferrocene derivatives as redox mediators or SET reagents, it is crucial to adjust the electrochemical potential to the potential of the substrate. The electrochemical potential of the

Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of vicinal-dichlorides and chlorodienes

• Zhensheng Zhao and
• Graham K. Murphy

Beilstein J. Org. Chem. 2018, 14, 796–802, doi:10.3762/bjoc.14.67

• efficient new process for the chlorination of substituted phenylallene derivatives using the hypervalent iodine reagent 1-chloro-1,2-benziodoxol-3-one (1b). The reactions disclosed here represent the first report of a regioselective chlorination of phenylallenes, in which the 2,3-allene olefin undergoes

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• nanoparticles (DSN) have been shown to be highly efficient in the catalysis of olefin hydrogenation and in Suzuki coupling reactions [98][99]. Ornelas et al. entrapped a palladium catalyst with dendrimers containing triazole groups (DSN) (Figure 6) [100]. The aim here was to provide a platform to perform

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

• different functional groups. But the reaction was sensitive to the steric hindrance of the olefin substrates, and 2-substituted terminal alkenes or internal (including cyclic) alkenes were not applicable to this protocol. A mechanistic study showed that the reaction may proceed through a Heck-like four

• -membered-ring transition state. Note that the presence of an olefin moiety in the product promised further conversion to other types of CF3-containing molecules. Later, the group of Wang [50] employed cheap copper chloride as the catalyst and a hypervalent iodine(III) reagent 1j as both the oxidant and the

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• photocatalytic cycle. The addition of the sulfonyl radical to the olefin yields a β-sulfonyl radical intermediate. The final difunctionalized product can be generated by two possible pathways: Either the radical intermediate is oxidized to the respective cation by closing the catalytic cycle and combines with a

Acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with alcohols

• Katrina Tait,
• Alysia Horvath,
• Nicolas Blanchard and
• William Tam

Beilstein J. Org. Chem. 2017, 13, 2888–2894, doi:10.3762/bjoc.13.281

• of the olefin can lead to a wide variety of products often in a single step, which is synthetically useful to create many highly substituted products with different stereochemical outcomes (Scheme 2). There are many reported examples in the literature of the modification of the alkene component which

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

• was demonstrated albeit in moderate yields. The yields of the trifluoromethylation of alkenyltrifluoroborates strongly depended on the substitution of the olefin (Scheme 55). Simultaneously, Dubbaka and co-workers reported the trifluoromethylation of aryl-, heteroaryl-, and vinyltrifluoroborates with

Synthesis of ergostane-type brassinosteroids with modifications in ring A

• Vladimir N. Zhabinskii,
• Darya A. Osiyuk,
• Yuri V. Ermolovich,
• Natalia M. Chaschina,
• Tatsiana S. Dalidovich,
• Miroslav Strnad and
• Vladimir A. Khripach

Beilstein J. Org. Chem. 2017, 13, 2326–2331, doi:10.3762/bjoc.13.229

• cyclic thiocarbonate 15 as a key reaction step gave the expected Δ2-olefin 16 in an excellent yield (Scheme 2). Subsequent deacetylation of 16 then afforded 24-episecasterol (17). An alternative procedure to Δ2-steroids was applied for the preparation of the B-ring lactone derivative 21 (Scheme 3). The

• mesylation of diol 18 produced dimesylate 19, which was treated with zinc dust and sodium iodide in refluxing DMF (Tipson–Cohen reaction [16]) to give, after deacetylation, B-lactone olefin 21 in 96% yield. 2α,3α- and 2β,3β-epoxides of type 4 and 5 Olefins of type 3 are evident intermediates for the

• isomeric 2,3-epoxides 22 and 24 with a 7-membered B-ring lactone was accomplished starting from the olefin 21 (Scheme 4). The reaction of peracids with Δ2-steroids possessing a six-membered B ring is known to proceed from the less hindered side of the molecule and results in the formation of 2α,3α-epoxides

Synthesis of 2-aminosuberic acid derivatives as components of some histone deacetylase inhibiting cyclic tetrapeptides

• Shital Kumar Chattopadhyay,
• Suman Sil and
• Jyoti Prasad Mukherjee

Beilstein J. Org. Chem. 2017, 13, 2153–2156, doi:10.3762/bjoc.13.214

• known [30][31][32][33]. However, all attempts of CM reaction of 11 with the olefin 13d proved to be futile, a major problem being the inadequate solubility of the olefin in the reaction solvents tried, e.g., dichloromethane, dichloroethane, benzene, toluene etc. The solubility problem may be avoided by

• carried out in a manner as described in [36]. Grubb’s second generation catalyst 12 (10 mg, 0.012 mmol, 2.5 mol %) was added to a stirring solution of olefin 11 (130 mg, 0.50 mmol) in dry DCM (1 mL) and then a solution of the appropriate electron-deficient olefin 13 (1.5 mmol) in dry DCM (1 mL) was added

Synthesis of substituted Z-styrenes by Hiyama-type coupling of oxasilacycloalkenes: application to the synthesis of a 1-benzoxocane

• James R. Vyvyan,
• Courtney A. Engles,
• Scott L. Bray,
• Erik D. Wold,
• Christopher L. Porter and
• Mikhail O. Konev

Beilstein J. Org. Chem. 2017, 13, 2122–2127, doi:10.3762/bjoc.13.209

• NMR spectra of the crude reaction mixtures from these experiments, so we were reluctant to increase the reaction temperature further. We also hydrogenated the conjugated olefin of 15 to increase the flexibility of the tether, in case the conformational constraint was actually hindering the cyclization

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• . Importantly catalytic application of these mechano-synthesized complexes are also explored. Friščić and co-workers recently reported an efficient mechanochemical approach towards Ru-based Hoveyda–Grubbs catalyzed olefin metathesis, cross-metathesis and ring-closing metathesis reactions (Scheme 49) [181

• complex [180]. Mechanochemical Ru-catalyzed olefin metathesis reaction [181]. Rhodium(III)-catalyzed C–H bond functionalization under mechanochemical conditions [182]. Mechanochemical Csp2–H bond amidation using Ir(III) catalyst [183]. Mechanochemical Rh-catalyzed Csp2–X bond formation [184

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• tested reaction conditions. Additionally, the heterocyclic alkene 4-vinylpyridine (2b) was used as a coupling partner in the presence of aryl bromides 1a–d. Even though olefin 2b was shown to be slightly less reactive than styrene (2a), the heteroaromatic coupling products were afforded in excellent

• yields (entries 9–12, Table 2). By this methodology, new heteroaromatic olefins 11–13 were synthesized. The reaction with the symmetric gem-substituted olefin 1,1-diphenylethylene (2c) and 4-bromoacetophenone (1a) gave the trisubstituted olefin 15 in moderate yield (40%, entry 13, Table 2) [56]. On the

• with a magnetic stirring bar, aryl halide 1a–h (0.25 mmol), K2CO3 (0.5 mmol), olefin 2a–d (0.3 mmol), ethanol (0.5 mL) and water (to obtain a total volume of 2 mL taking into account the volume of Pd NPs solution) were added. Finally, the required volume of the Pd NPs dispersion was added. Then, the

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• principal approaches have been used to establish the 12-membered macrolactone ring, namely (1) ring-closure by macrolactonization, the approach followed by Kishi, Negishi and Aggarwal, or (2) ring-closing olefin metathesis (RCM) to form the C8–C9 double bond, which is part of Burkart’s and Altmann’s

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

• Yonglei Du,
• Jian Li,
• Kerong Chen,
• Chenglin Wu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

• -catalyzed Michael addition/intramolecular silyl nitronate-olefin cycloaddition (ISOC)/fragmentation sequence to produce highly enantioenriched spirocyclopentaneoxindoles containing an oxime functional group from easily accessible 3-allyl-substituted oxindoles and nitroolefins, which has received wide

Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

• Adesh Kumar Singh,
• Varsha Tiwari,
• Kunj Bihari Mishra,
• Surabhi Gupta and
• Jeyakumar Kandasamy

Beilstein J. Org. Chem. 2017, 13, 1139–1144, doi:10.3762/bjoc.13.113

• , oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide. Keywords: monosaccharides; oxidation; sulfones; sulfoxides; thioglycosides; urea–hydrogen peroxide; Introduction Organosulfur compounds such as sulfides, sulfoxides and sulfones are useful intermediates

• (UHP). Glycosyl sulfoxides were achieved using 1.5 equiv of UHP at 60 °C while sulfones were achieved using 2.5 equiv of UHP at 80 °C. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the sulfide oxidation. Optimization of reaction conditions.a Controlled

Total syntheses of the archazolids: an emerging class of novel anticancer drugs

• Stephan Scheeff and
• Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

• . However, the similar biological potency of archazolids A and B as well as the archazolid B isomer archazolid F, which bears a 3,4- instead of the 2,3-alkene, suggest that the C2-olefin may not be essential for the biological potency. Accordingly, the group of O‘Neil and co-workers has been targeted

Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydroanhydrocycloheximides

• Li Yang,
• Ping Wu,
• Jinghua Xue,
• Huitong Tan,
• Zheng Zhang and
• Xiaoyi Wei

Beilstein J. Org. Chem. 2017, 13, 1039–1049, doi:10.3762/bjoc.13.103

• keto carbonyl (δC 202.6), two amide carbonyls (δC 175.5, 175.7), a trisubstituted olefin (δH 6.65; δC 134.2, 151.9), two methyls (δH 1.72, 1.16; δC 14.5, 20.3), four aliphatic methines with one being oxygenated (δH 4.26; δC 67.3), and four methylenes. Analysis of the 1H,1H-COSY and HMBC spectra, in

• and carbon signals resembled those of compound 1 except for replacement of the resonances for the hydroxymethine at Cα and the aliphatic methine at C6 in 1 by the signals for an additional trisubstituted olefin [δH 6.59; δC134.6 (CH), 136.1 (C) in 2 and δH 5.86; δC137.1 (CH), 136.2 (C) in 3

A strategic approach to [6,6]-bicyclic lactones: application towards the CD fragment of DHβE

• Tue Heesgaard Jepsen,
• Emil Glibstrup,
• François Crestey,
• Anders A. Jensen and
• Jesper Langgaard Kristensen

Beilstein J. Org. Chem. 2017, 13, 988–994, doi:10.3762/bjoc.13.98

• the C ring by an intramolecular Mizoroki–Heck cross-coupling reaction from a Z-configured olefin which would be crucial to the stereochemical outcome of the Heck cyclization event. We envisioned a Z-stereoselective synthesis of a vinyl halide [17] which should secure the desired E-stereochemistry for

• olefin occurred at higher temperatures. Subjecting 25 to the standard conditions for the final 6π-electrocyclization (toluene, THF, or DME) at 80–150 °C either led to no conversion of the starting material or complete decomposition at elevated temperatures. We speculated that the low solubility of

Synthesis of ribavirin 2’-Me-C-nucleoside analogues

• Fanny Cosson,
• Aline Faroux,
• Jean-Pierre Baltaze,
• Jonathan Farjon,
• Régis Guillot,
• Jacques Uziel and
• Nadège Lubin-Germain

Beilstein J. Org. Chem. 2017, 13, 755–761, doi:10.3762/bjoc.13.74

• 13b with DAST was performed at −20 °C and afforded the desired fluorinated derivative 14 (24%) along with two elimination products, the exocyclic olefin 15 (16%) and the corresponding endocyclic one 16 (20%). As it was impossible to separate 15 from 14 at this stage, the mixture 14/15 was deprotected

Biosynthetic origin of butyrolactol A, an antifungal polyketide produced by a marine-derived Streptomyces

• Enjuro Harunari,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2017, 13, 441–450, doi:10.3762/bjoc.13.47

• -like structures [4][5][6][7][8]. Butyrolactol A (1) is an antifungal polyketide first isolated from Streptomyces rochei S785-16 [9] (Figure 1). The left half of 1 is the hydrophobic unconjugated tetraene system including one Z-olefin with a terminal tert-butyl group, whereas the hydrophilic polyol

(Z)-Selective Takai olefination of salicylaldehydes

• Stephen M. Geddis,
• Caroline E. Hagerman,
• Warren R. J. D. Galloway,
• Hannah F. Sore,
• Jonathan M. Goodman and
• David R. Spring

Beilstein J. Org. Chem. 2017, 13, 323–328, doi:10.3762/bjoc.13.35

• formed bond to give the (E)-configured olefin, (E)-2 [5]. The minor (Z)-configured product, (Z)-2, presumably results from the reaction through a less favourable transition state which is nearly identical to 5 but differs in that either the R1 substituent originating from the aldehyde or the X

• observed (Z)-olefin products, (Z)-47. Whilst further experimental data is required in order to bolster this hypothesis, our proposed mechanism should act as a starting point for future detailed mechanistic investigations. Our observation that this alternative pathway is favoured by electron-withdrawing

• discussed above. Conclusion Following our observation of unusually high levels of (Z)-olefin product following Takai olefination of a particular aromatic substrate, systematic screening of related substrates revealed the characteristics a substrate should possess in order to lead to (Z)-selective Takai

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• second part of their work, they developed adequate conditions to carry out the decyanation reaction without olefin isomerization [18]. They explored several methods for the preparation of 12-butyltricosa-1,22-diene 3 (R = n-C4H9). The reaction was carried out in a slurry of K/Al2O3 in hexane, hexane

• /toluene (1:1) and toluene giving 20%, 63% and 75% of olefin isomerization (from NMR and GC), respectively, for each solvent [34]. This isomerization was attributed to the translocation of the tertiary radical intermediate to a more stable allyl radical leading to the double bond migration. This

• rearrangement was avoided using K/Ph3CH in hexane/ether (3 R = n-C4H9, 41% yield) or K/HMPA/t-BuOH in ether (3 R = n-C4H9, 99% yield). The latter optimized conditions allow the decyanation of alkylcyano α,ω-dienes 2 in quantitative yields with no detection of olefin isomerization (Scheme 3). Radical

Efficient access to β-vinylporphyrin derivatives via palladium cross coupling of β-bromoporphyrins with N-tosylhydrazones

• Vinicius R. Campos,
• Ana T. P. C. Gomes,
• Anna C. Cunha,
• Maria da Graça P. M. S. Neves,
• Vitor F. Ferreira and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2017, 13, 195–202, doi:10.3762/bjoc.13.22

• two germinal protons H-2’ of the olefin unit appear as two doublets (J = 1.3 Hz) at 5.81 and 5.56 ppm. The value of the coupling constant and the unique correlation of these two protons with a single carbon (115.5 ppm) observed in HSQC spectra corroborates the proposed structure. The HRMS–ESI

Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions

• Michal Medvecký,
• Igor Linder,
• Luise Schefzig,
• Hans-Ulrich Reissig and
• Reinhold Zimmer

Beilstein J. Org. Chem. 2016, 12, 2898–2905, doi:10.3762/bjoc.12.289

• tendency of this olefin to polymerize under the conditions applied. Consequently, the change of the olefin component from the methyl to the tert-butyl ester allowed the preparation of the corresponding coupling product syn-14 in significantly better yield. The use of dehydroamino acids such as olefin 16