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Search for "iodine" in Full Text gives 484 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

  • Jorge de Lima Neto and
  • Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

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  • alcohol 64. The formation of the double bond from alcohol 64 proved to be problematic, thus, replacement of the hydroxy group by iodine [47] followed by dehydrohalogenation using an excess of KF afforded methyl combretastatin D-2 (28) in 87% yield after two steps (Scheme 11). The authors also described a
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Published 29 Mar 2023

Synthesis and reactivity of azole-based iodazinium salts

  • Thomas J. Kuczmera,
  • Annalena Dietz,
  • Andreas Boelke and
  • Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

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  • imidazoiodaziniums, we show highly delicate post-oxidation functionalizations retaining the hypervalent iodine center. Keywords: building block; heterocycles; hypervalent compounds; iodonium salts; one-pot synthesis; Introduction The chemistry of hypervalent iodine compounds, in particular aryl-λ3-iodanes, is
  • chemistry of hypervalent iodine species in all their variety, particularly those containing N-heterocycles either as tethered stabilizing ligands or as an inclusive part of a cyclic iodonium salt [26][27][28][29][30][31]. We prepared five-membered, N-heterocycle-containing iodoliums 2 and investigated their
  • novel azoiodazinium salts (Figure 3). An N4–I1 distance of 2.540 Å with a typical T-shape structure (N4–I1–C1 angle 185.74°) implies a significant interaction between the N-heterocycle and the iodine atom for the ortho-pyrazole-substituted derivative 5bb [35]. However, the presence of an ortho-methyl
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Published 16 Mar 2023

Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr4/PPh3 and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

  • Christian Schumacher,
  • Jas S. Ward,
  • Kari Rissanen,
  • Carsten Bolm and
  • Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

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  • visualized by their fluorescence under UV–lamp (λ = 245 and 365 nm) or staining with iodine vapor or 15% H2SO4 or KMnO4 solution, or Ce(IV)SO4 in H2SO4. Melting points were determined on a Gallenkamp apparatus UK and are uncorrected. NMR spectra were recorded on a Bruker 600 MHz spectrometer at the central
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Published 27 Jan 2023

Two-step continuous-flow synthesis of 6-membered cyclic iodonium salts via anodic oxidation

  • Julian Spils,
  • Thomas Wirth and
  • Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 27–32, doi:10.3762/bjoc.19.2

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  • Friedel–Crafts alkylation followed by an anodic oxidative cyclization yielded a defined set of cyclic iodonium salts in a highly substrate-dependent yield. Keywords: electrochemistry; flow chemistry; hypervalent compounds; iodine; oxidation; Introduction Hypervalent iodine compounds (HVI) are well
  • electrochemistry is a highly economical tool that avoids chemical oxidants for synthesizing hypervalent iodine reagents [30]. Iodoarenes are suitable and well-established mediators in either in- or ex-cell electrochemical processes [31][32][33][34][35][36]. Nonetheless, HVIs, DIS and CDIS have been generated by
  • improved the overall yield to 43%. Finally, we investigated a variety of substituted benzyl acetates 3 (Figure 1). Substitutions para to the iodine led with F- and Cl-derivatives 1b and 1c to strongly diminished yields of 15% and 26%, respectively, due to expected lower yields in the Friedel–Crafts step
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Published 03 Jan 2023

Combining the best of both worlds: radical-based divergent total synthesis

  • Kyriaki Gennaiou,
  • Antonios Kelesidis,
  • Maria Kourgiantaki and
  • Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

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  • reported the flow-controlled divergent synthesis of aporphine and morphinandienone alkaloids based on biomimetic common scaffolds (e.g., 180) using hypervalent iodine(III) reagents. Capitalizing on previously reported mechanistic investigations, they assumed that 180 can rearrange to glaucine (183) through
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Published 02 Jan 2023

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

  • Elena R. Lopat’eva,
  • Igor B. Krylov,
  • Dmitry A. Lapshin and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

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  • /peroxide, quinones, and iodine(I/III) compounds are the most developed catalyst types which are covered here. Keywords: CH-functionalization; free radicals; hypervalent iodine; N-oxyl radicals; redox-active molecules; Introduction Organocatalysis can be defined as catalysis by small organic molecules
  • classified according to the catalytically active species or key intermediates: N-oxyl radicals, oxoammonium cations, amine cation radicals, thiyl radicals, quinones, dioxiranes and oxaziridines, hypervalent iodine compounds, etc. However, some examples of organocatalyzed oxidative processes, in which an
  • the key factor for the high chemoselectivity. Hypervalent iodine catalysis Effective hypervalent iodine(III)-catalyzed processes (for example, oxidative double C=C bond functionalization, oxidative cyclizations, CH-functionalization of carbonyl compounds, etc.) employing mainly peroxoacids or electric
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Published 09 Dec 2022

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

  • Arisu Koyanagi,
  • Yuki Murata,
  • Shiori Hayakawa,
  • Mio Matsumura and
  • Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

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  • reaction of o-alkoxythiobenzamides with iodine in the presence of sodium hydride as the base [11]. Sugita et al. reported an unstable iodoalkyne, pentafluoro(iodoethynyl)benzene, which catalyzed the cyclization of thioamides with 2-aminophenol [12]. These approaches have some drawbacks, such as low yields
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Published 18 Oct 2022

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

  • Anaïs Rousseau,
  • Guillaume Vincent and
  • Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

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  • coupling revealed the incompatibility of the lactone function; therefore, it was reduced with DIBAL-H then transformed into 19 by a one pot acetalization–desilylation procedure (91:9 mixture of diastereomers) [17]. Hydrozirconation followed by treatment with iodine furnished the target vinyl iodide 20
  • according to reference [18]. A solution of the alkyne 19 (300 mg, 1.80 mmol) dans in anhydrous dichloromethane (4.2 mL) was added dropwise to a suspension of Cp2ZrHCl (696 mg, 2.70 mmol, 1.5 equiv) in anhydrous dichloromethane (9 mL). After stirring at rt for 15 min, a solution of iodine (777 mg, 3.06 mmol
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Published 04 Oct 2022

On drug discovery against infectious diseases and academic medicinal chemistry contributions

  • Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 1355–1378, doi:10.3762/bjoc.18.141

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  • which parts are prone to oxidation/metabolization. A remarkable result, using diluted iodine, was actually reported recently [301]. Concerning another class of “old” drugs, and as depicted in Figure 9 with the (few) structures 49–61, the many generations of β-lactams used in human medicine is certainly
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Published 29 Sep 2022

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH4I

  • Shang-Feng Yang,
  • Pei Li,
  • Zi-Lin Fang,
  • Sen Liang,
  • Hong-Yu Tian,
  • Bao-Guo Sun,
  • Kun Xu and
  • Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

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  • and to determine the possible active intermediates involved, several control experiments were carried out. As shown in Scheme 4, when molecular iodine was employed as oxidant, the desired product 3a was obtained in a 67% yield under otherwise identical conditions (Scheme 4a), but without passing
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Published 15 Sep 2022

A versatile way for the synthesis of monomethylamines by reduction of N-substituted carbonylimidazoles with the NaBH4/I2 system

  • Lin Chen,
  • Xuan Zhou,
  • Zhiyong Chen,
  • Changxu Wang,
  • Shunjie Wang and
  • Hanbing Teng

Beilstein J. Org. Chem. 2022, 18, 1032–1039, doi:10.3762/bjoc.18.104

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  • reducibility of NaBH4. In this work, our goal is to reduce the carbonyl group in N-substituted carbonylimidazoles. The inexpensive NaBH4/I2 system has great attraction because it is more reductive due to the generation of highly reactive BH3–THF by adding iodine to NaBH4 in THF [76][77][78] and the reaction
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Published 17 Aug 2022

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

  • Valentin H. K. Fell,
  • Joseph Cameron,
  • Alexander L. Kanibolotsky,
  • Eman J. Hussien and
  • Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

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  • iodine, anhydrous diethyl ether, 45 °C, 2 h, 3-bromothiophene, [1,3-bis(diphenylphosphino)propane]dichloronickel(II), 45 °C, 14.5 h, 40% [47]; b) n-butyllithium, 2,2,6,6-tetramethylpiperidine, anhydrous tetrahydrofuran, −80 °C, iodomethane, then rt, overnight, 86% [48]; c) n-butyllithium, anhydrous
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Published 01 Aug 2022

The stereochemical course of 2-methylisoborneol biosynthesis

  • Binbin Gu,
  • Anwei Hou and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

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  • . Further conversion by treatment with PPh3, iodine, pyridine, and water [38] gave access to (R)- and (S)-2-methyllinalool (6a and 6b). The materials were subsequently converted into the diphosphates using triethylammonium phosphate and trichloroacetonitrile [39] (Scheme 2). Conversion of enantiomerically
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Published 08 Jul 2022

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

  • Mengjie Wang,
  • Lanping Dang,
  • Wan Xu,
  • Zhiying Ma,
  • Liuliu Shao,
  • Guangxia Wang,
  • Chunli Li and
  • Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

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  • resulted in oxidative photocyclization products with two types of configurations wherein two benzene rings were closed in the same and opposite direction, such as DH-1–3 and 6 (Figure 2). However, after the double oxidative photocyclizations of 5a–c in the presence of iodine and propylene oxide in dry
  • toluene (6 mL), iodine (7.3 mg, 0.028 mmol, 2.0 equiv) and excess propylene oxide were added. The reaction solution was irradiated with a 450 W unfiltered Hg medium-pressure lamp for 1.5 h. The reaction was quenched with saturated Na2SO3 solution (5 mL). The reaction mixture was extracted with CH2Cl2 (3
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Published 08 Jul 2022

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

  • Durbis J. Castillo-Pazos,
  • Juan D. Lasso and
  • Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

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  • solubility of this class of molecules, perfluoroalkyl iodides have a tendency to be weakly soluble in common organic solvents (i.e., ethyl acetate and methanol) rendering their application troublesome [9]. Moreover, the homolysis of the perfluoroalkyl iodide produces iodine radicals that can result in stray
  • , the expansion of our previously reported propiophenone family of reagents was envisioned as suitable alternative to produce a bench stable, organic soluble, and iodine-free perfluroalkylation source. In 2017, our group developed a metal-free and redox-neutral protocol for the photoinduced alkylation
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Published 04 Jul 2022

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

  • Dajana Barišić,
  • Mario Pajić,
  • Ivan Halasz,
  • Darko Babić and
  • Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

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  • PdII-catalyzed iodination of L6–8 was conducted with N-iodosuccinimide (NIS) as the iodine source. The reaction time for the iodination of L6 was the same as for the analogous bromination reaction (Table 2, entry 10). Iodination of L7 and L8 was completed within five and seven hours, respectively
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Published 15 Jun 2022

DDQ in mechanochemical C–N coupling reactions

  • Shyamal Kanti Bera,
  • Rosalin Bhanja and
  • Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

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  • obtained in 88% yield (Table 1, entry 1). However, in the presence of 1.2 equiv, the yield of 2a increased to 97% (Table 1, entry 2). Further, with the increase of the amount of DDQ to 1.5 equiv, no further improvement was obtained (Table 1, entry 3). In addition, we have screened several iodine oxidation
  • Information File 1, Table S1, entries 4 and 5). When molecular iodine or NIS were used as oxidants, product 5a was obtained in 83% and 80% yield, respectively (Supporting Information File 1, Table S1, entries 6 and 7). However, the yield of the desired product 5a slightly decreased to 92% with lowering of the
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Published 01 Jun 2022

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

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  • published an alternative and sustainable methodology, using phenyliodine(III) bis(trifluoroacetate) (PIFA) as an oxidizing agent of the demethylation reaction [86]. The hypervalent iodine(III) proved to be a good oxidizing agent in the formation of 10 (92% yield) (Table 3, entry 2). According to the authors
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Published 11 Apr 2022

Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor

  • Yuki Naito,
  • Naoki Shida and
  • Mahito Atobe

Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39

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  • other hand, the yield of 3a decreased even when the terminal halogen of the dihaloalkane was changed to iodine (Table 7, entry 3). LSV measurements showed that the reduction potential of 1,4-diiodobutane (2c) was almost the same as that of the substrate imine 1 (Supporting Information File 1, Figure S12
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Published 29 Mar 2022

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

  • Kian Donnelly and
  • Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

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  • Kian Donnelly Marcus Baumann School of Chemistry, University College Dublin, Science Centre South, Belfield, Dublin 4, Ireland 10.3762/bjoc.18.27 Abstract An efficient continuous flow process is reported for the synthesis of various 1,3,4-oxadiazoles via an iodine-mediated oxidative cyclisation
  • -oxadiazole unit [28][29][30][31][32][33]. In 2012, Guin and co-workers described the iodine-mediated cyclodesulphurisation of thiosemicarbazides, yielding the corresponding 1,3,4-oxadiazoles [32]. Subsequently, Yu and co-workers reported the iodine-mediated oxidative cyclisation of acyl hydrazones to form
  • oxadiazoles [33]. While this method provided the products in high yields, it required the use of super-stoichiometric quantities of iodine, which is potentially toxic and corrosive. This potential toxicity in combination with the requirement for the subsequent removal of excess iodine and potentially
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Published 25 Feb 2022

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

  • Rodolfo H. V. Nishimura,
  • Thiago dos Santos,
  • Valter E. Murie,
  • Luciana C. Furtado,
  • Leticia V. Costa-Lotufo and
  • Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

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  • of the anticancer agent verubulin. Thus, after regioselective 4-chloroquinazoline metalation by an in situ trapping metalation strategy, reaction quenching with iodine allowed us to isolate 4-chloro-8-iodoquinazoline in 83% yield. Surprisingly, further reaction of 4-chloro-8-iodoquinazoline with 4
  • . While anthranilamide (5) bromination with N-bromosuccinimide in acetonitrile at room temperature [29] furnished 2-amino-5-bromobenzamide (6a) in 78% yield, iodination of 5 with iodine in the presence of hydrogen peroxide in water [30] at 50 °C provided 2-amino-5-iodobenzamide (6b) in 89% yield. After
  • that, the cyclocondensation [29] of the halogenated anthranilamides 6a,b with benzaldehyde followed by dehydrogenation promoted by iodine gave the corresponding quinazolin-4(3H)-ones 7a,b, which we used in the next step without purification. Finally, chlorination [31] of quinazolin-4(3H)-ones 7a,b by
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Published 22 Dec 2021

Iron-catalyzed domino coupling reactions of π-systems

  • Austin Pounder and
  • William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

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Published 07 Dec 2021

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

  • Alla I. Vaskevych,
  • Nataliia O. Savinchuk,
  • Ruslan I. Vaskevych,
  • Eduard B. Rusanov,
  • Oleksandr O. Grygorenko and
  • Mykhailo V. Vovk

Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189

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  • includes the reaction of readily available anthranilic amides or hydrazides with pent-4-yn-1-ols or -carboxylic acids promoted by PdCl4 [15], Au(І) [16][17][18] or Cu(ІІ) [19] salts. In another version, the target compounds were obtained by iodine-catalyzed reaction of the aforementioned anthranilic acid
  • )-ones 7 upon action of bis(trifluoroacetoxy)iodobenzene (PIFA) (see Scheme 1D). A part from the well-known applications of hypervalent iodine compounds for oxidative rearrangements, fragmentations, halogenations and hydroxylations [37][38], they were also involved in the synthesis of N-heterocycles [39
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Published 25 Nov 2021

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

  • Umesh P. Aher,
  • Dhananjai Srivastava,
  • Girij P. Singh and
  • Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

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Published 04 Nov 2021

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

  • Ilya A. P. Jourjine,
  • Lukas Zeisel,
  • Jürgen Krauß and
  • Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

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  • . Benzylamines and derivatives thereof have been described in literature to be susceptible to oxidation by diverse reagents (tritylium ion [40], silver [38] and cerium salts [41], peroxides [42][43][44] and persulfates [45], nitroxyls [46], hypervalent iodine compounds [39][47], or tetrahalomethanes [48]) to
  • aldehyde (33%) being generated (Table 2, entry 11). Similar results were obtained when adding iodine to promote benzylic oxidation [56] (Table 2, entry 12). Finally, Pd(OAc)2 was added in hopes of improving the mediation of C–C bond formation [38] (Table 2, entry 13). Interestingly, here the yield of
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Published 02 Nov 2021
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