Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• , this new method creates two C–N bonds simultaneously based on a mono-halogenated starting material, thus allowing heterocycle formation with diminished halogen waste. Keywords: carbazoles; heteroaromatics; iodanes; metal-catalyzed; one-pot reaction; Introduction N-Acyl carbazoles are effective

• with a 47% yield. A method for the synthesis of similar annulated N-heterocycles from iodanes with nitriles is described by Chen et al. [34]. Next, we investigated O-bridged dibenzo[b,e][1,4]iodaoxin-5-ium salts as substrates, as was shown in a recent work [29]. Following the trend, we already observed

• equiv amide, 15 mol % CuI, 30 mol % diglyme, 3.00 equiv K2CO3 and 2.00 equiv dibenzo[b,d]iodol-5-ium trifluoromethanesulfonate. Scope of iodanes. aIsolated yields, 200 µmol scale, all reactions carried out in p-xylene, with 1.00 equiv amide 15 mol % CuI, 30 mol % diglyme, 3.00 equiv K2CO3 and 2.00 equiv

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

• 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

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

• Sandmeyer-type reaction (Scheme 7, reaction a) [49]. The reaction was efficient, although heteroaryl diazonium salts were reluctant in this reaction. To overcome these limitations, hypervalent iodinated species were used as substrates. The copper-mediated reaction with λ3-iodanes demonstrated a large

Thermal stability of N-heterocycle-stabilized iodanes – a systematic investigation

• Andreas Boelke,
• Yulia A. Vlasenko,
• Mekhman S. Yusubov,
• Boris J. Nachtsheim and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2019, 15, 2311–2318, doi:10.3762/bjoc.15.223

• Federation Department of Solid State Engineering, University of Chemistry and Technology, 16628 Prague, Czech Republic 10.3762/bjoc.15.223 Abstract The thermal stability of pseudocyclic and cyclic N-heterocycle-stabilized (hydroxy)aryl- and mesityl(aryl)-λ3-iodanes (NHIs) through thermogravimetric analysis

• stability with reactivity in a model oxygenation. Keywords: differential scanning calorimetry; hypervalent iodine; N-heterocycle; stability; thermogravimetry; Introduction Hypervalent iodine compounds, in particular aryl-λ3-iodanes, have found wide spread applications as oxidants and electrophilic group

• electrophilic hypervalent iodine atom in its ground state or directly influences its reactivity by stabilizing reactive intermediates or transition states. In recent years, a plethora of cyclic and pseudocyclic iodanes have been developed with covalently attached stabilizing ligands L2 and applied in a variety

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• hypervalent iodine(III)-catalyzed functionalization of alkenes and asymmetric reactions using a chiral iodoarene are summarized. Keywords: asymmetric catalysis; functionalization of alkenes; hypervalent iodine(III); Introduction Hypervalent iodine(III) reagents, also named as λ3-iodanes, have been widely

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• spirolactam derivatives 86 using chiral iodoarene 85 as precatalyst, mCPBA as an oxidant and TFE as an additive. The presence of 10.0 equivalents of H2O was required to get the reaction products in high yields with up to 92% ee (Scheme 30). The chiral hypervalent-λ3-iodanes were generated in situ by the

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• iodoarenes, which are released in stoichiometric amounts in any reaction mediated by λ3- or λ5-iodanes. In parallel to the development of solid-supported reagents or reactions catalytic in iodine, a third strategy has emerged to address this issue in terms of sustainability. The atom-economy of

• transformations involving stoichiometric amounts of λ3- or λ5-iodanes, thus, has been improved by designing tandem reactions that allows for incorporating the aryl motif into the products through a subsequent one-pot nucleophilic addition or catalytic coupling reaction. This review summarizes the main

• to this topic [1][2][3][4][5][6][7][8][9][10][11][12][13]. A still growing number of λ3- and λ5-iodanes are now available as non-toxic and environmentally benign reagents that allow for performing a wide range of transformations under mild conditions. The oxidation of functional groups, halogenations

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• Andreas Boelke Peter Finkbeiner Boris J. Nachtsheim Institute for Organic and Analytical Chemistry, University of Bremen, 28359 Bremen, Germany 10.3762/bjoc.14.108 Abstract Hypervalent iodine compounds, in particular aryl-λ3-iodanes, have been used extensively as electrophilic group-transfer

• -economical transformations using hypervalent iodine reagents (iodanes) as electrophilic group-transfer reagents. Iodanes, in particular iodonium salts, are well-balanced reagents in terms of stability, reactivity and synthetic and/or commercial availability and therefore it is not surprising to see these

• compounds as key reagents in a great number of recently developed transformations [3][4][5][6][7][8][9][10][11][12][13][14][15]. However, in terms of atom economy, they have an intrinsic problem: their high reactivity is based on the emergence of aryl iodides as supernucleofuges. λ3-Iodanes are the

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

• reagents. A number of iodanes with various oxidation states have been developed since the pioneering work of the German chemist Willgerodt, who synthesized PhICl2 [5]. Iodane reagents have been extensively used in applications such as oxidation, rearrangement, cross-coupling, functionalization

• ). 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

• )-iodanes were both acceptable substrates, but the process was inefficient with (VII)-iodane species. We surmise that IBX and DMP are rapidly reduced to a (III)-iodane in the presence of an alcohol, and that this species is most likely the reagent promoting the formation of compound 4a. Iodine and N

One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

• Natalia Soldatova,
• Pavel Postnikov,
• Olga Kukurina,
• Viktor V. Zhdankin,
• Akira Yoshimura,
• Thomas Wirth and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

• Diaryliodonium salts, which are also known as diaryl-λ3-iodanes, are widely considered to be an important and practically useful class of hypervalent iodine compounds [1][2][3][4]. Diaryliodonium salts have found broad synthetic application as electrophilic arylating reagents in reactions with various

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

• Morifumi Fujita,
• Koki Miura and
• Takashi Sugimura

Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53

• )-isomer. Keywords: 1,2-difunctionalization of alkenes; enantioselective synthesis; hypervalent iodine; oxidation; Findings Hypervalent aryl-λ3-iodanes have been widely used for metal-free oxidation with high selectivity in organic synthesis [1][2][3]. The reactivity of an aryl-λ3-iodane is controlled by

• reaction. A series of lactate-derived aryl-λ3-iodanes 4a–e was used for the oxidation of styrenes 1 in the presence of p-toluenesulfonic acid (TsOH) in dichloromethane. The reaction proceeded at −50 °C to give the 1,2-dioxytosylated product 3 and the rearranged product 5. The yields of 3 and 5 were

• planar structure of the benzylic cation. Thus, the tosylate ion may act as an effective nucleophile for the SN2 reaction of I1. The stereoface-differentiation in the dioxytosylation reaction using the lactate-derived aryl-λ3-iodanes is similar to that in preceding reactions [14], which include the