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

• intermediate 75. Subsequently, this intermediate is attacked by the palladium catalyst under a CO atmosphere to form the alkyl palladium species 76. Finally, the reductive elimination at the iodine(III) center and CO insertion into the newly formed C–Pd bond, affords the oxycarbonylation products 74 (Scheme 21

Synthesis of diamido-bridged bis-pillar[5]arenes and tris-pillar[5]arenes for construction of unique [1]rotaxanes and bis-[1]rotaxanes

• Ying Han,
• Li-Ming Xu,
• Cui-Yun Nie,
• Shuo Jiang,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2018, 14, 1660–1667, doi:10.3762/bjoc.14.142

• afforded diamido-bridged bis-pillar[5]arenes. 1H NMR and 2D NOESY spectra clearly indicated that [1]rotaxanes were formed by insertion of longer diaminoalkylene unit into the cavity of one pillar[5]arene with another pillar[5]arene acting as a stopper. The similar catalysed amidation reaction of pillar[5

Cobalt-catalyzed C–H cyanations: Insights into the reaction mechanism and the role of London dispersion

• Eric Detmar,
• Valentin Müller,
• Daniel Zell,
• Lutz Ackermann and
• Martin Breugst

Beilstein J. Org. Chem. 2018, 14, 1537–1545, doi:10.3762/bjoc.14.130

• , ligand coordination, insertion) shown in Scheme 2 which served as the starting point of this investigation [30]. We now report on our computational findings supported by novel kinetic investigations to establish the reaction mechanism of this synthetically useful C–H activation and to elucidate the role

• -electron intermediate 8a yielding 9a. Next, the insertion of the cyanating agent 2a into the cobalt–carbon bond takes place through TS3a. Within the four-membered transition state (Figure 2), the C–C bond to be formed is still rather long (C–C distance 1.92 Å), while the C–N distance is already

• the desired transformation. As the calculated rate-limiting transition state TS3 benefits from a stabilization of the developing negative charge on the sulfonamide, the relative rates of Scheme 3 provide further support for the migratory insertion representing the rate determining step [44]. As

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

• catalyzed cascade reaction to afford alkylidenefluorenes 49 (Scheme 17) [57]. In terms of mechanism, a Pd(0)/Cu(I)-catalyzed Sonogashira coupling reaction from the iodonium salt 48 delivers a 2-alkynyl-2’-iodoarene 50 that, then, cyclizes to 51 via insertion of the Pd(0) species into the iodoarene moiety

Oligonucleotide analogues with cationic backbone linkages

• Melissa Meng and
• Christian Ducho

Beilstein J. Org. Chem. 2018, 14, 1293–1308, doi:10.3762/bjoc.14.111

• , respectively, upon the insertion of base mismatches in the DNA counterstrand. Analyzing a 2:1 complex formed from two octameric thymidinyl DNG strands and one native DNA A8-mer, they concluded that base mismatches at either end of the DNA counterstrand sequence do not hamper hybridization as strongly as a

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

• the sulfonimidamide 31 in the presence of the chiral rhodium(II) catalyst A. Hereby, one equivalent of iodoarene 2 is released. The insertion of the nitrene species into the C(sp3)–H bond affords the amination product C, which is the final product of the first reaction step. In the following step, C

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• tropone unit: In 1975, Franck-Neumann and Martina reported the reaction of dimethyl diazomethane with tropone and benzotropones [83]. This reaction gave benzo-4,5-dimethyl-8,8-cyclooctatrienone (94, 30% isolable yield) as an insertion product via a carbonyl group and pyrazoline 95 as 1,3-dipolar addition

• unit: The ring-expansion product 188, which is a net insertion of a diazomethane unit into the tropone, was prepared from the reaction of 2,3-benzotropone (12) with dimethyl diazomethane (Figure 7) [83]. Benzohomoazocines 191–193 and benzomethoxyazocines 195–197 were prepared using a similar protocol

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• discovered and designed to competitively inhibit such interactions. Additionally, molecules that are capable of insertion between the DNA base pairs can also disfavor DNA–protein interactions directly or allosterically. Consequently, small molecule DNA binders have been in the limelight of drug-discovery

• are reports of natural and designed molecules that display multivalency in DNA recognition by binding at more than recognition sites (minor groove, major groove or base pair insertion) [11][12][13]. In synthetic multivalent ligands, which are made to enhance DNA affinity, tether length and composition

Correlation effects and many-body interactions in water clusters

• Andreas Heßelmann

Beilstein J. Org. Chem. 2018, 14, 979–991, doi:10.3762/bjoc.14.83

• to the three-body interaction energy Δ3(ABC). According to the three different possible pseudodimers, see Equation 12, one can extract the following three terms: Recall that using the supermolecule method the term Δ3(AB − C) is given by Δ3(AB − C) = E(ABC) − E(AB) − E(C). An insertion of the

Methyl isocyanide as a convertible functional group for the synthesis of spirocyclic oxindole γ-lactams via post-Ugi-4CR/transamidation/cyclization in a one-pot, three-step sequence

• Amarendar Reddy Maddirala and
• Peter R. Andreana

Beilstein J. Org. Chem. 2018, 14, 875–883, doi:10.3762/bjoc.14.74

• thought of as a synthetic equivalent to ‘CO’ for insertion into the 2-indolinone backbone (shown in Scheme 1). To further elaborate on this observation and for understanding the role of methyl isocyanide as a CIC, we designed an efficient synthetic strategy for spiro[indoline-3,2'-pyrrole]-2,5'(1'H

Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides

• Kartik Temburnikar and
• Katherine L. Seley-Radtke

Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65

• employed in the design of drugs, most notably in the fields of virology and cancer research [13][14][15]. Variations in the nucleoside scaffold are typically accomplished by the insertion, deletion or transposition of functional groups or atoms [23][24][25][26][27][28][29]. The varied properties of such

Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin–GnRH-III conjugates developed for targeted drug delivery

• Sabine Schuster,
• Beáta Biri-Kovács,
• Bálint Szeder,
• Viktor Farkas,
• László Buday,
• Zsuzsanna Szabó,
• Gábor Halmos and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 756–771, doi:10.3762/bjoc.14.64

• preclinical and clinical studies, was zoptarelin-doxorubicin also known as AEZS-108 (previously AN-152) [16]. The anthracycline doxorubicin was conjugated to the ε-amino group of GnRH-I-[6D-Lys] by insertion of a glutaric acid linker. The resulting ester bond can be cleaved by carboxylesterases, leading to

Volatiles from the xylarialean fungus Hypoxylon invadens

• Jeroen S. Dickschat,
• Tao Wang and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 734–746, doi:10.3762/bjoc.14.62

• derivative to the corresponding aldehyde 12 that upon O-methylation (green), likely with S-adenosylmethionine, would result in 17. The alternative oxidation of 12 by a Baeyer–Villiger monooxygenase could result in the insertion of an oxygen (blue) to yield the formate ester 21, followed by ester hydrolysis

Synthesis and biological evaluation of RGD and isoDGR peptidomimetic-α-amanitin conjugates for tumor-targeting

• Lizeth Bodero,
• Paula López Rivas,
• Barbara Korsak,
• Torsten Hechler,
• Andreas Pahl,
• Christoph Müller,
• Daniela Arosio,
• Luca Pignataro,
• Cesare Gennari and
• Umberto Piarulli

Beilstein J. Org. Chem. 2018, 14, 407–415, doi:10.3762/bjoc.14.29

• and co-workers conjugated α-amanitin to pHLIP (pH low insertion peptide) via linkers of different hydrophobicities [7]. The results indicated that pHLIP could deliver α-amanitin into cells and induce cell death in 48 h by a pH-mediated direct translocation across the membrane and cleavage of the

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• -hydroxyalkanoates from the reaction of α-halocarbonyl compounds with aldehydes or ketones in the presence of zinc [1]. Today, the Reformatsky reactions are more generally defined as metal insertion into carbon–halogen bonds which are activated by carbonyl groups or related functions at vicinal or vinylogous

Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)

• Michał Nowacki and
• Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14

• ]. Several methods use prerequisite quinoline derivatives for the construction of the pyrrole ring of quindoline. 2-(2-Aminophenyl)-3-bromoquinoline cyclized to quindoline by reacting with pyridinium hydrochloride (d) [14]. Insertion of nitrene generated from 2-(2-nitrophenyl)quinoline by triethylphosphite

Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial

• Tamara Šmidlehner,
• Ivo Piantanida and
• Gennaro Pescitelli

Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5

• chirality due to the structural changes caused by binding; b) an induced (I)CD as a result of ligand insertion into chiral binding sites; c) exciton coupling between multiple aggregated ligand molecules. The appearance of one or more isodichroic points (the CD equivalent of isosbestic points) during ECD

• indicated by the blue double-arrow in Figure 7) is most probably oriented at about 45° to the DNA chiral axis, thus matching the minor groove of the DNA [6][10]. For a planar molecule, this implies non-intercalative binding, whereas, for many potentially nonplanar or flexible molecules, a partial insertion

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

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

Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres

• Myriam Drouin and
• Jean-François Paquin

Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262

• -fluoro-2-phosphonoacetate (1) was converted into the α-fluoro-α,β-unsaturated carbonyl 3 using the HWE olefination. The (Z)-isomer was obtained with complete selectivity. Then, reduction of the ester into the corresponding alcohol followed by a Mitsunobu reaction allowed the insertion of the NH

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• produce thiophenes 4 through an ordinary N–H insertion process [6][7][8][9][10][11][12][13] (Scheme 5). To the best of our knowledge, the discovered processes are the first examples of intramolecular reactions of thiocarbonyl ylides with cyano groups, acting as an electrophile, with subsequent 1,3

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• approximately 50 °C higher melting point (e.g., 1a/1b with Tm = 261/215 °C). Thus, the insertion of an acetylene linker decreases the melting point and causes thermal instability in the liquid phase. Derivatives 1a/2a containing a 1,4-phenylene linker showed the highest Tm and Td values of 261/244 and 330/345

• be the strongest electron donor within the studied series of compounds. This is in accordance with our previous observations [9][35]. Except for chromophores 3a,b, insertion of an additional acetylene linker rather extended the electrochemical HOMO–LUMO gap (series a vs b). Linear optical properties

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• converts into the orthoester 10 via insertion into the C–O bond. The reaction mechanism for the formation of 8 and 9 comprises the initial attack of the nucleophilic carbene onto the electron-deficient C atom of E-1b to give an intermediate zwitterion 11. The latter undergoes two competitive reactions. The

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• identified as metal organic framework (MOF) or coordination polymers that are synthesized by reaction with a metallic salts (e.g., copper [65], lanthanides [66]) under hydrothermal conditions [67][68] or by insertion of phosphonic acid in low dimensional inorganic materials like layered double hydroxide (LDH

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

• Valentin A. Rassadin,
• Mirko Scholz,
• Anastasiia A. Klochkova,
• Armin de Meijere and
• Victor V. Sokolov

Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187

• latter transformation was a rhodium octanoate-catalyzed intramolecular carbenoid insertion into an ortho CAr–H bond (Scheme 1) [21][22], which proceeded with good yields in most cases. However, with non-equivalent aryl ortho-positions in the starting diazo compounds, mixtures of regioisomers – virtually