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

• will be discussed as a method for the formation of multiple bonds in a single step. Mechanistically, Fe-catalyzed oxidative addition and functionalization reactions proceed similarly to cross dehydrogenative couplings (vide supra); however, these reactions will result in byproducts other than the

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• , this synthetic method (nucleophilic aromatic substitution reaction) is crucial for the development of alternative C–N bond-forming reactions to conventional metal-involved cross-couplings, providing axially chiral N-arylcarbazoles 60 in good yields with remarkable enantiocontrol through a

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• nucleophile and the alkyl or aryl radicals. From 2013 to 2019, the authors disclosed a series of nitrogen, sulfur, oxygen, and carbon nucleophiles for photoinduced, copper-catalyzed cross-couplings with organic halides. The copper–nucleophile complexes that were generated in situ as photoredox catalysts

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• challenging operation in organic synthesis. While significant advances had been accomplished with (hetero)aromatic C(sp2)–H alkylations [79][80][81], examples for C(sp3)–C(sp3) couplings through C–H activation are scarce [82][83][84]. In this context, a synergistic combination of photoredox catalysis and

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• ). Correlations for H5/H7, H5/H9, and H7/H9 and large scalar couplings (3JHH > 10 Hz) for H5/H6ax, H6ax/H7, and H5/H9 established the trans-ring fusion of the dehydrodecalin moiety. The axial orientation of the methyl group at C8 was evidenced by NOESY correlations H26/H6ax and H26/H10. Correlations of H25/H10

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• evidence for radical pathways involving vanadium-peroxo species [76], with a few exceptions [95]. Vanadium-based catalysts have been employed in carbon–carbon bond formation reactions, such as arene couplings, thereby proving especially useful in the synthesis of bioactive compounds, including natural

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• isotopically-labeled hydrazides could also be employed. Notably, this methodology considerably shortened the existing synthetic routes for adding a methyl group to olefins. More recently, the Bradshaw group has been exploring the potential use of tosyl hydrazones in reductive couplings with olefins initiated

• C, which undergoes an oxidation process to generate carbocation D. A proton abstraction from D then affords the observed product. Cross-coupling reaction between unactivated olefins and alkyl halides under nickel catalysis The use of alkyl halides in transition-metal-catalyzed cross-couplings to

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

• Emine Salamci and
• Yunus Zozik

Beilstein J. Org. Chem. 2021, 17, 705–710, doi:10.3762/bjoc.17.59

• multiplet part at 5.24–5.15 ppm, some splittings disappeared. This experiment clearly shows that the proton H-3 has couplings to both acetoxy protons H-2 and H-4. Furthermore, the proton H-3 resonates as a doublet of doublets with coupling constants of J = 8.8 and 2.7 Hz, clearly indicating that H-3 and H-2

Unexpected rearrangements and a novel synthesis of 1,1-dichloro-1-alkenones from 1,1,1-trifluoroalkanones with aluminium trichloride

• Beatrice Lansbergen,
• Catherine S. Meister and
• Michael C. McLeod

Beilstein J. Org. Chem. 2021, 17, 404–409, doi:10.3762/bjoc.17.36

• trichloride; dichloroalkenes; Friedel–Crafts alkylation; rearrangement; trifluoroalkanes; Introduction 1,1-Dichloro-1-alkenes are valuable synthetic intermediates and have been employed in Pd-mediated cross couplings of one or both chlorine atoms [1][2][3][4][5][6][7], carbonylation reactions [8], and C–H

Selective synthesis of α-organylthio esters and α-organylthio ketones from β-keto esters and sodium S-organyl sulfurothioates under basic conditions

• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Thiago Barcellos,
• Claudio C. Silveira and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2021, 17, 234–244, doi:10.3762/bjoc.17.24

• -rich N-heterocycles [2][3][4], decarboxylative cross-coupling reactions with propiolic acid derivatives [5], Michael addition reaction [6], cross-couplings catalyzed by Pd [7] and Cu salts [8][9], the preparation of symmetrical and nonsymmetrical disulfides [10][11], and the synthesis of β-acetamido

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• couplings and NOE effects shown. Our previous efforts in the field of functionalization of sugar-derived lactams. Preliminary experiment in search of a procedure for the synthesis of 2-(1H-tetrazol-5-yl)-iminosugars. Synthesis of a new class of alkaloid scaffold using the presented methodology. Synthesis of a

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• sp. and displaying inhibitory activities towards telomerases. The classical synthetic approach for carbohelicenes is the oxidative photocyclization of stilbene derivatives [1][2][3][4][5][6][7][8][9][10][11]. The latter are generally available via the Wittig, Heck-type or McMurry couplings. It is

Isolation and structure determination of a tetrameric sulfonyl dilithio methandiide in solution based on crystal structure analysis and ⁶Li/¹³C NMR spectroscopic data

• Jürgen Vollhardt,
• Hans Jörg Lindner and
• Hans-Joachim Gais

Beilstein J. Org. Chem. 2020, 16, 2057–2063, doi:10.3762/bjoc.16.172

• couplings shows, however, that the carbon lithium bonds in 2a-I have a covalent contribution as generally observed for organolithiums [55]. Three mechanisms most likely contribute to the stabilization of the negative charge of the carbon atoms of tetramer (2a)4·(THF)6 and hexamer (2a)6·Li2O·(THF)6

• Symmetric carbon–lithium chain of 2a-I in THF, showing the carbon–lithium connectivities, multiplicities of the NMR signals (left), and magnitudes of 1J(6Li,13C) couplings in Hz (right) [15]. the structure of (2a)6·Li2O·(THF)6 in the crystal [15]. Color code: black, C; green, Si; yellow, S; red, O; pink, Li

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• -metathesis reaction was employed in numerous syntheses, the drawbacks of this strategy include the high catalyst loading and the excess of the olefin coupling partners. To date, the most efficient strategy for the union of the fragments relies on Pd-catalyzed sp2–sp2 couplings. Structures of spliceostatins

Polarity effects in 4-fluoro- and 4-(trifluoromethyl)prolines

• Vladimir Kubyshkin

Beilstein J. Org. Chem. 2020, 16, 1837–1852, doi:10.3762/bjoc.16.151

• the conformation adopted by the ring. A C4-endo conformation exhibits two vicinal J couplings with one value being large and one being small, whereas a C4-exo conformation displays two large J couplings [66] (Figure 4). A substituent at the C4-atom creates a certain preference towards one or another

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• last decade particular attention has been focused on two modern fields, C–H bond activation, and visible-light-induced photocatalysis. Couplings through C–H bond activation involve the use of non-prefunctionalized substrates that are directly converted into more complex molecules, without the need of a

• photoredox catalysis. This interception leads to a new metallic key intermediate 3 by single-electron transfer (SET). The desired coupling product 4 is then obtained after a reductive elimination (Figure 19). Applying such an approach paved the way towards unprecedented couplings benefiting from a SET

• combination of photocatalysis and metal-catalyzed C–H activations upholds the desired couplings under, usually, mild conditions and at room temperature, while utilization of non-prefunctionalized coupling partners reduces the waste formation. Last but not least, the use of visible light, one of the most

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• combined with a solution-phase reagent, including: (1) copper(I) oxide to produce N-heterocyclic carbene–Cu(I) complexes for use as catalysts [13]; (2) proline to perform proline-based catalytic reactions [14]; (3) zinc powder to produce organozinc halides in tandem with Negishi couplings [15]; (4) zinc

Distinctive reactivity of N-benzylidene-[1,1'-biphenyl]-2-amines under photoredox conditions

• Shrikant D. Tambe,
• Kwan Hong Min,
• Naeem Iqbal and
• Eun Jin Cho

Beilstein J. Org. Chem. 2020, 16, 1335–1342, doi:10.3762/bjoc.16.114

• brine. The organic layer was dried over anhydrous MgSO4 and concentrated in vacuo. The desired vicinal diamine product was purified by silica-gel column chromatography using hexane/EtOAc as the eluent. Photocatalytic transformations of imines. Substrate scope for the radical cross-couplings. Reaction

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• , the ability of transition metal complexes to intercept alkyl radicals has been exploited for expanding the possibility of C–C bond formation reactions to cross-couplings. In all of these transformations, the substituents on the alkyl radical determine if it reacts as a nucleophile or an electrophile

• radicals are electrophilic, with the substitution playing an important role [133][134][135]. As they are prone to efficient HAT, C(sp3)–H couplings at remote positions have been intensively studied [128][130][132][136]. Aminyl and aminium radicals display the opposite philicity: aminyls are nucleophilic

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• . Protons H-8 and H-9 showed three-bond couplings (J = 8.2 Hz), while H-9 showed a weak four-bond correlation with H-5 (J = 1.9 Hz). Relatively intense cross peaks from H-5 and H-9 to the deshielded carbon C-7 (δC 152.8) suggested the oxygen functionality at the meta-position to C-5 and C-9. Intense HMBC

Suzuki–Miyaura cross coupling is not an informative reaction to demonstrate the performance of new solvents

• James Sherwood

Beilstein J. Org. Chem. 2020, 16, 1001–1005, doi:10.3762/bjoc.16.89

• objective of this work was to reveal if there is a relationship between the productivity of Suzuki–Miyaura cross couplings and the properties of the solvent, and whether this could be used to justify solvent selection. The choice of solvent is one variable that dictates reaction rate, selectivity

• applicable) of Suzuki–Miyaura cross couplings [8]. Despite this, the reaction is generally tolerant of a wide range of solvents (often an ether or amide solvent is used, and water is a common co-solvent). This calls into question the benefits of using Suzuki–Miyaura cross coupling as a test of new solvents

• enough to definitively establish a measurement of solvent performance in Suzuki–Miyaura cross couplings, a short optimisation study was conducted to improve the conversion to 4-phenylacetophenone in 2-MeTHF (originally 16%). Reducing the water content to an 18:1 v/v ratio and increasing the excess of