Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• tetrachlorophthalimide (TCPhth) active esters towards C(sp3)–N cross-couplings with nitrogen heterocycles (Scheme 27). The catalytic reaction was proposed to begin by oxidative addition of RAE 104 to catalyst Bi-1, forming an in cage radical pair consisting of BiII species 130 and α-amino radical 107 (Scheme 27B

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• novel metallaphotoredox catalysis by combining the NaI/PPh3 photoredox catalyst with a Cu(I) catalyst to accomplish diverse C–O/N cross-couplings of alkyl N-hydroxyphthalimide esters 3 with various phenols/secondary amines 30 (Scheme 13) [24]. It was anticipated the utilization of computational methods

• bioisostere for a range of functional groups (such as CH2OH, CH2OCH3, CH2NH2, and CH2SH). Among the various methods available, radical-involving cross-couplings have proven to be the most effective [48][49]. However, the generation of the CH2F radical remains to be a challenging task. Therefore, there is an

• alkylation employing ammonium iodide. NaI/PPh3/CuBr cooperative catalysis for photocatalytic C(sp3)–O/N cross-coupling reactions. Proposed mechanism of NaI/PPh3/CuBr cooperative catalysis for photocatalytic C(sp3)–O/N cross-couplings. Photocatalytic decarboxylative [3 + 2]/[4 + 2] annulation between enynals

C–H bond functionalization: recent discoveries and future directions

• Indranil Chatterjee

Beilstein J. Org. Chem. 2023, 19, 1568–1569, doi:10.3762/bjoc.19.114

• well as famous Noble-prize-winning cross-couplings, therefore approaching another step up towards sustainability. Likewise, a free-radical process is also a classical way to functionalize nonactivated C−H bonds in which site selectivity arises either from the relative strength of the C−H bonds or from

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• synthesis has increased dramatically and has rapidly become a routine tool for classical synthesis [26][27][28][29]. In particular, many efforts have been devoted to the development of flow alternatives for transition-metal-catalyzed cross-couplings [30] and for some C–H functionalizations [31

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• insect sex pheromones as an alternative to conventional pesticides is in constant growth. In this report, we discuss the recent contributions brought by our groups in the field of iron-catalyzed cross-couplings applied to the synthesis of insect pheromones. The pivotal question of the development of

• cross coupling reaction developed by Kochi, leading to better yields, with no need to use an excess of one of the coupling partners (Scheme 2b) [12]. The yields obtained using this ligand-free method are comparable to those obtained in recent palladium-mediated alkyl–vinyl cross-couplings using

• reactions, which witnessed considerable development in the last two decades [14], several cross-coupling methodologies involving soft nucleophiles, such as iron-mediated Suzuki–Miyaura cross-couplings, being reported [15]. The introduction of alkyl–alkenyl linkage by means of iron-catalyzed cross-coupling

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• -formation processes (Scheme 12) [82][83]. These recently obtained results indicate that a sulfur-stabilized carbon radical derived from 1,4-dithiane (1) is a viable reaction intermediate, opening up the use of 1,4-dithianes in various free radical-type cross-couplings. 5 Synthetic equivalents of the allyl

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• Berlin, Germany 10.3762/bjoc.18.115 Abstract Metallaphotoredox catalysis is a powerful and versatile synthetic platform that enables cross-couplings under mild conditions without the need for noble metals. Its growing adoption in drug discovery has translated into an increased interest in sustainable

• catalytic approaches [9]. Especially the combination with other transition metal catalysts (metallaphotoredox catalysis), such as nickel complexes, resulted in a vast number of new methods to achieve cross-couplings under mild conditions [10]. However, the conditions of these methods are often hard to

• light-mediated carbon–heteroatom cross-couplings of sodium sulfinates, carboxylic acids and sulphonamides with aryl halides (Figure 2) [28]. Although recyclable, batch reactions are characterized by long reaction times (24 h). Here, we present a detailed investigation of a continuous-flow strategy for

Earth-abundant 3d transition metals on the rise in catalysis

• Nikolaos Kaplaneris and
• Lutz Ackermann

Beilstein J. Org. Chem. 2022, 18, 86–88, doi:10.3762/bjoc.18.8

• alternatives. Furthermore, metal-catalyzed cross-couplings do require prefunctionalizations on both substrates and generate stoichiometric quantities of undesired chemical waste, thus reducing the sustainability of these catalytic transformations. To address these major limitations, the past decades have

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

• Hendrik Gruß,
• Rebecca C. Feiner,
• Ridhiwan Mseya,
• David C. Schröder,
• Michał Jewgiński,
• Kristian M. Müller,
• Rafał Latajka,
• Antoine Marion and
• Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

• -switchable azobenzene staple [33][34]. Moreover, it has been shown that Pd-mediated cross-couplings can be successfully employed in the generation of cyclic and conformationally stabilised peptides. The groups of Buchwald, Pentelute, and Ackermann pioneered the development of Pd-mediated arylation chemistry

• ][54][55]. It has been proven that Pd-catalysed cross-couplings are very versatile tools for selective and bioorthogonal modifications of haloindoles, halotryptophans and halotryptophan-containing peptides as well as natural products [56][57][58][59][60][61][62][63][64][65][66][67][68][69][70

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

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

• 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

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

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

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

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

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

Accelerating fragment-based library generation by coupling high-performance photoreactors with benchtop analysis

• Quentin Lefebvre,
• Christophe Salomé and
• Thomas C. Fessard

Beilstein J. Org. Chem. 2020, 16, 982–988, doi:10.3762/bjoc.16.87

• findings on C–N cross-coupling conditions. In these works, nickel-photoredox-catalyzed cross-couplings were the most successful with success rates up to 50% [10]. This was an improvement from non-photocatalyzed conditions, where success rates of 11–33% were observed for palladium-catalyzed cross-coupling

• electrochemically-mediated nickel-catalyzed cross-couplings. Electron-deficient aniline products are less prone to oxidative decomposition. BCP-amines were viable coupling partners but gave the corresponding products 1a–e in poor purities. Simple azetidines partook the reaction to give 2a–c while azaspiro[3,3

Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts

• David Schönbauer,
• Carlo Sambiagio,
• Timothy Noël and
• Michael Schnürch

Beilstein J. Org. Chem. 2020, 16, 809–817, doi:10.3762/bjoc.16.74

• , electrophilic alkyl radicals were used in several transformations, such as electrophilic cross couplings under nickel catalysis, either with boronic acids [35] or different (aryl)halides [36][37][38]. Furthermore, visible light-promoted uncatalyzed electron transfer via the formation of electron donor–acceptor

Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules

• Valerian Dragutan,
• Ileana Dragutan,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68

• efficiently produce key 1,3-dienic frameworks, further subjected to sequential functionalization. The main focus was placed on strategies combining enyne metathesis with traditional chemical transformations such as Diels–Alder cycloaddition, Suzuki–Miyaura or Heck cross-couplings, aromatization, epoxidation

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• , Ohmiya and co-workers envisioned inverting the polarity of an aldehyde 81 via conversion into the corresponding α-alkoxyalkyl Cu(I) anion 78. Utilizing 78, which undergoes transmetallation to an initially formed Pd(II) intermediate (from oxidative addition) led to cross couplings affording benzhydryl

Formal preparation of regioregular and alternating thiophene–thiophene copolymers bearing different substituents

• Atsunori Mori,
• Keisuke Fujita,
• Chihiro Kubota,
• Toyoko Suzuki,
• Kentaro Okano,
• Takuya Matsumoto,
• Takashi Nishino and
• Masaki Horie

Beilstein J. Org. Chem. 2020, 16, 317–324, doi:10.3762/bjoc.16.31

• described previously [25]. We chose five chlorobithiophenes as monomer precursors for the alternating copolymers, as summarized in Scheme 3. The cross-couplings, as shown in Scheme 2, proceeded smoothly to afford the bithiophenes 4 in 46–92% yield. The synthesis of the alternating copolymers was carried out

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• temperature, it is also carried out in benign acetone as solvent and does not require any additional oxidant. It circumvents the additional prefunctionalization of the BQ step usually required for Pd cross-couplings [15], while also showing greater functional group tolerance than radical-based methods [16][17

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• application in STED (stimulated emission depletion) microscopy, as sensor molecules for, e.g., ions and as fluorophores for the optical imaging of tumors. Different strategies were already employed for their synthesis. Because of just three known literature examples in which Suzuki–Miyaura cross couplings