Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• retardants [14]. Sulfoxides are prominent pharmaceutical ingredients, while phosphine oxides improve solubility of corresponding compounds [15] and have applications in catalysis and materials science [16]. Selenoxides find use as oxygen transfer agents and donor ligands in metal catalysis and organic

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

• confirm the failure of only the M06-2X NMR method for compounds with multiple P–C bond character. We finish with two challenging examples, one a relatively recent report by the Radosevich group of a novel catalytic oxygen transfer reaction involving four-membered ring phosphorus compounds [83], and one

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• (at 100 °C) are main drawbacks of this methodology. DMF has been the solvent of choice in most cobalt-based epoxidation systems and it has been proposed that this solvent could serve as oxygen-transfer agent but, at the same time, could lead to considerable amounts of formamide byproducts [39][40]. On

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

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

• Katarzyna Włodarczyk,
• Piotr Borowski and
• Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

• ketophosphonates from vinylphosphates [53]. [1,4]-Rearrangements include that of o-phosphorus-substituted benzyl carbanions [34], phosphorus group migration in O-phosphorylated 1,4-benzodiazepines [54], or phosphoryl group carbon-to-oxygen transfer [55]. The common feature of every rearrangement presented above is

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

• ). We demonstrated that the N-heterocycle significantly influences the important I–L1 bond length and subsequently has a profound impact on the reactivity of the iodane in oxygen transfer reactions [29][30]. Since the combination of a highly oxidized hypervalent iodine species with N-heterocycles with a

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• iodobiarenes to synthesize a new class of I(III) and I(V) reagents 17. These were applied for the hydroxylative dearomatization of phenolic derivatives 42 followed by the successive use of the hydroxylated products as dienes in [4 + 2] cycloaddition reactions [42]. This new reagent promoted oxygen transfer in

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

• Morten M. C. H. van Schie,
• Tiago Pedroso de Almeida,
• Gabriele Laudadio,
• Florian Tieves,
• Elena Fernández-Fueyo,
• Timothy Noël,
• Isabel W. C. E. Arends and
• Frank Hollmann

Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58

• biocatalytic processes have been reported in flow reactors [19], mostly advocating easier process intensification in combination with enzyme immobilization [20][21][22][23]. Also the higher oxygen-transfer rates in flow reactions compared to batch reactions have been emphasised by several groups. Here, reactor

• 13.5 s−1. Even more interestingly, at higher flow rates apparent TF of up to 38 s−1 (RT = 5 min) were observed. This value exceeds the previously determined kcat(PeAAOx) (Figure 1) significantly. We attribute this observation to an increased oxygen-transfer rate at high flow rates. In the case of the 5

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• oxygen-transfer (Scheme 8, lower part) [117]. Besides making use of oxygen or air together with a stoichiometric activator/reductant as described above (Scheme 7 and Scheme 8), the photooxygenation of prochiral substrates like β-ketoesters 1 with O2 or air in the presence of a chiral PTC and TPP

• of course the most economical way of carrying out oxidations. However, there have also been several rather successful and highly enantioselective reports that describe analogous α-hydroxylation reactions by using alternative oxygen-transfer reagents (Scheme 10). A few years ago, Meng et al. carried

• (III)-based reductant. Asymmetric ammonium salt-catalysed α-photooxygenations. Asymmetric ammonium salt-catalysed α-hydroxylations using organic oxygen-transfer reagents. Asymmetric triazolium salt-catalysed α-hydroxylation with in situ generated peroxy imidic acid 24. Phase-transfer-catalysed

The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• ). These compounds can only form mono-esters with the metal oxidant (Scheme 3). Therefore, they exhibit a different reactivity and a less ordered transition geometry in the oxygen transfer reaction and are thus categorized as a distinct class of oxidative cyclization, referred to as type C reaction. In

Copper-mediated synthesis of N-alkenyl-α,β-unsaturated nitrones and their conversion to tri- and tetrasubstituted pyridines

• Dimitra Kontokosta,
• Daniel S. Mueller,
• Dong-Liang Mo,
• Wiktoria H. Pace,
• Rachel A. Simpson and
• Laura L. Anderson

Beilstein J. Org. Chem. 2015, 11, 2097–2104, doi:10.3762/bjoc.11.226

• -unsaturated nitrones, which undergo a subsequent thermal rearrangement to the corresponding tri- and tetrasubstituted pyridines. The optimization and scope of these transformations is discussed. Initial mechanistic experiments suggest a reaction pathway involving oxygen transfer followed by cyclization

• . Keywords: Chan–Lam; copper; nitrone; oxygen transfer; pyridine; Introduction While most applications of the Chan–Lam reaction are focused on the synthesis of aryl ethers and aryl amines, our group has been interested in the use of the Chan–Lam reaction for the synthesis of O-alkenyl oximes and

• , enaminoketone 16ae, and pyridine 9ae was observed [54][55]. Further heating this mixture of intermediates for 4 h resulted in the sole formation of pyridine 9ae. This experiment suggests that the conversion of nitrone 8ae to pyridine 9ae proceeds by oxygen transfer to give 16ae and nucleophilic addition of the

Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants^§

• Rudolf Knorr,
• Thomas Menke,
• Johannes Freudenreich and
• Claudio Pires

Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28

• the solvent at ≥100 °C through an initial chlorine particle transfer to give a Cl,K-carbenoid. This short-lived intermediate disclosed its occurrence through a reversible proton transfer which competed with an oxygen transfer from DMSO that created dimethyl sulfide. The presumably resultant transitory

• possible SNV reaction of 12 with DMSO and/or dimsyl-K (11), as proposed in Scheme 3 and later on as follows. In a rapid oxygen-transfer reaction that is known [31][32] for saturated carbenes or carbenoids, 12 will attack the solvent DMSO to generate the K,O-carbenoid 15 which decays in an E1cb-like

• intermediate 19 would isomerize to 22 and then dissociate into KCHCl2 (21) and product 23. As a Cl,K-carbenoid, 21 will fall a victim to the above-mentioned type of oxygen-transfer reaction [31][32] with DMSO, via 25 for example, to furnish Me2S and potassium formate (26) which was actually detected (δH = 8.54

Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc) oligomers and N,N-diacetyllactosamine (LacDiNAc) based on galactose oxidase treatment

• Christiane E. Kupper,
• Ruben R. Rosencrantz,
• Birgit Henßen,
• Helena Pelantová,
• Stephan Thönes,
• Anna Drozdová,
• Vladimir Křen and
• Lothar Elling

Beilstein J. Org. Chem. 2012, 8, 712–725, doi:10.3762/bjoc.8.80

• improve the reaction in such a way as to overcome the inhibitory effects [42][52][53]. The surface-to-volume-ratio was kept high to ensure sufficient oxygen transfer through the solvent surface. Accordingly, (semi-)preparative reactions were performed in open glass vessels to increase the transfer rate in

• . Enzyme activity was determined from the linear reaction rate. Oxidation of 1a–d and 2 Standard oxidation reactions were performed in oxygen-saturated sodium phosphate buffer (50 mM, pH 6, saturated by flushing pure oxygen into the buffer for 10 min). Open glass vessels were used to allow easy oxygen

• transfer, and the reaction mixtures were incubated at 30 °C under gentle mixing at 60 rpm for 5.5 h. For the oxidation of 10 µmol t-Boc-saccharide (1a–d, 2), 15.5 U galactose oxidase and 322 U peroxidase were used. Samples were taken to control the progress of the synthesis and the reactions were stopped

Construction of cyclic enones via gold-catalyzed oxygen transfer reactions

• Leping Liu,
• Bo Xu and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2011, 7, 606–614, doi:10.3762/bjoc.7.71

• - or Lewis acid-catalyzed oxygen transfer from carbonyl to carbon–carbon triple bond, the so-called alkyne–carbonyl metathesis, has attracted much attention because this atom economical transformation generates α,β-unsaturated carbonyl derivatives which are of great interest in synthetic organic

• chemistry. This mini-review focuses on the most recent achievements on gold-catalyzed oxygen transfer reactions of tethered alkynones, diynes or alkynyl epoxides to cyclic enones. The corresponding mechanisms for the transformations are also discussed. Keywords: alkyne–carbonyl metathesis; cyclic enones

• ; gold-catalyzed; oxonium; oxygen transfer; Review α,β-Unsaturated carbonyl derivatives are not only important building blocks in synthetic organic chemistry, but are also a significant motif in natural products and biologically active compounds [1][2][3][4][5][6][7][8]. The construction of the