Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• using metal complexes as switching units (Figure 20). This concept named “weak link approach” (WLA) [78] uses square planar d8-transition metal complexes with two hemilabile bidentate ligands composed of a strong binding site (phosphorus) and a weaker one (generally sulfur, oxygen, selenium, or nitrogen

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• ]. Concerning the 13C chemical shift for the aliphatic carbons directly attached to the phosphorus atom a slight down-field shift is found for 2a–i (24–20 ppm, 1JPC ≈ 64 Hz) when compared to similar alkyltriphenylphosphonium bromides (20–18 ppm, 1JPC ≈ 54 Hz) [37]. Finally, the 31P NMR shift (against H3PO4, 85

• phosphonium phenolates are largely unaffected by changing a phenyl group for an alkyl group like in 2a–i. Also other similarly substituted phosphonium salt species give the phosphorus signal in the range of 26–19 ppm [28][37][38]. For comparison, the phosphine 1 exhibits a 31P NMR shift of −29.7 ppm [35]. In

• phosphorus signal for 2d). Stability tests were also performed in two different deuterated solvents, CDCl3 and DMSO-d6. No air or moisture exclusion was applied. The tests were performed at room temperature and at 60 °C. 1H and 31P NMR spectra of the solutions were taken after 24, 48 and 72 h. At room

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• sections also include some examples of non-phosphorus glycosylated antitumor ether lipids (GAEL) but more details on the biology of these ether lipids can be found elsewhere [49][50][51]. The synthesis of analogues of archaeal ether lipids is not included herein but the reader can refer to other articles

• which the acyl group can shift easily from the sn-2 to the sn-3 position. Noteworthy, the preparation of 8.2 was achieved in 3 steps from phosphorus trichloride and by using choline tetraphenylborate (prepared from choline chloride) [87] instead of the choline p-toluenesulfonate salt to improve the

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• the presence of NaOAc under an AcOH/H2O mixture at 75 °C in 2.5 h (Scheme 4). Further, these synthesized N-α-substituted compounds were subjected to electropolymerization studies. In another method described for the synthesis of N-substituted pyrroles 11, Fang et al. [58] used phosphorus pentoxide

• P2O5 under toluene at 110 °C. Since phosphorus pentoxide gives phosphoric acid esters upon reaction with alcohols and also has less acidic character, the authors hypothesized that it might be a good choice for the conversion of amines 10 into their corresponding pyrroles. The results were according to

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• /bjoc.19.50 Abstract Phostams, phostones, and phostines are a series of 1,2-azaphosphaheterocycle and 1,2-oxaphosphaheterocycle 2-oxide derivatives. They are phosphorus analogues of lactams and lactones and important biologically active compounds. The strategies for the synthesis of medium and large

• phosphorus-containing heterocyclic compounds [1][2] and significant agrochemicals [3], medicinal agents [4], and organic materials [5]. They are also organic synthetic intermediates and building blocks [6][7]. To date, only limited four-membered β-phostams [8][9], β-phostones and β-phostines [10] have been

• '-carboxylates 83 in 5–10% yield as byproducts. The major products 84 were generated via Michael addition and the nucleophilic addition–elimination of the carbanion of the generated enolate moiety, while the oxyanion of the enolate moiety attacked the phosphorus to form the byproducts 83 (Scheme 18) [40][41

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• final product 195a. In 2019, the Shao group reported the Rh/Zn-catalyzed domino ARO/cyclization of oxabenzonorbornadienes 30 with phosphorus ylides 201 (Scheme 35) [83]. Despite the difficulty of using phosphorus ylides as nucleophiles in metal-catalyzed reactions due to their ability to strongly bind

• transition metals, this reaction proceeded smoothly with a broad range of ester-, ketone-, and amide-stabilized phosphorus ylides. Oxabenzonorbornadienes bearing both EWG and EDG substituents worked well including bridgehead-substituted substrates which only experienced a slight reduction in yield. Similar

• to other ARO reactions, the catalytic cycle is proposed to begin with the oxidative insertion of the Rh(I) catalyst into the bridgehead C–O bond producing 204. The phosphorus ylide attacks 204 in an SN2’ fashion on the endo face giving the ring-opened 205 as well as regenerating the Rh(I) catalyst

Dipeptide analogues of fluorinated aminophosphonic acid sodium salts as moderate competitive inhibitors of cathepsin C

• Karolina Wątroba,
• Małgorzata Pawełczak and
• Marcin Kaźmierczak

Beilstein J. Org. Chem. 2023, 19, 434–439, doi:10.3762/bjoc.19.33

• as potential inhibitors of cathepsins. The phosphorus atom by default should mimic the tetrahedral intermediate, but this role may also be played by the hydroxy group present in hydroxyphosphonates, which mimic the carbonyl carbon in the peptide bond by forming a hydrogen bond with the amino group of

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• (Table 1, entry 11). These results indicate that the accessibility of the phosphorus center is important. Next, the solvent was investigated. Replacing acetonitrile with dimethyl sulfoxide (DMSO), or dimethylacetamide (DMA), or acetone, or ethyl acetate (EA), resulted in inferior yields (Table 1, entries

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

• series of tri- and tetracoordinate phosphorus compounds using several basis sets and density functional theory (DFT) functionals gave a modest fit to experimental chemical shifts, but an excellent linear fit when plotted against the experimental values. The resultant scaling methods were then applied to

• best (mean absolute deviation/root mean square deviation (MAD/RMSD) = 6.9/8.5 ppm and 6.6/8.2 ppm, respectively), but for the full set of compounds gave higher deviations (MAD/RMSD = 8.2/12.3 ppm), and failed by over 60 ppm for a three-membered phosphorus heterocycle. Use of the M06-2X functional for

• /RMSD = 6.9/8.5 ppm and 6.8/9.1 ppm, respectively, over an experimental chemical shift range of −181 to 356 ppm. Due to the unexplained failures observed, we recommend use of more than one method when looking at novel structures. Keywords: calculations; DFT; phosphorus NMR; scaling methods

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• orientations towards the phosphorus lone electron pair (LEP). A comparison of DFT calculations and X-ray diffraction data is presented, herein we show which conformations are preferred for a given ligand. Keywords: DFT calculations; multi-ferrocenyl compounds; phosphorus thioesters; trithiophosphite; X-ray

• phosphines, a relatively small number of trivalent phosphorus derivatives has been used to construct multiferrocene compounds. The use of ferrocene derivatives containing a phosphorus–sulfur bond is a promising direction, since coordination with a metal atom can occur both at the phosphorus and sulfur atoms

• [7]. It is important to know the conformational capabilities of such ligands for construction of such complexes [8][9][10][11]. However, to date, XRD data on phosphorus derivatives containing a ferrocenyl substituent at the sulfur atom are presented only in oxidized and sulfurized forms

Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts

• Karen R. Winters and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154

• Karen R. Winters Jean-Luc Montchamp Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, United States 10.3762/bjoc.18.154 Abstract A series of P-stereogenic chiral phosphorus acids (CPAs) were synthesized to determine the requirements for efficient

• the thiophosphorus acids was disappointing for this reaction, the work should be useful for developing structural design elements. Keywords: asymmetric; heterocycles; organocatalysis; phosphorus; synthesis; Introduction The importance of asymmetric organocatalysis was demonstrated by the 2021 Nobel

• Prize in Chemistry awarded to McMillan and List. A subclass of organocatalysts introduced independently by Akiyama and Terada in 2004 [1][2], are the C2-symmetrical chiral phosphorus acids (CPAs) initially derived from the BINOL scaffold, and later extended to other scaffolds such as VAPOL [3] and

Dissecting Mechanochemistry III

• Lars Borchardt and
• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

• Margetić used dibrominated polycyclic imides as substrates to generate reactive alkenes, which could be trapped in situ by several dienes through Diels−Alder cycloadditions by ball milling (Scheme 3) [7]. Further, Moores and co-workers synthesized phosphorus-bridged heptazine-based carbon nitrides (g-h-PCN

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• ]. In tripodal molecules, three functional arms are bound to a central trivalent scaffold, which can be a single atom (e.g., carbon, nitrogen, or phosphorus), a small ring (usually aromatic or saturated six-membered ring), or a macrocycle (Figure 1a). The functional properties of tripodal molecules are

Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase

• Sanaz Ahmadipour,
• Alice J. C. Wahart,
• Jonathan P. Dolan,
• Laura Beswick,
• Chris S. Hawes,
• Robert A. Field and
• Gavin J. Miller

Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142

• = red, phosphorus = purple, chlorine = green, hydrogen = pink. C6–Cl is the gg rotamer (from the Cl6–C6–C5–O5 torsion angle). GMD function with probe 19 over 120 min (GMD (100 µg/mL), GDP sugars (50 µM), NAD+ (200 µM)). Dotted trace dictates expected fluorescence output following spiking with GDP-Man 1

Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes

• Almaz A. Zagidullin,
• Farida F. Akhmatkhanova,
• Mikhail N. Khrizanforov,
• Robert R. Fayzullin,
• Tatiana P. Gerasimova,
• Ilya A. Bezkishko and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139

• ; electrochemical properties; phosphacyclopentadienide anion; phosphaferrocene; phosphonium salt; phosphorus heterocycle; Introduction Among the various heterometallocenes reported to date, phosphaferrocenes are by far the most investigated because of their structural and electronic features [1][2] and remain the

• objects of growing interest in the fields of coordination chemistry [3][4][5] and asymmetric catalysis [6][7]. Due to the sp2-hybridization of the phosphorus atom, phosphaferrocenes are commonly regarded as phosphorus ligands with weaker σ-donor character than classical tertiary phosphines and stronger π

• mediator in the synthesis of asymmetric phosphines starting from white phosphorus [15]. Moreover, the presence of the lone pair of the P atom opens the route to polynuclear complexes [16][17][18] and coordination polymers [19][20][21] with the mixed σ-/π-coordination mode, which is not typical for

Dienophilic reactivity of 2-phosphaindolizines: a conceptual DFT investigation

• Nosheen Beig,
• Aarti Peswani and
• Raj Kumar Bansal

Beilstein J. Org. Chem. 2022, 18, 1217–1224, doi:10.3762/bjoc.18.127

• which their observed relative dienophilic reactivities could be rationalized. Besides, the Fukui functions of the carbon/nitrogen and phosphorus atoms of the >C=P– and –N=P– functionalities were also computed which revealed their hard electrophilic character and accorded well with the dienophilic

• of 1-aza-2-phosphaindolizines 3 with DMB and isoprene occurred at rt, although slowly and were speeded up by the use of sulfur or selenium which oxidized the phosphorus atom of the initially formed product thereby pushing the reaction in the forward direction [14]. The difference in the reactivities

• As discussed earlier, the descriptor Fukui function was developed to determine the hard/soft character of the reactive site in a molecule [19][20][21]. The Fukui functions at the carbon/nitrogen and phosphorus atoms of the >C=P– or –N=P– functionality of 2-phosphaindolizines calculated from the

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• , mechanochemical synthesis of phosphorus-bridged heptazine-based carbon nitrides (g-h-PCN). The structure of these materials was determined through a combination of powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), 31P magic angle spinning nuclear magnetic resonance (MAS NMR), density

• -PCN300) show a reduction in photoluminescent recombination, as well as a nearly two-time increase in photocurrent under broad spectrum irradiation, which are appealing properties for photocatalysis. Keywords: carbon nitride; density functional theory; mechanochemistry; phosphorus; photochemistry

• ; Introduction The development of heteroatom-doped graphitic carbon nitrides (g-CN) has been a rapidly growing area of research since their first report towards water splitting in 2009 [1]. Since that time, the addition of elements such as boron [2], phosphorus [3][4][5], sulfur and oxygen [6] have shown to help

Lewis acid-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence to access phosphoric esters

• Jin Yang,
• Dang-Wei Qian and
• Shang-Dong Yang

Beilstein J. Org. Chem. 2022, 18, 1188–1194, doi:10.3762/bjoc.18.123

• with highly air-sensitive and hazardous phosphorus halides, with the assistance of a suitable base [19][20][21][22][23][24]. As an alternative pathway, the phospha-Brook rearrangement [25][26][27][28][29][30] represents a green approach to phosphoric esters since it uses α-hydroxyphosphonates, which

• catalyst through a similar transformation under solvent-free conditions [44]. Recently, Zhang’s group disclosed a cesium carbonate-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence and extended the phosphorus source from phosphate to phosphonate [45]. Despite of these important advancements

• 3ai was obtained in 21% yield, while the meta-methyl-substituted derivative 1h was converted into the corresponding product 3ah in 63% yield. In addition, the configuration of 3ak was determined by an X-ray crystallographic analysis (CCDC 2177793). To our delight, phosphorus sources containing a

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• China 10.3762/bjoc.18.90 Abstract γ-Phostams include γ-phosphonolactams and γ-phosphinolactams and their fused derivatives, phosphorus analogues of γ-lactams. They are 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides and important biological five-membered azaphosphaheterocycles. They have

• [1][2][3][4][5][6][7][8] and have been widely applied in agrochemicals, medicinal agents, and materials science [9][10]. They are also organic synthetic intermediates and building blocks [7][11][13]. 1,2-Azaphosphaheterocycle oxide derivatives, phosphonolactams and phosphinolactams, are phosphorus

• analogues of the corresponding lactams [11][12][13][14]. 1,2-Azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides, also called γ-phosphonolactams and γ-phosphinolactams, and their fused derivatives are important five-membered 1,2-azaphosphaheterocyclic derivatives. They are γ-phostams, phosphorus

A trustworthy mechanochemical route to isocyanides

• Francesco Basoccu,
• Federico Cuccu,
• Federico Casti,
• Rita Mocci,
• Claudia Fattuoni and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 732–737, doi:10.3762/bjoc.18.73

• formamide with POCl3 in the presence of a base. Apart from phosphorus-mediated compounds, phosgene or diphosgene [18] work well, despite being still affected by the same limitations of POCl3. Therefore, organic chemists decided to move to other safer shores, so different dehydrating agents were also

Direct C–H amination reactions of arenes with N-hydroxyphthalimides catalyzed by cuprous bromide

• Dongming Zhang,
• Bin Lv,
• Pan Gao,
• Xiaodong Jia and
• Yu Yuan

Beilstein J. Org. Chem. 2022, 18, 647–652, doi:10.3762/bjoc.18.65

• and 3). Different copper salts were tested and the reactions proved to be less efficient (Table 1, entries 4 and 5). Except for triethyl phosphite, the reaction could not be carried out with other phosphorus species (Table 1, entries 6–8). The optimum result was obtained when benzene was employed as

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

• Qiuxin Zhang,
• Weiyi Tan and
• Bing Xu

Beilstein J. Org. Chem. 2022, 18, 159–166, doi:10.3762/bjoc.18.17

• the designed peptides combines solution synthesis of the enzyme trigger or the fluorophore with the solid-phase synthesis of the pyrrole-peptide conjugates. We used phosphorus pentoxide and phosphoric acid to react with ᴅ-tyrosine, ʟ-tyrosine, ʟ-serine, or ᴅ-serine to produce ᴅ-phosphotyrosine, ʟ

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• [57][58][59][60][61][62][63][64][65]. Results are summarized in Table 2. Triphenylphosphine and triethyl phosphite could be used interchangeably in the sulfur extrusion step. However, in most cases the co-elution of enaminones 15 with phosphorus-derived byproducts during chromatographic purification

• was unavoidable, and multiple chromatographic separations reduced the isolated yields. Such contamination with phosphorus-containing byproducts is a well-known problem in Eschenmoser condensations [30]. With particularly difficult separations we simply subjected the impure intermediates (for most of

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

• Azra Kocaarslan,
• Zafer Eroglu,
• Önder Metin and
• Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

• , we present a novel synthetic methodology for the photoinduced CuAAC reaction utilizing exfoliated two-dimensional (2D) few-layer black phosphorus nanosheets (BPNs) as photocatalysts under white LED and near-IR (NIR) light irradiation. Upon irradiation, BPNs generated excited electrons and holes on

• molecular properties of the intermediates and final products were evaluated by spectral and chromatographic analyses. Keywords: black phosphorus; click chemistry; heterogeneous photocatalyst; near infrared; phosphorene; Introduction For the last decade, click chemistry has been recognized as an

• black phosphorus (BP), the most stable allotrope of phosphorus, has been shown as a highly efficient photocatalyst possessing superior features in many respects [36][37]. BP, a vital semiconductor 2D material with excellent physicochemical properties such as high carrier mobility, tunable optical