Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates

• Hisham Qrareya,
• Lorenzo Meazza,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 3008–3014, doi:10.3762/bjoc.16.250

• the real extrusion of CO in diaryl ketones [48][49] or of SO2 in diaryl sulfones (Scheme 1c) [50]. Nevertheless, a recent publication demonstrated that a metal-free photoextrusion was feasible when starting from benzene sulfonamides I (Scheme 1d, path a) [51]. Following the same approach, sparse

• the route to the extrusion of the phosphate moiety. This is demonstrated by the formation of a new emission band when more than one aryl group is present in the aryl phosphate (see Figure 1). In our investigation, we likewise stated that the formation of 5* (from 1 and 3) is highly favored in highly

• the presence of increasing amounts of TFE (up to 20% v/v, continuous line). Synthesis of biarenes via a) photogenerated triplet aryl cations and aryl radicals (PC = photocatalyst), b) intramolecular free radical ipso substitution, c) thermally catalyzed extrusion of CO and SO2, d) photoinduced

On the mass spectrometric fragmentations of the bacterial sesterterpenes sestermobaraenes A–C

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2020, 16, 2807–2819, doi:10.3762/bjoc.16.231

• and Scheme 1B. The loss of the isopropyl group C20–19–21 can be achieved by an inductive cleavage of 1•+ to g1•+ followed by an α-cleavage to h1+ (Scheme 1D). Starting from c1•+, two α-cleavages with the extrusion of ethylene can lead to i1•+ that upon a third α-fragmentation with loss of the methyl

Synthesis of purines and adenines containing the hexafluoroisopropyl group

• Viacheslav Petrov,
• Rebecca J. Dooley,
• Alexander A. Marchione,
• Elizabeth L. Diaz,
• Brittany S. Clem and
• William Marshall

Beilstein J. Org. Chem. 2020, 16, 2739–2748, doi:10.3762/bjoc.16.224

• into the final product, with extrusion of elemental sulfur) is not well understood and may be more complex, involving additional steps. The mechanism clarification of the reaction of tetrakis(trifluoromethyl)-1,3-dithietane (1) with azoles (and anilines) does require further investigation. As was

Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• extrusion of two carbon monoxide ligands from the starting cobalt species, allowing the alkyne group to bind to the cobalt metal centers. The subsequent coordination of the olefin counterpart requires the extrusion of a third carbon monoxide ligand, leading to pentacarbonyl complex II. This highly

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• involved the formation of a C(sp2)–C(sp2) bond via an aryl radical intermediate (Scheme 11). Thus, compound 11.1 was in situ converted to the corresponding diazonium salt 11.2+, which, upon reduction and nitrogen extrusion, formed the reactive aryl radical 11.3·. In turn, the latter radical smoothly

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

• Mingbing Zhong,
• Xavier Pannecoucke,
• Philippe Jubault and
• Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

• to the alkene, followed by the addition of SO2Cl to produce the desired product. However, when the reaction rate is slower, the SO2Cl anion decomposes to neutral SO2 and a chloride anion due to the weak nature of the Cu–SO2Cl bond. The SO2 extrusion explains the formation of the

A golden opportunity: benzofuranone modifications of aurones and their influence on optical properties, toxicity, and potential as dyes

• Joza Schmitt and
• Scott T. Handy

Beilstein J. Org. Chem. 2019, 15, 1781–1785, doi:10.3762/bjoc.15.171

• efficiency using an extrusion method. Of equal interest was that a highly qualitative photobleaching study indicated a significant degree of stability of these aurone-based dyes, with simultaneous or pre-mordanting offering better stability. Clearly further studies of the generality of this observation as

Synthesis of acylglycerol derivatives by mechanochemistry

• Karen J. Ardila-Fierro,
• Andrij Pich,
• Marc Spehr,
• José G. Hernández and
• Carsten Bolm

Beilstein J. Org. Chem. 2019, 15, 811–817, doi:10.3762/bjoc.15.78

• loads has led to mechanoenzymatic transformations [5][6][7], and to synthesize amino acid derivatives [8][9][10] and peptides [11][12][13] by ball milling and extrusion techniques. Similarly, mechanochemical derivatizations of sugars and sugar derivatives such as cyclodextrins (CDs) have proven

Low-budget 3D-printed equipment for continuous flow reactions

• Jochen M. Neumaier,
• Amiera Madani,
• Thomas Klein and
• Thomas Ziegler

Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50

• extrusion, we usually obtained channels about 100 µm smaller than set in the CAD drawing. The same effect was previously also encountered by others [28]. A smaller channel resolution than 200 µm is nearly infeasible because it repeatedly led to a blockage of the channels as previously observed by others as

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

• Yu Liu,
• Qiao-Lin Wang,
• Zan Chen,
• Cong-Shan Zhou,
• Bi-Quan Xiong,
• Pan-Liang Zhang,
• Chang-An Yang and
• Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

• of azide to Rh2(esp)2 complex (bis[rhodium-(α,α,α’,α’-tetramethyl-1,3-benzenedipropionic acid)]) and extrusion of N2. Then, the Rh-nitrene intermediate 65 goes through an intramolecular single electron transfer (SET) to give the nitrogen-centered radical intermediate 66 [87][88][89][90]. Next, the

Reactions of 3-(p-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway

• Akın Sağırlı and
• Yaşar Dürüst

Beilstein J. Org. Chem. 2018, 14, 3011–3017, doi:10.3762/bjoc.14.280

• trisubstituted acetonitriles into alkanes by the incorporation of KCN with the association of in situ-formed HCN and most likely through the extrusion of cyanogen which could not be detected or isolated. In addition, the plausible mechanisms were proposed for both transformations. The structures of the title

• . Then, the acidic hydrogen adjacent to the nitrile group in the intermediate product is sequentially abstracted by a CN− anion with the extrusion of an HCN molecule and a carbanion alpha to the nitrile group bearing a 1,2,4-oxadiazole ring is formed. The resulted carbanion undergoes a substitution

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• species (Figure 7, step a). Then (most likely) the aryl radical is obtained from the diazonium salt via the single electron transfer (SET) process and the inclusion of a graphene sheet (Figure 7, step b). This reaction step results in nitrogen extrusion. The desired functionalization route is most

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• carbene after extrusion of nitrogen and a crosslinked product after insertion reaction; X = e.g., NH, O, CH2. FimH crystal structure (pdb code 1KLF) with docked p-nitrophenyl α-D-mannopyranoside (1, pNPMan). FimH is a two-domain protein comprising a lectin domain (FimHL) with the carbohydrate binding site

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

• fragmentation to produce radical 132. The radical 132 could be trapped with iodine, giving iodide 133. The oxycarbenium ion 134 generated by the extrusion of iodide from 133 reacted with the acetoxy ion to furnish the resulting acetate derivatives. The acetates 130 and 131 were then treated with silylated

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• absence of light. Depending on the temperature, a new reaction pathway involving benzylic group migration, CO2 extrusion and final cycloaddition was proposed (Scheme 4). Kinetics and mechanism of thermal cycloaddition The kinetics and reaction mechanism of the thermal cycloaddition between 4-methyl-3

• bicyclic intermediate via a concerted [3 + 2]-cycloaddition followed by its very fast decomposition (extrusion of CO2) via a retro-Diels–Alder [4 + 2]-cycloaddition. The almost spontaneous extrusion of CO2 is caused by an energetically favorable aromatization occurring in this step leading to the formation

• of 3-phenylsydnone and proposed formation of N-phenylnitrilimine as the main reaction product via an internal ring closure, extrusion of CO2 and ring opening (Scheme 6). This very reactive 1,3-dipole was trapped by reaction with external (14C-labelled) CO2 to give 3-phenyl-1,3,4-oxadiazol-2(3H)-one

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

• compared by both experimental techniques and by means of MNDO calculations (Scheme 26) [131]. While the key steps for the thermal decomposition of tropones are electrocyclic ring closure and cheletropic CO extrusion to give an aromatic system, the cationic reactions occur with ring closure followed by the

From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• was achieved by fractional crystallization [24]. Chirality of the bisdioxine dicarbaldehyde, 2,6,9-trioxabicyclo[3.3.l]nona-3,7-diene-4,8-dicarbaldehyde, obtained by extrusion of water from triformylmethane, has also been demonstrated [25], and X-ray crystallography confirmed the structure of this

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• interestingly, when the reaction was performed using an aryl or alkylsulfonyl chloride, instead of trifluoromethanesulfonyl chloride, no extrusion of the SO2 moiety was observed, and the sulfonated products were recovered. The reaction mechanism involved excitation of the iridium catalyst under visible light to

• derivatives 9. It was found out that such compounds could take part in similar catalytic cycles, without CO extrusion, to yield trifluoromethylated isoquinolindione derivatives 10 in moderate to good yields (Scheme 9). Additionally, Zhang and co-workers reported once again that BiOBr nanosheet catalysis was

• (dtbbpy)]PF6 or Eosin Y favoured the introduction of the CF3 group and a chlorine atom, with SO2 extrusion. This phenomenon can be explained by the presumed ability of copper to coordinate SO2Cl− (intermediate 25), preventing it from decomposing into SO2 and Cl− and consequently allowing it to be

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

• trifluoromethanesulfinate CF3SO2Na that are commercially available at reasonable prices, are easy-to-handle sources of trifluoromethyl radicals. Remarkably, CF3SO2Na and CF3SO2Cl are multi-purpose reagents since they not only act as CF3 donors by extrusion of SO2, but also, under certain reaction conditions, the sulfur

• radical from CF3SO2Na with extrusion of SO2. Then, CF3• underwent a radical addition to the alkene to form the radical 29, which was trapped by the aryldiazonium salt to give the radical cation 30. Finally, 30 was reduced by [Ru(bpy)3]2+* to end up with the product 31 (Scheme 13). The

• generate the Ag(II) cation and the sulfate radical anion; then, the Ag(II) oxidised CF3SO2Na into CF3• with extrusion of SO2. The CF3 radical reacted with the C=C double bond of the cinnamamide leading to the intermediate 55 that underwent 6-endo trig cyclisation to 56 that finally aromatised to the

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

• Irwan Iskandar Roslan,
• Kian-Hong Ng,
• Gaik-Khuan Chuah and
• Stephan Jaenicke

Beilstein J. Org. Chem. 2017, 13, 2739–2750, doi:10.3762/bjoc.13.270

• abstraction, releasing the catalyst as In(OTf)2OH [102] and forming D. An intramolecular condensation reaction occurs which forms the desired product 5a with extrusion of MeOH. The In(OTf)3 is regenerated by TfOH with release of a water molecule, and the catalytic cycle is repeated. Conclusion We have

Spatial effects in polymer chemistry

• Helmut Ritter

Beilstein J. Org. Chem. 2017, 13, 2015–2016, doi:10.3762/bjoc.13.198

• the solid phase is not only influenced by external forces, for example, during extrusion, but is often also a result of chain mobility and strong intermolecular interactions. It should also be mentioned that the solubility of polymer chains is a spatial interplay between the solvent molecules and the

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

• of 14 can also proceed as a cheletropic extrusion of SO2 from 13 followed by recombination of SO2 with the formed carbanionic center. Similar fragmentations of such 1,3-dihydro-2,1-benzothiazol-2,2-dioxides and related compounds are known, but usually require heating to above 200 °C to yield aza

• -ortho-quinodimethane derivatives [44], which can rearrange into the corresponding Schiff bases by sigmatropic [1,5]-hydrogen shift [45]. In the case of 13, the extrusion of SO2 must be drastically accelerated due to its carbanionic nature, so that it can occur at 70 °C. The resulting anionic aza-ortho

A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes

• Grzegorz Mlostoń,
• Paulina Pipiak,
• Róża Hamera-Fałdyga and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 1900–1906, doi:10.3762/bjoc.13.185

• applied [14]. Another approach, which opens access to diverse ethenes, is the ‘two-fold extrusion reaction’, which comprises the [3 + 2]-cycloaddition of a diazo compound with a thiocarbonyl dipolarophile and subsequent elimination of N2 followed by sulfur extrusion [15][16][17]. In our continuing studies

Solvent-free sonochemistry: Sonochemical organic synthesis in the absence of a liquid medium

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 1850–1856, doi:10.3762/bjoc.13.179

• include techniques such as shearing [2], microfluidics [3] and twin screw extrusion [4][5][6]. More recently, sonochemistry has been included under the umbrella term of mechanochemistry [7] as it has demonstrated excellent potential when instigating chemical activity in solutions by applying mechanical

• ninhydrin and dimedone. Both systems were investigated in the complete absence of solvent and without the presence of any grinding media (such as inert silica beads) to help mediate the reaction. The aldol reaction was successfully carried out by twin screw extrusion, as I have reported previously [6]. The

• indicating that a complete reaction had taken place between a hydroxy group of ninhydrin and the activated methylene of dimedone (Figure 7). This reaction has previously been carried out by twin screw extrusion in the absence of solvent [6], and it was confirmed that the same product was obtained by both

18-Hydroxydolabella-3,7-diene synthase – a diterpene synthase from Chitinophaga pinensis

• Jeroen S. Dickschat,
• Jan Rinkel,
• Patrick Rabe,
• Arman Beyraghdar Kashkooli and
• Harro J. Bouwmeester

Beilstein J. Org. Chem. 2017, 13, 1770–1780, doi:10.3762/bjoc.13.171

• diphosphate and the pyrophosphate sensor, a highly conserved arginine located 43 amino acids upstream of the NSE triad, and the RY dimer, a highly conserved motif at the C-terminus. The substrate is ionised by extrusion of diphosphate, yielding a highly reactive allyl cation that can react in a cyclisation