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

• metal catalyst X2M into an aromatic C–H bond of a substrate (generally facilitated by the presence of a directing group (DG)), delivers a metal–aryl complex. Coordination and subsequent insertion of an alkene into the M–aryl bond then provides the desired coupling product after β-hydride elimination

• undergoes cyclometalation via a concerted metalation–deprotonation (CMD) process furnishing a cyclometalated intermediate. Thereafter, coordination and subsequent insertion of the alkyne into the Co–C bond delivers a seven-membered cobaltacycle. The desired coupling product is then liberated by reductive

• single electron-transfer process (Figure 36). In the first place, a bidentate chelated species is formed by the coordination of 1-naphthylamine derivatives with copper salt. The subsequent oxidation of this intermediate with potassium persulfate produces a Cu(III) species, furnishing a radical cation on

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

• still valid nowadays [33], although only the first intermediate (I) has been isolated and characterized [34]. However, contributions by Nakamura, Pericàs, and others support the initial proposal both experimentally and theoretically [35][36]. Firstly, two coordination vacancies are freed after the

• 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

• -oxide (TMANO), and dimethyl sulfoxide (DMSO). Once a new coordination vacancy has been opened on one of the cobalt centers, coordination of the olefin sets the stage for the subsequent C–C bond forming steps. The olefin is inserted into the less hindered Co–C bond, determining both the regio- and

Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• geometrical shapes that describe common coordination patterns (linear, trigonal planar, tetrahedral, trigonal bipyramid and octahedral) around central (usually metal) atoms. Neither the Lewis nor the VSEPR model is universally successful but they provide a conceptual basis for understanding and communicating

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

• (type I excitation). The direct VB-to-LUMO or VB-to-ligand transition is also enabled and produces a hypsochromic shift in the HPCat absorption spectrum. An excellent review of coordination chemistry controlled design of heterogeneous photocatalysis has been published by Xiong and co-workers, and we

• ][188][189][190]. Supramolecular photocatalysts are an interesting class of materials which utilise non-bonding interactions to control photochemical processes, a biomimetic strategy that imitates enzyme catalysis [191]. Supramolecular self-assemblies and coordination polymers based on perylene diimide

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

• proximity to each other, prone to be engaged in a bidentate-type metal-coordination complex [75]. 2.2 Synthesis of phenanthridines via photocatalyzed C–N bond formation As mentioned in the introduction, the examples gathered here involve the intermediacy of N-centered radicals. As a representative case, the

In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions

• Liwei Cao,
• Mikhail Kabeshov,
• Steven V. Ley and
• Alexei A. Lapkin

Beilstein J. Org. Chem. 2020, 16, 1465–1475, doi:10.3762/bjoc.16.122

• transition metal coordination sphere; the energy of a new M–C bond formed and the thermodynamic stability of organometallic product. With new developments in computational chemistry, mechanistic studies using density functional theory (DFT) provide valuable insights into the reactivity of organometallic

Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor–acceptor cyclopropanes

• Grzegorz Mlostoń,
• Mateusz Kowalczyk,
• André U. Augustin,
• Peter G. Jones and
• Daniel B. Werz

Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109

• thioketones 8 in the presence of a Lewis acid was based on the assumption that the coordination of the catalyst by two ester groups activated the cyclopropane ring and allowed a nucleophilic attack of the C=S group on the benzylic position of the cyclopropane derivative (Scheme 4). The subsequent ring-closure

Synthesis, antiinflammatory activity, and molecular docking studies of bisphosphonic esters as potential MMP-8 and MMP-9 inhibitors

• Abimelek Cortes-Pacheco,
• María Adelina Jiménez-Arellanes,
• Francisco José Palacios-Can,
• José Antonio Valcarcel-Gamiño,
• Rodrigo Said Razo-Hernández,
• María del Carmen Juárez-Vázquez,
• Adolfo López-Torres and
• Oscar Abelardo Ramírez-Marroquín

Beilstein J. Org. Chem. 2020, 16, 1277–1287, doi:10.3762/bjoc.16.108

• are well known. For example, the coordination of the P=O oxygen atom in bisphosphonates with a zinc cation in the catalytic site of the MMPs has been characterized, both through X-ray diffraction and molecular docking studies [11][36][37]. Consequently, we propose MMP-8 and MMP-9 as potential

• the carbon atom (C=O) of the ester group (Figure 3). In all cases, a distorted tetrahedral coordination geometry was observed for the zinc ion, caused by the chelation with His197, Glu198, and His207 residues. His201 was far apart from the catalytic site, and the basic nitrogen atom in this residue

• not aiming directly at the metal ion. However, it can be assumed that because of the flexibility of the protein in solution, the coordination to the metal ion would be possible. The targets 3 and 4 could coordinate the Zn2+ ion through the oxygen atom double bonded to the phosphorus atom (P=O) of one

Synthesis of pyrrolidinedione-fused hexahydropyrrolo[2,1-a]isoquinolines via three-component [3 + 2] cycloaddition followed by one-pot N-allylation and intramolecular Heck reactions

• Xiaoming Ma,
• Suzhi Meng,
• Xiaofeng Zhang,
• Qiang Zhang,
• Shenghu Yan,
• Yue Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2020, 16, 1225–1233, doi:10.3762/bjoc.16.106

• oxidative addition of the Pd(0) species to alkene intermediate 8a leads to Pd-complex I. Intramolecular coordination of Pd-complex I with the C–C double bond forms complex II which is followed by the syn insertion of alkene to give complex III [50][51]. Subsequent β-hydride elimination of III gives complex

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• proposed mechanism of Pd(II)-catalyzed C≡C oxidation is illustrated in Scheme 2 [33]: The catalytic cycle starts with the coordination of the electron-rich C≡C bond to the electron-deficient divalent Pd center, forming the corresponding π-complex (Int-A). Int-A smoothly undergoes nucleophilic attack by the

A smart deoxyribozyme-based fluorescent sensor for in vitro detection of androgen receptor mRNA

• Ekaterina A. Bryushkova,
• Erik R. Gandalipov and
• Julia V. Nuzhina

Beilstein J. Org. Chem. 2020, 16, 1135–1141, doi:10.3762/bjoc.16.100

• University of Central Florida for the inspiration, coordination and participation in the discussion of this project. Funding This work was supported by RFBR grant # 18-34-00898 mol_a. Author Contributions E. A. Bryushkova, E. R. Gandalipov and J. V. Nuzhina performed the experiments; E. A. Bryushkova

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• shorter than the sum of the van der Waals radii (2.67 Å) [51]. This suggest a close interaction between these two atoms, as observed in the crystal structure of 2c (see above). The analysis of other internal bond distances and angles in the coordination sphere of the Pd atom shows that they are similar to

• bridging CF3CO2 by monodentate NCMe probably destabilizes the compact dinuclear scaffold, thus helping the coordination and further reactivity of CO. Nevertheless, the reaction is slow because it took about 16 h to reach completion. The reaction temperature is also critical, since room temperature is

Pd-catalyzed asymmetric Suzuki–Miyaura coupling reactions for the synthesis of chiral biaryl compounds with a large steric substituent at the 2-position

• Yongsu Li,
• Bendu Pan,
• Xuefeng He,
• Wang Xia,
• Yaqi Zhang,
• Hao Liang,
• Chitreddy V. Subba Reddy,
• Rihui Cao and
• Liqin Qiu

Beilstein J. Org. Chem. 2020, 16, 966–973, doi:10.3762/bjoc.16.85

• acid. A gram-scale reaction of 1h with 2a went well and provided 3h with a slightly reduced yield and ee (75% yield and 73% ee, Scheme 3), compared with 3h in Scheme 1. According to the coordination of axial chiral phosphine ligands [65][66] and our analysis, we propose a possible intermediate

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• that have been introduced into the structure of the spirooxazine and spiropyran derivatives [17][18][19][20][21][22][23][24][25][26]. Regardless of whether the ring-opening reaction is induced by cations or irradiation, the coordination of metal ions to the substrate usually results in a negative

• styrylquinolinizium unit at the neighboring carbon atom C5’’. At the same time, imine groups also have a high binding affinity to Cu2+ [83][84][85] and Fe3+ [86][87] so that we propose the initial coordination of the metal cation mainly to the imine nitrogen atom of the spirooxazine group in the course of the

•  2), thus indicating that the initial coordination of the copper ion to the closed form of the spirooxazine was the rate-determining step of the reaction. And even though the NMR spectra (Figure 5) did not show any signals at δH > 9.5 ppm that would correspond to 2’’-H of the open merocyanine form

Copper catalysis with redox-active ligands

• Agnideep Das,
• Yufeng Ren,
• Cheriehan Hessin and
• Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

• exploring the possibility of a complementing metal-centered reactivity with electronic participation by the coordination sphere. To achieve this electronic flexibility, redox-active ligands can be used to engage in a fruitful “electronic dialogue” with the metal center, and provide additional venues for

• large number of alcohols (5a–e) in the presence of base (KOH 1 mol %). An interesting strategy aiming to explore the possibility of interfacing the redox-activity with H-bonding ability inside the ligand coordination sphere has been disclosed by Swart and Garcia-Bosch [16], and relies on the design and

• resulting copper complexes were synthesized and single crystal X-ray diffraction analysis evidenced the existence of H-bonding inside the coordination sphere of 6 (Scheme 3). The authors reported that the influence of the geometry of the complex on the H-bonding interactions as well as the nature of this

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

• ). This species serves as an active catalyst, nucleophilic at boron, via coordination with an alkene (307) which undergoes insertion to deliver the B–C bonded species via an intermediate that either undergoes elimination or reacts with an electrophile to form the product (e.g., 308, 309, Scheme 49) [92

• featuring a 1,4-borylation of α,β-unsaturated compounds 405 was reported by Hosomi in the presence of Cu(OTf)2·C6H6/(t-Bu)3P in DMF. No reaction occurred using (CuOTf)2·C6H6 in the absence of (t-Bu)3P. Mechanistic studies showed that the coordination of phosphorus(III) to Cu(I) accelerated the reaction, as

• coordination of (t-Bu)3P to CuCl is far greater than that with the diboron species, which results in an enhancement of the catalytic activity (Scheme 65) [128]. The one-pot borylation/protodeboronation of α,β-unsaturated ketones 405 in the presence of CuBr, B2pin2 and H2O as the hydrogen source was developed

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

• Zhenghui Liu,
• Peng Wang,
• Zhenzhong Yan,
• Suqing Chen,
• Dongkun Yu,
• Xinhui Zhao and
• Tiancheng Mu

Beilstein J. Org. Chem. 2020, 16, 645–656, doi:10.3762/bjoc.16.61

• ]. First, RhCl3·3H2O reacted with PPh3 to form Rh(PPh3)3Cl (A), followed by an oxidative addition of Rh(PPh3)3Cl (A) to the aryl iodide, producing the corresponding arylrhodium complex (B). Then, the coordination and insertion of CO led to the formation of benzoylrhodium complex (C). Next, metathesis with

Opening up connectivity between documents, structures and bioactivity

• Christopher Southan

Beilstein J. Org. Chem. 2020, 16, 596–606, doi:10.3762/bjoc.16.54

• of journal mandates for author inclusion of sequence accession numbers and somewhat later, pointers to genomic and expression data sets. This has needed herculean technical integration efforts not only from the NCBI Entrez system and the equivalent EBI resources but also global coordination by the

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• hydride species B. This transmetalation adds the silyl group to the phenoxy oxygen atom of the NHC ligand. The coordination of an α,β-unsaturated carbonyl compound 1 to the copper atom occurs in such a way that the bulky O-silyl group of the copper catalyst can avoid steric repulsions with the

• alkoxycarbonyl group of the substrate 1, forming π-complex C, and thus explaining the marked influence of the hydrosilane structure on the enantioselectivity. During this stereodetermining step, coordination of the phenoxy oxygen atom to the copper atom may render the chiral environment better defined. Then, the

Copper-catalyzed remote C–H arylation of polycyclic aromatic hydrocarbons (PAHs)

• Anping Luo,
• Min Zhang,
• Zhangyi Fu,
• Jingbo Lan,
• Di Wu and
• Jingsong You

Beilstein J. Org. Chem. 2020, 16, 530–536, doi:10.3762/bjoc.16.49

• reaction and referring to previous research results [30][31][32], a Cu(I)/Cu(III) catalytic cycle was proposed (Scheme 4). First, Cu(I) is formed by the reduction or disproportionation of Cu(II). Then, aryliodonium salt oxidizes Cu(I) to highly electrophilic Cu(III)–aryl intermediate I. The coordination of

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• coordination chemistry, and also valuable protecting or directing groups in catalysis [1][2][3]. 2-Oxazolines are a readily stable class of heterocycles resistant to a range of nucleophiles, bases, or radicals [4][5], which can be easily generated from amino alcohols and carboxylic acids, and from alkenes or

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• -heterocycles. This discussion seeks to paint a broad picture and consolidate different synthetic protocols and techniques for N-heterocyclic phosphine motifs. The introduction provides an account of P,N-phosphine ligands, and their structural and coordination benefits from combining heteroatoms with different

• coordination [12]. Thus, their use in catalysis is the basis of this review article with the main focus on the synthesis of N-heterocyclic phosphines. The presence of soft donor atoms such as phosphorus results in the formation of hemilabile ligands. These are multidentate ligands having hard P-donor and soft

• block for the assembly of homo and hetero-organometallic complexes. The 3- and 4-pyridylphosphine derivatives 5 have also been successfully used as templates for assembling supramolecular structures and coordination polymers [54][59]. Halogenated ring-fused pyridine reagents can also be used to generate

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• 22 upon coordination with the carbonyl oxygen atom of the amide group. The complex 22 then coordinated to the acrylate product 23, which rearranged to 24, and the β-hydride elimination of 24 yielded the desired olefinated product 21. C–H olefination of phenolic ethers: Based on Ackermann and co

[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

• retained its nucleophilic character. This allowed the coordination of an AlCl3 molecule to the C=C bond, which then became susceptible to an intramolecular nucleophilic attack by a sulfur atom. For α,β-alkenylphosphine sulfide 35, the conjugation of the double bond with thiophosphoryl fragment made the

• at the discovery of the transition state where the sulfur attack occurred at the β-carbon atom failed. It was possible that the electron density of the C=C double bond was slightly shifted towards the β-carbon atom due to possible interaction with the P=S fragment, and coordination of an AlCl3

• sulfide, which then underwent coordination of the second AlCl3 molecule, with an overall slight stabilization (+6.0/−8.5 kcal/mol). The adduct analogous to IV underwent methyl group migration to the β-carbon atom, along with the formation of a covalent Al–C bond. The last step required a remarkable