Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• Avanzada (ORFEO-CINQA) and Instituto de Síntesis Orgánica (ISO), PO Box 99, 03080 Alicante, Spain 10.3762/bjoc.17.192 Abstract A series of novel palladium(II) and nickel(II) complexes of multifunctionalized aroylaminocarbo-N-thioylpyrrolinates were synthesized and characterized by analytical and

• , C. tropicalis, and C. glabrata standard strains. A deep conformational survey was monitored using DFT calculations with the aim to explain the importance of the final conformation in the biological experimental results. Keywords: antituberculosis; bidentate ligands; DFT; nickel; palladium

• results of its corresponding nickel(II) [18] and palladium(II) [19][20] complexes with the analogous tests obtained in the case of having a benzylic substituent at the same position. Also, DFT calculations are run in order to study the conformational analysis of the synthetized complexes. Results and

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• catalyst in the presence of a substrate possessing a prochiral migrating group or (2) stereospecifically by means of a chiral α-ketol. As an example of an enantioselective rearrangement, complexes of nickel(II) with a series of chiral 1,2-diaminopropane or pyridineoxazoline ligands were evaluated for their

• rearrangement. Nickel(II)-catalyzed enantioselective rearrangement of ketol 3 to form the ring-expanded and chiral product 4. Enantioselective ring expansion of β-hydroxy-α-dicarbonyl 6 catalyzed by a chiral copper-bisoxazoline complex. Enantioselective rearrangement of ketols 9 and 12 and hydroxyaldimine 14

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• esterified pyridines 29 in moderate to high yield. It is worth noting that 1,3-enynes 28 bearing internal alkyne moieties were not tolerated as substrates. In 2016, Aïssa and co-workers reported a nickel-catalyzed [4 + 2]-cycloaddition of 3-azetidinones 30 with 1,3-enynes 31 for the synthesis of 3‑hydroxy

• -4,5-alkyl-substituted pyridines 33 (Scheme 11) [53]. The transformation involved a two-step sequence of successive reactions: Firstly, the nickel-catalyzed [4 + 2]-cycloaddition of 1,3-enynes 31 and N-Ts-substituted 3-azetidinone 30 afforded dihydropyridinones 32 in good yield. The next step involved

• chalcogenoamination. The derivatization of 5‑selenyl- and 5-sulfenyl-substituted nicotinates. The tandem reaction of nitriles, Reformatsky reagents, and 1,3-enynes. Nickel-catalyzed [4 + 2]-cycloaddition of 3-azetidinones with 1,3-enynes. Electrophilic iodocyclization of 2-nitro-1,3-enynes to pyrroles. Electrophilic

Synthesis of O⁶-alkylated preQ₁ derivatives

• Laurin Flemmich,
• Sarah Moreno and
• Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

• potassium sodium tartrate solution (Rochelle salt) to furnish the aldehyde 5. Then, transformation of the 7-formyl into the 7-aminomethyl group proceeded via oxime formation, applying hydroxylamine hydrochloride in methanolic ammonia, followed by reduction with Raney nickel to yield the tritylated precursor

• ) hydroxylamine hydrochloride (21 mg, 0.300 mmol) was added. A clear solution was obtained shortly thereafter. The reaction was stirred for two hours at room temperature. Tetrahydrofuran (4 mL) and damp Raney-Nickel (approximately 200 mg) were introduced and the reaction was continued for one hour. The reaction

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• metallaphotoredox catalysis enabled C‒H functionalizations with unique reaction pathways under mild reaction conditions. Given the relative earth-abundance and cost-effective nature, nickel catalysts for photoredox C‒H functionalization have received significant attention. In this review, we highlight the

• developments in the field of photoredox nickel-catalyzed C‒H functionalization reactions with a range of applications until summer 2021. Keywords: C–H activation; functionalization; nickel; photocatalysts; photoredox; visible light; Introduction During the last decades, transition-metal-catalyzed

• of synthetic routes for modern pharmaceuticals [21][22]. Over the past two decades, nickel has emerged as an attractive alternative to palladium due to its relative earth-abundance, less toxicity, and inexpensiveness. Despite the fact that the nickel-catalyzed cross-coupling reactions represent a

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• ] cyclotrimerization reactions in the presence of nickel and cobalt catalysts [38]. First, they employed diyne 15 in the reaction with a series of alkynes (16) or nitriles (17) bearing a variety of functional groups including alkyl and alkene chains, hydroxy groups, and benzene and pyridine rings, to achieve the

• oxidative benzannulation reactions of 1-adamantoyl-1-naphthylamines with internal alkynes. Gold/bismuth-catalyzed cyclization of o-alkynyldiarylmethanes. [2 + 2 + 2] Cyclotrimerization reactions with alkynes/nitriles in the presence of nickel and cobalt catalysts. Cobalt-catalyzed [2 + 2 + 2

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• obtained triazoles 178 were then transformed into the corresponding 5-aminotriazoles 179 by reduction with Raney nickel in MeOH at 60 °C. In addition, the further transformation of 5-aminotriazoles 179 into more complex derivatives, such as 180–183, was explored [68]. The Huisgen reaction of structurally

Copper-mediated oxidative C−H/N−H activations with alkynes by removable hydrazides

• Feng Xiong,
• Bo Li,
• Chenrui Yang,
• Liang Zou,
• Wenbo Ma,
• Linghui Gu,
• Ruhuai Mei and
• Lutz Ackermann

Beilstein J. Org. Chem. 2021, 17, 1591–1599, doi:10.3762/bjoc.17.113

• ] auxiliaries (Figure 1a). Besides, the cobalt(II)- [31] or nickel(II)-catalyzed [32][33], pyridine oxide (PyO)-directed tandem alkynylation/annulation was realized by Niu and Song et al., which also provided the 3-methyleneisoindolin-1-one scaffolds (Figure 1b). Notably, a sustainable cupraelectro-catalyzed

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

• ]. Nickel catalysis is a viable alternative for this kind of cross-coupling reactions due to its particular radical mechanism, instead of the common metal-oxidative addition to organohalides [102][103][104]. Examples of the coupling between primary, secondary, and even tertiary alkyl halides with

• olefins 84 as nucleophile partners and racemic secondary and tertiary α-bromo-N-protected β-lactams 83 under nickel catalysis, along with the chiral bis(oxazoline) ligand 85 and triethoxysilane (Scheme 32) [108]. Substrate structural variations on 84 had only a small impact on the reaction

One-step synthesis of imidazoles from Asmic (anisylsulfanylmethyl isocyanide)

• Louis G. Mueller,
• Allen Chao,
• Embarek AlWedi and
• Fraser F. Fleming

Beilstein J. Org. Chem. 2021, 17, 1499–1502, doi:10.3762/bjoc.17.106

• electrophiles to afford imidazoles. In situ cyclization to the imidazole is promoted by the conjugate acid, hexamethyldisilazane, which facilitates the requisite series of proton transfers. The rapid formation of imidazoles and the interchange of the anisylsulfanyl for hydrogen with Raney nickel make the method

• to substituted imidazoles. Raney nickel hydrogenolysis was effective in interchanging the C4 anisylsulfanyl group for hydrogen (Scheme 3); attempted lithium–anisylsulfanyl exchange [19] or palladium- [22] or nickel- [23] anisylsulfanyl cross coupling was not successful. Raney nickel reduction of 7f

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• obtained structures of the free base bromo derivative 1 and discuss the nickel(II) bromo derivative 2 [27] and the free base iodo derivative 3 [22] from the CSD [25]. Additionally, we have included the substituted derivative of 2 with an acetylene moiety (2A) to investigate the differences observed between

• pointing towards the phenyl rings in a ↑↓↑↓ repeating pattern (Figure 2C). However, in this structure, there is no evidence for halogen bonding. By the addition of a nickel(II) metal center to compound 1, we obtain the structure of compound 2 [27]. In this structure a variety of changes in the overall

• . This is seen as a general decrease in the bond lengths, bond angles, and core size, corresponding to a significant increase in atom displacement and pyrrole tilt angles. This is essentially due to the ruffling caused by inserting a nickel(II) center [20][29][30][31] and is reflected in the NSD by a

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• reported by Lebel et al. [52] and McMorran et al. [53], both using overnight heating in acidic aqueous conditions (Scheme 22). The authors reported moderate to good product yields, and the final compounds found applications as intermediates for dynamic materials [52] and ligands for nickel complexation [53

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• [76]. Cases of C–P bond construction employing photoredox [77][78] or photoredox/nickel dual catalysis [79] have been identified in the field of photochemistry. However, here we introduce the methods initiated by EDA complexes for C–P bond construction. In 2018, Lakhdar and colleagues [44] reported a

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• , glycolysis of PET was performed under microwave heating in the presence of Zn(OAc)2, yielding BHET with an 80% selectivity at 97% conversion due to formation of dimers (Table 2, entry 7) [203][204]. Soluble metal chlorides (zinc, magnesium, iron, zirconium, cobalt, nickel) were also explored as catalysts in

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• cleavage by the use of either palladium(II) oxide or Raney nickel as the catalyst (Scheme 66) [116]. Butylbenzene (152) and 2-fluoro-1-phenylbutane (153) were the main products, although the unsaturated intermediates 154 and 155 were also detected. The contribution of the fluorine substituents to the

• lengthening and weakening of the C2–C3 bond of the cyclopropane ring appeared to dictate the regioselectivity. Monofluoroalkenes 157 were formed from the reductive ring opening of gem-difluorocyclopropanes 156 with dimethylamine·borane and catalyzed by nickel(II) fluorido complexes (Scheme 67) [117]. 1

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• -sulfinyl nitrone 20 with allylmagnesium bromide in the presence of AlCl3 provided a mixture of allylpiperidines (+)-21a and its isomer (+)-21b with 54% and 6% yield, respectively. The treatment of (+)-21a with nickel(III) oxide followed by dipolar cycloaddition of the resulting nitrone 22a, furnished the

• azatricyclo[3.3.1.1]decane (+)-23a in 54% yield. Treatment of (+)-23a with Raney nickel resulted in the cleavage of the sulfinyl group and the N–O bond, providing the bicyclic alcohol 24, which was oxidized with PCC to give (+)-euphococcinine (2). The same protocol was applied to (+)-21b, furnishing the

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• hydrodesulfurization with Raney nickel as catalyst and subsequent catalytic hydrogenation produced (±)-cuparene (13) in 90% yield. All-carbon [3 + 2] annulation in natural product synthesis The all-carbon [3 + 2] cycloaddition demonstrated the ability to assemble intricate polycyclic structures in the synthesis of

Easy access to a carbohydrate-based template for stimuli-responsive surfactants

• Thomas Holmstrøm,
• Daniel Raydan and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2020, 16, 2788–2794, doi:10.3762/bjoc.16.229

• glucosides with O-methyl groups (6), O-n-propyl groups (7) or O-n-dodecyl groups (8) were synthesized demonstrating that the building block could easily be functionalized with lipophilic tails of different lengths. The azido groups of the three compounds could undergo a reduction by using Raney nickel in

Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• diffraction X-ray diffraction (XRD) measurements were performed using a Rigaku ULTIMA IV diffractometer equipped with Cu anticathode (λKα = 1.5418 Å), Soller slits to limit the divergence of X-ray beam and a nickel foil filter to attenuate the CuKβ line. XRD patterns were recorded in the range of 3–50° (scan

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• /def2SVP level of theory (for details see Supporting Information File 1) revealed that the thermodynamically most stable structure is a trans configuration, where each of the pyridine units coordinate the nickel of the opposite porphyrin. Reductive cleavage of 1g by catecholeborane yields the

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

Convenient access to pyrrolidin-3-ylphosphonic acids and tetrahydro-2H-pyran-3-ylphosphonates with multiple contiguous stereocenters from nonracemic adducts of a Ni(II)-catalyzed Michael reaction

• Alexander N. Reznikov,
• Dmitry S. Nikerov,
• Anastasiya E. Sibiryakova,
• Victor B. Rybakov,
• Evgeniy V. Golovin and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2020, 16, 2073–2079, doi:10.3762/bjoc.16.174

• . Hydrogenation in the presence of Raney nickel or Pd/C in various solvents leads to a mixture of products, among which 8 and 9 are identified (Scheme 1). A satisfactory yield of the desired product 7 (78% by 31P NMR of reaction mixture) was achieved when the hydrogenation was carried out in acetic acid in the