Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• CO insertion (295) and transmetalation with palladium hydride to afford the acylpalladium species 296 (Scheme 71B) [122]. Utilizing a non-precious transition metal as an alternative for Pd, Yoshikai and co-workers (2020) reported the cooperative cobalt/Lewis acidic AlMe3-catalyzed hydrocarboxylation

• of the conjugated alkyne 374 to give cis-methyl cinnamate (375) in moderate yield via cobalt–hydride species (Scheme 82A) [139]. Similarly, Liu and co-workers (2023) utilized Ni to catalyze partial hydrogenation of conjugated alkynes to generate the corresponding trans-cinnamate esters 44 and 376 via

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• -controlled regio- and enantioselective hydroalkylation reaction, enabling the divergent synthesis of chiral C2- and C3-alkylated pyrrolidines through desymmetrization of readily available 3-pyrrolines (Scheme 8) [31]. The cobalt catalytic system (CoBr₂ with modified bisoxazoline ligands) achieved asymmetric

• L9, and reagents, delivering enantioenriched 2-/3-alkyl-substituted pyrrolidines with excellent regio- and enantioselectivity (up to 97% enantiomeric excess). Radical-clock experiments and deuterium-labeled silane studies revealed that cobalt catalysis proceeded via irreversible Co–H migratory

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• first reacts with the aniline under cobalt(III) catalysis, and the resulting intermediate C then attacks the thionium ion A. Quinolines of general structure II are formed after the loss of methyl sulfide from intermediate D, followed by final cyclization of intermediate E (Scheme 8, path II

• , 5 mol %) [63], indium (as In2O3 nanoparticles, 5 mol %) [64], iron (as FeCl3, 20 mol %) [65], cobalt (as CoBr2, 10 mol %) [66], and nickel (as Ni(py)4Cl2, 15 mol %) [67] can act as metal catalyst for the 3CC reaction. In all these cases, the temperature was lower (usually between 60–80 °C) compared

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• [Os(tpy)2]2+/red-light irradiation system well-suited for large-scale manufacturing. In this way, the authors have also tested different osmium complexes in various well-established photocatalyzed reactions such as copper, palladium, cobalt, and nickel metallophotoredox couplings using red light

• . While transition metals such as copper, palladium, cobalt, and nickel are well-established in catalyzed cross-coupling reactions, J. Cornella et al. have highlighted the reactivity of main-group elements like bismuth, which can mimic transition-metal behavior through oxidative addition. In their recent

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• convenient methodology for global optimization, eliminating the necessity of a theoretical model. A reconfigurable automated flow platform integrating online HPLC monitoring was used for the cobalt-catalyzed aerobic oxidative dimerization of desmethoxycarpacine (6) to carpanone (7) in the presence of oxygen

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• functional versatility [44], and many of these resulting metal complexes are catalytically active [45][46][47]. These synthetic metalloporphyrins take inspiration from biological systems, such as hemes (iron complexes), chlorophylls (magnesium complexes), and vitamin B12 (cobalt complex). Contrary to

• hydrogen evolution reactions (HER). While metal corroles have been extensively studied as efficient electrocatalysts [100][121][122], no reports on metal-free corroles were available until 2020. Si and co-workers reported that cobalt and metal-free triarylcorroles bearing hydroxyethylamino groups exhibited

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• the cobalt complex yielded [2]rotaxane (yield: 19%). Before that, the inclusion complex structure was conventionally formed randomly, resulting in a much lower yield than that obtained by this method and indicating that this 19% yield represented a significant increase compared with that of

• conventional synthesis. A similar [2]rotaxane molecule bearing a Co complex exhibited ICD derived from the chirality of CD on the absorption band of the cobalt complex [37]. Afterward, numerous CD-based rotaxane syntheses were reported; they generally contained noncovalent-bond moieties on the dumbbell

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• Cu(II) salt. The cobalt-catalyzed peroxidation of cyclic compounds 21 by TBHP has been demonstrated (Scheme 11) [48]. There are three possible reaction pathways: the first starts with the oxidation of cobalt(II) by TBHP to form cobalt(III) and the tert-butoxy radical (step A). Next, the formed Co(III

• cleaved to yield the ketone radical F. The subsequent addition of alkene radical F and tert-butylperoxy radical A to alkenes 113 leads to the target product 115. Cobalt-catalyzed alkylation–peroxidation of alkenes 117 with 1,3-dicarbonyl compounds 116 and TBHP was developed (Scheme 40) [97][98]. Gram

• provides radical E. tert-Butylperoxy group transfer from Co(III)OO-t-Bu A to E gives the coupling product F, which gives the final three-component product 118 and releases the Co(II) catalyst. A copper(0)- and cobalt(II)-catalyzed difunctionalization of enynes 119 with the sp3 α-carbon of alcohols 120 and

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• benzylic position (Scheme 31). 1.3.2 Co-assisted anodic oxidation. In 2021, Xu and colleagues developed an electrocatalytic approach for the intramolecular oxidative allylic amination and C–H alkylation using cobalt–salen complexes as catalysts [43]. In this reaction, the cobalt catalyst [Co(II)] is first

• oxidized to [Co(III)]+ at the anode, while MeOH undergoes cathodic reduction to form MeO− and H2. The MeO− then deprotonates the carbamate, and the resulting conjugated base is oxidized by the cobalt–salen complex [Co(III)]+, generating an amide radical. This amide radical initiates radical cyclization to

• back to [Co(II)] at the anode (Scheme 32). Recently, two additional studies on cobalt–salen complex-induced (cyclo)additions were reported by the Kim [44] and Findlater groups [45]. By employing cobalt–salen as a catalyst, along with PhMeSiH2 and dimethoxypyridine as additives, n-Bu4NPF6 as the

Solvent-dependent chemoselective synthesis of different isoquinolinones mediated by the hypervalent iodine(III) reagent PISA

• Ze-Nan Hu,
• Yan-Hui Wang,
• Jia-Bing Wu,
• Ze Chen,
• Dou Hong and
• Chi Zhang

Beilstein J. Org. Chem. 2024, 20, 1914–1921, doi:10.3762/bjoc.20.167

• metal reagents, including cobalt [10], copper [11], rhodium [12][13][14], palladium [15][16][17], silver [18], and gold [19] catalysts, have been reported. However, compared to the widespread use of metal catalysts, the synthesis of isoquinolinone scaffolds mediated by environmentally friendly

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• achieve the total synthesis of 5 (Scheme 10A). Basic hydrolysis of the ester on the C1 side chain of 98 proceeded under mild conditions and furnished secondary alcohol 99. Subsequent oxidation of the two phenol rings of 99, catalyzed by the cobalt complex salcomine, afforded bisquinone 100. The subsequent

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• chromatographic purification due to much lower solubility of 4b compared to 4a. The metal complex of 4b with copper(II) was prepared, because copper(II) exhibited better extraction and separation abilities than cobalt(II) and palladium(II) in the case of Cu-tethered rectangular nanobrackets 1a [11]. Before SWNT

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• interest as the starting materials are inexpensive bulk chemicals and the reactions can be carried out under air without any particular precautions. Radical hydrochlorination reactions Cobalt and iron-promoted radical hydrochlorination reactions are part of the large family of metal hydride hydrogen atom

• the metal-catalyzed hydrochlorination of alkenes based on MH HAT reactions (Scheme 23) [80]. They discovered that a combination of a cobalt catalyst, a silane, and tosyl chloride promoted the hydrochlorination of terminal unactivated alkenes. The scope of the reaction is relatively broad when

• Syntheses [83]. The proposed catalytic cycle is shown in Figure 7 and involves the following steps. First, a cobalt hydride complex A is formed in situ from Co(II) complex and the silane. Then, regioselective alkene hydrocobaltation takes place. This step is highly regioselective, placing the cobalt atom on

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• decarboxylative cross-coupling (DCC) of NHPI esters with organometallic reagents, resembling classic Kumada, Negishi, and Suzuki couplings, has been enabled by nickel (Ni), cobalt (Co), iron (Fe), and copper (Cu) catalysts [84][85][86][87][88][89][90][91] (Scheme 23A). The typical mechanism begins by

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• ·H2O (Table 1, entries 2–9). To our delight, copper salts were effective, giving the desired product 3aa in excellent yields of 88–95% (Table 1, entries 7–9). Cuprous salts, cobalt chloride, and nickel acetate were partially efficient for the reaction, providing product 3aa in 85% yield (Table 1

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• 2,2'-dihalogenated biphenyls 4 as starting materials [24][25]. Although the cobalt-mediated alkyne trimerization route frequently used by Vollhardt and co-workers is not the first choice for the synthesis of the biphenylene itself, it has led to the synthesis of structurally demanding substituted

• biphenylenes and the emergence of a family of polycyclic hydrocarbons called [N]phenylenes. The utilization of cobalt-mediated alkyne trimerization facilitated the synthesis of [N]phenylenes exhibiting diverse structural configurations, including linear 7, angular 8, zig-zag 9, bent 10, branched 11, and cyclic

• steps (Scheme 15). The initial step involved the synthesis of compound 71 in 64% yield using a cobalt-catalyzed cyclotrimerization reaction between 1,2-diethynylbenzene (5) and bis(trimethylsilyl)acetylene (70), a method commonly employed in [N]phenylene synthesis. Subsequently, treatment of compound 71

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• concentration of this greenhouse gas by upcycling. Selectivity towards CO2-reduction products is highly desirable, although it can be challenging to achieve since the metal-hydrides formation is sometimes favored and leads to H2 evolution. In this work, we designed a cobalt-based catalyst, and we present herein

• selectivity from 6% to 97% after four hours of irradiation at 420 nm. Further efficiency enhancement was achieved by adding 1,1,1,3,3,3-hexafluoropropan-2-ol, producing CO with a TON up to 230, although at the expense of selectivity (54%). Keywords: carbon monoxide selectivity; cobalt(II) complex; copper(I

• [19][20][21], cobalt [22][23], and nickel [24][25], have been designed as CO2 reduction catalysts. This (supra)molecular approach is appealing for gaining a structure–property understanding with the goal of tunable and efficient activity. Among the 3d transition metals, cobalt is relatively abundant

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• of coordination compounds of copper(II), iron(II/III), manganese(II), nickel(II), and cobalt(II) with 9-Zn and 9-Cu was demonstrated. The emission quenching was rationalised considering the binding of the transition metal within the crown ether cavity. No quenching was observed upon the addition of

• precursor for coordination compounds. The following transmetallation with cobalt(II) produced an intriguing Pacman-like coordination compound 16-Co(II) (Scheme 6) [66]. The spontaneous oxidation of cobalt(II) to cobalt(III) resulted in modifying the cobalt cation coordination sphere from a distorted-square

• , accommodating the axially-positioned water molecule on the cobalt(III) centre. The latter assembled into a remarkable hexagonal wheel architecture when exposed to air in THF, as evidenced by XRD (Figure 12). The hexagonal wheel [16-Co(III)]6 was stabilised by intramolecular hydrogen bonding between the water

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• -(arylsulfenyl)succinimide 1 (Scheme 27) [62]. The reaction involves the formation of active cobalt species I from the interaction of KOAc with the cobalt pre-catalyst. Treatment of I with 63 resulted in the five-membered cobaltocycle complex II. Next, coordination of 1 to II gave III, followed by intramolecular

• nucleophilic trapping of the electrophilic SAr unit to furnish C2-sulfenylated product 65 and Co-complex IV. At last, active cobalt species I regenerated from IV in the presence of AcOH. It should be noted that when R = H, C2-sulfenylated product 65 may be sulfenylated via a thermal electrophilic aromatic

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

•  27) [88]. This route provides an environmentally friendly and practical approach to alkyl-substituted alkynes. Co-catalyzed reactions In recent years, cobalt has exhibited great application potential as a cross-dehydrogenation coupling catalyst due to its low price, environmentally friendliness, and

• unique catalytic behavior [89]. However, there are only a few examples of cobalt catalysis in CDC reactions. Limited by the activity of Co catalysts, there are few examples of Co-catalyzed reactions involving ether C(sp3)–H bond activation. The Co-catalyzed C(sp3)–C(sp3) CDC of glycine and peptide

• derivatives with THF was developed by Correa et al. (Scheme 28) [90]. This study presents a cost-effective cobalt-catalyzed C(sp3)–H functionalization strategy for α-aminocarbonyl compounds. The method allows for the direct introduction of ethers into a diverse range of glycine derivatives. Importantly, the

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• much more efficiently in decarboxylative RLT reactions than aliphatic acids [42]. Outside of decarboxylation, X. Peter Zhang recently reported the enantioselective synthesis of allylic amines through coupled HAT and RLT on allylic C–H bonds [45], using a bulky cobalt porphyrin complex developed and

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• , inorganic Z-schemes have used cobalt complexes and polyoxometalates to shuttle electrons between water oxidation and carbon dioxide reduction photocatalysts [2][4]. However, the photocatalysts of these systems are usually first developed separately with sacrificial electron donors. Other methods for

• employ redox mediators can use compounds such as cobalt bipyridine complexes which undergo fast reversible electron transfer reactions [2][4][8]. Z-schemes require a steady state concentration of both oxidized and reduced redox mediator species to allow an efficient shuttling of electrons between

• tris buffer rather than phosphate [44]. Instead of using the regenerated NADH in a photocatalytic system, this team actually used an enzyme to consume the regenerated NADH and check its viability. Robert and co-workers recycled the NADH analogue 1,4-BNAH using different photosensitizers and cobalt

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

• aromatization steps led to product 43 upon catalyst regeneration. Recently, Ryabchuk et al. [74] used the 3d-metal cobalt catalyst Co/NGr-C@SiO2-L under solvent-free conditions to synthesize various N-aryl-substituted pyrroles 45 in 50–88% yields from the corresponding nitroarenes 44 via the Clauson–Kaas

• reaction involving benign reducing agents H2 or HCOOH or CO/H2O mixtures (Scheme 21). The main advantage of this heterogeneous Co catalyst is that it can be used up to 10 times without significant loss of activity and the active cobalt hydride species selectively reduces nitroarenes to their corresponding