Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• powerful method for the introduction of a C1 building block into organic substrates using carbon monoxide, its surrogates, or compounds able to act as carbon monoxide sources [11]. In recent years, many groups have used the carbonylation approach for the synthesis and functionalization of indoles, which is

• carbon monoxide insertion, and Suzuki–Miyaura coupling reaction, from 2-gem-dibromovinylaniline [12]. In the presence of Pd(PPh3)4 (5 mol %) as catalyst, 5 equivalents of base (K2CO3), an aryl- or heteroarylboronic ester (1.1 equivalents), CO (12 bar), in dioxane at 100 °C after 16 h the indole

• derivatives were isolated with good yields (Scheme 1). Instead, in the Senadi et al. approach, 1-(3-amino)-1H-indol-2-yl)-1-ketones were obtained through a Pd(0)-catalyzed cascade process consisting of isonitrile insertion as carbon monoxide surrogate and a C–H cross-coupling [13]. The reaction took place in

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• hydrochlorination of 1-octene (63) required a combination of alumina and oxalyl chloride (Table 5, entry 3). It should be noted that this reaction needs to be carried out under a well-ventilated hood due to the evolution of toxic carbon monoxide. Kropp and co-workers observed that the remaining 2% of the alkene was

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

• ) that is labile. By default, the complex is in a closed form with the functional units on each ligand facing each other due to the square planar geometry of the complex. By adding a first ancillary ligand (carbon monoxide, chloride,…) that strongly binds to the metal center, one weak binding site is

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• π-CPCs relies on the extrusion of carbon monoxide (CO) from soluble precursors incorporating bridging ketone fragment(s). In contrast with the thermal activation required in retro-Diels–Alder reactions, photoirradiation of α-diketones triggers a Strating–Zwanenburg decarbonylation leading to the

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• was disclosed that DMF, the reaction solvent, could act as a potential carbon monoxide surrogate under certain circumstances, notably, in metal-catalyzed aminocarbonylation procedures [19][20]. Unfortunately, no DBDAP was obtained and we only observed the formation of intermediate 3a in 25% yield

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

• 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

• transition-metal-based complexes, the outcomes are generally two-electron reduction products, such as carbon monoxide (CO), formic acid (HCO2H), or formate (HCO2−). To mitigate the strong energetic requirements of the reaction shown in Equation 1, the reduction of CO2 occurs in the presence of protons, so

• -dimethylacetamide (DMA) as the major component. Although this solvent has very similar properties as the mostly used N,N-dimethylformamide (DMF), it is highly stable and does not produce formate upon hydrolysis [49]. In the solvent system DMA/TEOA 3:1 (v/v), we could observe that carbon monoxide was formed, however

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• blending compatibilizers [211]. Radical depolymerization capability can be incorporated at synthesis. Wang et al. introduced photodegradability to polyolefins by copolymerization of carbon monoxide [212]. Nevertheless, radical depolymerization is an essential tool to tackle the problem of polymer wastes

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

• commercialized. Specifically, the company Twelve are making large advances in the electrolysis of carbon dioxide to carbon monoxide. Their contracts started with materials and have now expanded to fuels [10]. However, industrial electrochemistry either requires a dedicated power source, or plugging into a

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

• interconnected photocatalytic cycles as the hydrodehalogenation, an aryl radical 2• is formed via successive PET and C(sp2)–X bond cleavage (Figure 17B). Carbon monoxide, introduced to the reaction mixture by a tube-in-tube reactor, traps the aryl radical to generate the acyl radical 23 (Figure 17B

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

• cyclopentenone motifs, by reaction of an alkene, alkyne, and carbon monoxide. This is only recently, in April 2022, that this reaction was reported to allow the formation of an eight-membered ring [81]. Indeed, Li and co-workers employed the Pauson–Khand reaction in order to undertake the total synthesis of

Practical synthesis of isocoumarins via Rh(III)-catalyzed C–H activation/annulation cascade

• Qian-Ci Gao,
• Yi-Fei Li,
• Jun Xuan and
• Xiao-Qiang Hu

Beilstein J. Org. Chem. 2023, 19, 100–106, doi:10.3762/bjoc.19.10

• of 1,2-difunctionalized arenes with alkynes or carbon monoxide (Scheme 1b, III) [13][14][15][16], have been widely applied for the assembly of isocoumarins over the past decades. Recently, the transition-metal-catalyzed ortho C–H activation/annulation of benzoic acids has emerged as an attractive

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• amine nucleophiles [139]. Following an iminyl radical-mediated intramolecular 1,5-cyclization, the subsequent alkyl radical could propagate across carbon monoxide, eventually terminating with an alkyl or aryl amine. In the following year, the Li group described an interesting radical cyclization of β,γ

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

• , high yield, the use of dimethyl carbonate as a sustainable solvent, the use of an efficient alternative source of carbon monoxide, and avoiding a pressurized cylinder are some benefits of this protocol (Scheme 35) [59]. A feasible mechanism is illustrated for the synthesis of 1,2,3-triazole-5

• sterically hindered 1-(2-bromophenyl)-1,2,3-triazole derivatives 130. The target compounds, triazolo[1,5-a]indolones 131, were then obtained from 130 in high yield using catalytic amounts of Pd(OAc)2 and PCy3, carbon monoxide, and potassium carbonate and with heating in toluene at 120 °C. The structure of

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

• ] and [3.4.0] bicyclic systems bearing two quaternary atoms at the bridgehead position [49]. For instance, enynol 110 was treated with 5 mol % of [RhCl(CO)2]2 and carbon monoxide to afford a [3.3.0] bicycle 111 in 87% yield (Scheme 8A). The proposed catalytic cycle of this elegant rhodium-catalyzed

• subsequent treatment with Waser’s reagent 116 [61] afforded alkyne 117 in 62% yield over two steps. Enyne 118, which was prepared in two steps from 117, was subjected to rhodium-catalyzed intramolecular [3 + 2] cycloaddition in the presence of carbon monoxide to give tricycle 119 bearing the desired vicinal

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

• between an alkyne, an olefin and carbon monoxide, resulting in the regioselective formation of a cyclopentenone derivative (Scheme 1) [18][19][20][21][22]. This cobalt-mediated reaction was initially discovered by Pauson and Khand in the early 70s [23][24][25] and has since become a powerful

• 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

• stereochemical outcome of the overall process. A carbon monoxide ligand then undergoes migratory insertion into one of the Co–C bonds in cobaltacycle V, followed by reductive elimination to release the final product (Scheme 3). As mentioned above, the regiochemistry of this transformation is, in most cases

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• found that KOH plays a crucial role in the formation of porosity. Metallic potassium is formed during the carbonization of the carbon precursor, which intercalates in the carbon structure and is responsible for further release of carbon dioxide, carbon monoxide and hydrogen [71]. According to Marsh and

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• platform for dual catalysis due to their ability to promote both metallocatalysis and photocatalysis in a one-pot system [36][37][38][39]. Martin and co-workers carried out the C–O bond cleavage of alcohols using a cobalt porphyrin under visible light irradiation and a carbon monoxide atmosphere (Scheme 11

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• three possible dissociation pathways that can be followed (Scheme 5). Moreover, Reilly and co-workers observed the decomposition of benzaldehyde (8) into benzene (21) and carbon monoxide (22) (reaction (3) in Scheme 5) after the irradiation at 258.9 nm via laser ionization mass spectrometry and

• electronic distribution and the spectroscopy of the excited states of benzaldehyde (8) have been examined. These studies illuminate the ways that the various excited states of benzaldehyde (8) decay, either through phosphorescence or through the dissociation to benzene (21) and carbon monoxide (22) or to a

• , and the followed pathway was the pathway described in reaction (1) of Scheme 5 [30]. In another study on the photochemical dissociation of benzaldehyde (8), Bagchi et al. detected two major routes, furnishing either a formyl radical (20, reaction (1) of Scheme 5) or carbon monoxide (22, reaction (3

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

• reprocessing of readily available industrial raw materials into more functionalized products. These processes generally utilize carbon monoxide (CO), currently the most important C1 building block used in numerous industrial carbonylation processes [6][7][8] and widely applied in industrial productions [9][10

Combination of multicomponent KA² and Pauson–Khand reactions: short synthesis of spirocyclic pyrrolocyclopentenones

• Riccardo Innocenti,
• Elena Lenci,
• Gloria Menchi and
• Andrea Trabocchi

Beilstein J. Org. Chem. 2020, 16, 200–211, doi:10.3762/bjoc.16.23

• [39][40], consisting of a [2 + 2 + 1] cycloaddition between an olefin, alkyne, and carbon monoxide. This reaction has been also applied in cascade approaches [41], and in combination with RCM [42], Diels–Alder [43] and Staudinger [44] reactions to produce novel structurally complex chemical entities

Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• carbon monoxide-releasing properties [27][28] of dicobalt hexacarbonyl alkyne complexes have been noted, and their medicinal potential has been summarized [29][30][31]. Despite developments, the collection of metallo-nucleosides is limited. Hybridization of alkyl and aryl-substituted alkyne cobalt

Vicinal difunctionalization of alkenes by four-component radical cascade reaction of xanthogenates, alkenes, CO, and sulfonyl oxime ethers

• Shuhei Sumino,
• Takahide Fukuyama,
• Mika Sasano,
• Ilhyong Ryu,
• Antoine Jacquet,
• Frédéric Robert and
• Yannick Landais

Beilstein J. Org. Chem. 2019, 15, 1822–1828, doi:10.3762/bjoc.15.176

• stirring bar, 1a (90.1 mg, 0.4 mmol), 2a (455.3 mg, 4.0 mmol), 3a (141.4 mg, 0.51 mmol), (Bu3Sn)2 (474.7 mg, 0.82 mmol), DTBHN (21.4 mg, 0.12 mmol), and 1,2-dichloroethane (8 mL) were placed in a stainless steel autoclave. The autoclave was closed, purged three times with carbon monoxide, pressurized with

• equipped with two sapphire glass windows and an inserted Pyrex glass liner. The autoclave was closed, purged three times with carbon monoxide, pressurized with 130 atm of CO and then irradiated by Xenon lamp (500 W) with stirring for 16 h. Excess CO was discharged after the reaction. The reaction mixture

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• [30]. The introduction of the aldehyde moiety is carried out through catalytic carbo-palladation reaction using molecular carbon monoxide in the presence of methyl formiate as hydrogen source in modest yield (35% and 19% for 8 and 10, respectively) due to the formation of a relatively large amount of

• %, 6: 30%; d) (3-(2-methoxyethoxy)prop-1-yn-1-yl)magnesium bromide, THF, 60 °C, 85%; e) carbon monoxide, sodium formiate, [Pd(PPh3)2Cl2], anhydrous DMF, 100 °C, 8: 19%, 9: 35%; f) cyanoacetic acid, piperidine, MeCN, CHCl3, 80 °C, BOD-TTPA: 34%, BOD-TTPA-alk: 26%. a) Absorption spectra of compounds BOD

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• , leading to final lactams 20. This mechanism is partially corroborated by the following multicomponent synthesis where benzamide 21, ortho-functionalized with a terminal alkyne group (Scheme 5), a secondary amine 22 and carbon monoxide (23) react to produce 3-methyleneisoindolinones 24 [80]. A palladium

• , 2-bromobenzaldehydes 62 and carbon monoxide (23) at atmospheric pressure, with the assistance of DABCO as base and tri(tert-butyl)phosphonium tetrafluoroborate as ligand (Scheme 19) [100]. A variety of substituents in the benzene rings (R1, R3) are compatible with the reaction conditions, but

• three-component reaction between aryl iodides, incorporating a Michael acceptor 105, amines and amides 2 and carbon monoxide (23) (Scheme 30) [108]. It is remarkable that not only aromatic but also aliphatic amines and even amides and sulfonamides can be used as the nitrogen-containing substrate. With

A novel and efficient synthesis of phenanthrene derivatives via palladium/norbornadiene-catalyzed domino one-pot reaction

• Yue Zhong,
• Wen-Yu Wu,
• Shao-Peng Yu,
• Tian-Yuan Fan,
• Hai-Tao Yu,
• Nian-Guang Li,
• Zhi-Hao Shi,
• Yu-Ping Tang and
• Jin-Ao Duan

Beilstein J. Org. Chem. 2019, 15, 291–298, doi:10.3762/bjoc.15.26

• compound C with a five-membered palladacycle. C undergoes the process of oxidative addition with ortho-bromobenzoyl chloride to give the PdIV intermediate D, and E can be obtained via a reductive elimination reaction. A novel aryl-PdII species F is formed through removing carbon monoxide from E. Ultimately