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

• demonstrated the broad applicability of this photocatalytic system. It has to be noted that zinc-based photocatalysts with phthalocyanin ligands are not limited to energy-transfer pathways involving singlet oxygen generation. A recent work by Yoshimitsu et al. has shown that zinc(II)-based porphyrin complexes

• can engage in electron-transfer mechanisms to enable radical cascade reactions under red-light irradiation (Scheme 9) [37]. These zinc(II)-based porphyrin catalysts operate via an oxidative quenching cycle, directly facilitating the transfer of an electron from the excited state of the porphyrin to

• underscores the practicality and accessibility of the method, even outside a laboratory setting. The green chemistry metrics analysis provided in the study confirms the environmental benefits, with high atom economy, low waste generation, minimal resource consumption, and the potential of porphyrin

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

• (aromatic) organic heterocyclic systems, excluding calix[4]pyrroles, which are colorless and non-aromatic, as well as norcorroles, isophlorins, and the 16π oxidized form of porphyrin that exhibits anti-aromatic character (Figure 1a). Calix[4]pyrroles possess a nonplanar structure and a high degree of

• porphyrin macrocycle contains two Ns and two NHs (from two pyrrolenine and two pyrrole units), both of which can act as supramolecular H-bond donor and acceptors and can promote metal-free catalysis. Additionally, due to their synthetic versatility, these macrocycles can be further functionalized to add

• other binding sites required for substrate binding and/or promotion of the catalytic activity. Past studies have shown that modifying the porphyrin core with urea functionalities and amino acid substituents leads to the formation of ureaporphyrins, which significantly enhance sugar binding in non-polar

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

• oxidation of cyclohexane 83 with TBHP using mononuclear [77][78][79] and dinuclear [80] non-porphyrin iron complexes (Scheme 30). Besides the oxygen atom transfer products, cyclohexanol (85) and cyclohexanone (15), the formation of peroxide 84 was observed. Oxidation of cyclohexane (83) was also carried out

• bisperoxide 190 from styrene 189 is favoured under metalloporphyrin catalysis (Mn(III)-tetra(2,6-dichlorophenyl)porphyrin acetate) in basic media over traditional Kharasch copper catalysis (Scheme 60a). Acrylonitrile 192 was converted into bisperoxide 193 in 55% yield under Cu(OAc)2 catalysis (Scheme 60b) [91

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• –CH2–(CF2)n–COOCH3) with triflate as leaving group in terminal position are easily accessible and versatile building blocks for attaching long chain acids (pKa 0–1) to substrates in Williamson ether-type reactions. Keywords: acid-functionalized porphyrin; electron-rich porphyrin; nickel porphyrin

• ; perfluorinated aliphatic carboxylic acids; porphyrin synthesis; Introduction Metal porphyrins are prosthetic groups in a number of essential biomolecules, including hemoglobin, chlorophyll, and cytochromes, supporting processes such as oxygen transport, photosynthesis, and electron transfer [1][2][3][4][5

• electrocatalytic hydrogen evolution reactions, a proton source is needed [11]. In this context, trifluoroacetic acid is very frequently chosen as the proton source, because it is a strong acid but just not strong enough to destroy (demetallate) the Ni porphyrin [10]. Covalent attachment of acids facilitates proton

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• porphyrin architectures, which could be used in supramolecular assemblies, catalysis, or sensing. In this work a library of arm-extended dodecasubstituted porphyrins was synthesized through the optimization of the classic Suzuki–Miyaura coupling of peripheral haloaryl substituents with a range of boronic

• substrates in their void. Keywords: C–C coupling; conformational analysis; nonplanar porphyrin; Pd-catalysis; porphyrin; Introduction Porphyrins are tetrapyrrolic macrocycles that perform essential processes in nature, such as oxygen transport in hemoglobin and photosynthesis [1]. Porphyrins are often

• the porphyrin ring deforming from the mean porphyrin plane either by steric repulsion in the core of the macrocycle or by bulky substituents at the porphyrin periphery [3]. This affords four principle distortion modes, saddle, dome, ruffle or wave [8], which can be quantified by the normal-coordinate

Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions

• Hayato Takagi,
• Çetin Çelik,
• Ryosuke Fukuda,
• Qi Guo,
• Tomohiro Higashino,
• Hiroshi Imahori,
• Yoko Yamakoshi and
• Tatsuya Murakami

Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231

• Instutite for Liberal Arts and Sciences (ILAS), Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan 10.3762/bjoc.20.231 Abstract We have reported that upon visible light irradiation, ferrocene-porphyrin-[60]fullerene triad molecules yield long-lived charge-separated states, enabling the control of the plasma

• an acceptor in photoinduced charge-separation systems, we have previously employed ferrocene-porphyrin-C60 triad molecules (Figure 1a) in a biological system to control the plasma membrane potential (Vm) of living mammalian neuronal cells under photoirradiation [4][5][6]. Generally, Vm originates

• from a difference in electric charge on the two sides of the plasma membrane (approximately 5 nm thickness), with a slight excess of the positive ions inside relative to the negative ions outside. Our ferrocene-porphyrin-C60 triad molecule exhibited long-lived charge-separated states under visible

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• ] formed a charge-by-charge assembled structure, with alternate stacking of TATA+ and PCCp− through iπ–iπ interactions in the crystal state [20][21]. Charge-by-charge stacking assemblies of 1a+ and porphyrin-based π-electronic anions showed the crystal-state PET between proximally located anions and

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• -methylquinoline derivatives could be fluorinated in yields of up to 70%. In 2013, Groves and co-workers reported the use of manganese salen and manganese porphyrin catalysts in the preparation of a range of secondary benzyl fluorides via C–H fluorination (Figure 31) [80]. Substrates bearing electron-withdrawing

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• an aldol transformation to the final product. Bruckner and coworkers synthesized pyrrole-modified porphyrin ring systems from secochlorin bisaldehydes, representing an interesting application of the intramolecular Cannizzaro reaction. Subjecting the bisaldehyde 92 to basic conditions using Et4NOH

• Cannizzaro reaction. Microwave-assisted crossed-Cannizzaro reaction for the synthesis of 3,3-disubstituted oxindoles. Synthesis of porphyrin-based rings using the Cannizzaro reaction. Synthesis of phthalides and pestalalactone via Cannizarro–Tishchenko-type reaction. Synthesis of dibenzoheptalene bislactones

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• team introduced a manganese(III) porphyrin system as a catalyst for the BH methodology to achieve C–N coupling reactions [43]. Various tertiary amines were isolated by coupling secondary amines and benzylic alcohols using Mn7 (3 mol %) in the presence of K2CO3 (20 mol %) under reflux conditions in

• aminobenzyl alcohols and methyl ketones with Mn6 (4 mol %), NaOH (50 mol %) in toluene at 110 °C for 2 h [64]. Moderate to good yields (46–86%) of the 2-substituted quinoline derivatives were isolated (Scheme 72). In the same year, Madsen’s team introduced a manganese(III)-porphyrin catalyst for the synthesis

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• single pentafluorophenyl ring was prepared through the regioselective nucleophilic aromatic substitution reaction of the p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with 9-mercapto-m-carborane. The reaction of this porphyrin with sodium azide led to the selective substitution of

• the p-fluorine atom in the pentafluorophenyl substituent with an azide functionality which upon reduction with SnCl2 resulted in the formation of the corresponding porphyrin with an amino group. Pentafluorophenyl-substituted A3B-porphyrins were studied and transformed to thiol and amino-substituted

• carborane A3B-porphyrin were also synthesized based on the amino-substituted A3B-porphyrin. The structures of the prepared carboranylporphyrins were determined by UV–vis, IR, 1H, 19F, 11B NMR spectroscopic data and MALDI mass spectrometry. Keywords: bioconjugation; carboranes; fluorine; porphyrin; SNAr

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

• homometallic (Zn/Zn) and heterometallic (Zn/Au) compounds. In the open state, the porphyrins do not interact and the closing process allows the system to acquire distinct properties depending on the porphyrin. For the Zn/Zn system, guest binding abilities have been observed with diamines that can coordinate

• units composed of two pyridine units linked with a propyldiamine spacer (tweezers 25, see Figure 14c) have been reported by Fuzukumi and co-workers [57]. This unit has four coordination sites and can bind copper in a square planar geometry. The authors functionalized this spacer with two zinc–porphyrin

• arms. In the uncoordinated state, the conformation is not fixed so the porphyrins do not interact but when the tweezers are closed the porphyrins are facing each other and can interact. The closed and open states exhibit different electrochemical and photochemical properties. The porphyrin interaction

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

• retrocycloadditions were further exploited from bridged bicyclo[2.2.2]octadiene solubilizing fragments to generate (hetero)acenes and larger bidimensional π-CPCs such as extended porphyrin derivatives with the concomitant release of ethylene (Scheme 1, bottom left) [9][11][15]. It is important to note here that in

Catalytic multi-step domino and one-pot reactions

• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

• in the Full Research Paper by Nath and co-workers. The newly synthesized porphyrin derivatives displayed significant red-shifted absorption and emission compared to simple meso-tetraarylporphyrins [14]. The Carlone group reports an Enders-type triple cascade reaction toward cyclohexenals, using

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• ’-dicyanoquinone diimides [82], and 6,6-dicyanopentafulvenes (DCFs) [83][84] have been employed. Notably, the [2 + 2] CA–RE reaction of DMA-ethynyl-appended porphyrin with TCNQ is observed to occur on a metal surface (specifically Au(111)) under high-vacuum conditions, with successful visualization achieved

• investigated by Diederich et al. [145]. The representative molecules among these are shown in Figure 10. In 86, wherein ZnP and anilino-PCBD are linked using a spacer, the excitation of the porphyrin chromophore (at 560 nm, corresponding to the Q-band) generated an excited singlet state of ZnP (1ZnP*) with a

• , the emergence of the weak absorption band of the ZnP radical cation at 640 nm was hindered by the overwhelming absorption intensity of the residual porphyrin. The transient absorption spectra of 87 were obtained in benzonitrile solvent, which was expected to stabilize the CS state. Absorption

Substituent-controlled construction of A₄B₂-hexaphyrins and A₃B-porphyrins: a mechanistic evaluation

• Seda Cinar,
• Dilek Isik Tasgin and
• Canan Unaleroglu

Beilstein J. Org. Chem. 2023, 19, 1832–1840, doi:10.3762/bjoc.19.135

• of porphyrinogen and hexaphyrinogen forms. Keywords: A4B2-hexaphyrin; A3B-porphyrin; N-tosylimine; Cu(OTf)2 catalysis; HRESI–TOF analysis; Introduction Porphyrins and expanded porphyrins have found widespread applications in supramolecular chemistry [1][2][3][4]. Expanded porphyrins are utilized as

• -substituted N-tosylimine and 5,10-bis(pentafluorophenyl)tripyrromethane formed A6-hexaphyrin as the main product along with the inevitable formation of side products, A4-porphyrin and higher expanded porphyrins [28]. meso-Phenyloligopyrroles having electron-rich substituents at the 2-, 4-, or 6-positions were

• screened in the literature. To the best of our knowledge, hexaphyrin synthesis from the least substituted aryls appears to be not much studied. In the following study, we focused on the use of less hindered variety of precursors in hexaphyrin and porphyrin synthesis via the Cu(OTf)2-catalyzed reaction of

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

• metals. In this perspective article, the overview of both the early designs of porphyrin-crown ether hybrids, as well as the most recent advances in the synthesis and characterisation of this remarkable group of macrocyclic systems, are addressed. The discussion covers the strategies employed in

• synthesising these systems, including cyclisation reactions, self-assembly, and their remarkable reactivity. The potential applications of porphyrin-crown ether hybrids are also highlighted. Moreover, the discussion identifies the challenges associated with synthesising and characterising hybrids, outlining

• opposites, and as opposites attract, several studies were devoted to investigating the systems combining such contradictory structural elements [22][23][24][25]. In this perspective article, the subjective selection of literature demonstrating developments in the area of hybrid porphyrin-crown ether

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

• found to be capable of functionalizing specific C–H bonds to numerous functionalities, including C–F [21][22], C–N3 [23], and C–Cl bonds [24][25]. Upon these remarkable observations, methodologies involving manganese–porphyrin catalysts have been developed over the years. These methods take advantage of

• functionalization via the canonical organometallic steps of oxidative addition/reductive elimination was ruled out via catalytic reaction of the macrocyclic Groves-type porphyrin catalyst V, a species that is unable to accommodate the mutual cis-orientation of ligands for metal-centered reductive elimination. The

• 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

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• ; multicomponent synthesis; one-pot reaction; trichloroacetic acid; Introduction π-Conjugated porphyrin macrocycles are known for their applications in numerous areas ranging from oxygen transport, photosynthesis, catalysis and medicine [1][2][3]. In the past several years, diverse organic scaffolds have been

• incorporated at the porphyrin periphery and different metal ions in the porphyrin core to modulate ground-state and excited-state characteristics of easily accessible meso-tetraarylporphyrins. Some of these π-extended tetrapyrrolic macrocycles have emerged as potential candidates in photodynamic therapy and

• contruction of periphery-modified porphyrinoids [30][31][32][33][34][35][36][37][38][39][40][41], we thought to assemble benzo[f]chromeno[2,3-h]quinoxalinoporphyrins by incorporating porphyrin, quinoxaline and xanthene scaffolds in a single molecular framework using a multicomponent synthetic strategy. The

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

• . This methodology has been applied to diverse areas of chemistry, including natural product synthesis [45][46], medicinal chemistry [47][48], polymer chemistry [49][50] and porphyrin chemistry [51][52][53]. In recent years, green chemistry has become a widely used method for organic synthesis in order

• pharmaceutically active molecules, polymer synthesis, total synthesis of natural products, porphyrin functionalization, and the synthesis of various pyrrole-containing heterocyclic molecules. We believe that this review will be useful and will encourage researchers to apply the modified Clauson–Kaas reaction to

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• direction, one potential strategy is the approach followed by Feringa and co-workers [72], in which palladium-porphyrin photosensitizer-based struts were employed within a metal-organic material, allowing the use of green light as irradiation source because of the effective energy transfer between these

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• transition metal (Ni, Fe, V) porphyrin catalysts and oxygen. Catalytic reduction (H2, Pd/C) affords 2,2'-diaminobibenzyl (20) in the subsequent step [28]. 1.2 Ring-closing via amine condensation The initial synthesis of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a) was reported in 1899 by Thiele and Holzinger

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• singlet oxygen production have been identified in porphyrin-based butadiynes [7][8][9], 1,3-butadiyne-linked oligoporphycenes [10], and 1,3-butadiyne-linked amines [13]. A wide variety of applications was proposed for graphdiynes (2D allotropes of graphene), including electrocatalysts and energy devices

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• connect two diverse moieties in a single framework. Therefore, this review focuses on the synthesis and photophysical studies of β- and meso-substituted and 1,2,3-triazole-fused porphyrin conjugates. All of the porphyrin conjugates discussed here are synthesized via a copper(I)-catalyzed Huisgen 1,3

• -dipolar cycloaddition reaction between an azide and a terminal alkyne, also popular as "click reaction" or CuAAC reaction. Moreover, the 1,2,3-triazole ring also serves as a spacer and an electron transfer bridge between the porphyrin and the attached chromophores. In order to provide a critical overview

• of the synthesis and properties of various porphyrin-triazole hybrids, this review will discuss some of the key reactions involved in the preparation of triazole-linked porphyrin conjugates. Keywords: azide–alkyne; click chemistry; CuAAC; 1,3-dipolar cycloaddition; porphyrin; 1,2,3-triazole

Synthesis of meso-pyrrole-substituted corroles by condensation of 1,9-diformyldipyrromethanes with pyrrole

• Baris Temelli and
• Pinar Kapci

Beilstein J. Org. Chem. 2022, 18, 1403–1409, doi:10.3762/bjoc.18.145

• studies on porphyrins, which have many application areas such as photodynamic therapy and photovoltaic systems, have focused on oligomeric and polymeric structures in the last two decades [5][6][7][8][9]. Although such porphyrin structures have been used successfully in the development of molecular

• our knowledge, there is no generally accepted method for the synthesis of pyrrole-substituted corroles. Very recently, we reported the synthesis of porphyrin–corrole [24][25][26] and porphyrin–porphyrin dyads and triads [27] using formylated porphyrin compounds. In a continuation of research activity

• . Figure 2 shows the absorption spectrum of 2a with a strong Soret band at 412 nm and weak Q-bands at 542 and 611 nm. After the synthesis of corrole compounds, we tried to extent our studies to obtain meso-pyrrole-substituted porphyrin compounds. For this purpose, the MacDonald [2 + 2] porphyrin