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

• ][48][49][50]: 1) CuII → CuI → CuII; 2) CuI → CuIII → CuI; 3) CuII → CuIII → CuI → CuII. In 2006, Li et al. demonstrated that the CDC reaction of the C(sp3)–H bond of malonate diesters or other active methylene compounds with the C(sp3)–H bond adjacent to the oxygen atom of cyclic and open-chain

• oxidative alkylation of cyclic benzyl ethers with malonates or ketones. Oxygen is used as a terminal oxidant at atmospheric pressure. The key intermediate of this oxidative coupling reaction is benzyl alcohol intermediate C (Scheme 4) [52]. The generation of N–O radicals from NHPI in the presence of oxygen

• triggers the whole coupling reaction. The potential application of NHIP as a catalyst for oxidative coupling reactions with oxygen as a terminal oxidant was explored. In 2011, Garcia-Mancheño et al. developed a Cu-catalyzed CDC of cyclic benzyl ethers 10 with aliphatic or α,β-unsaturated aldehydes 13 or 14

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• Toulouse, France University of Tunis El Manar, Laboratory of Organic Chemistry, Faculty of Sciences, Campus, 2092 Tunis, Tunisia 10.3762/bjoc.19.93 Abstract A highly α-regioselective N-nucleophilic allylic substitution of cyclic MBH alcohols and acetates with imidazole or benzimidazole, in toluene at

• , such alcohols were in situ converted into the corresponding O-allyl carbamates as leaving groups, followed by their reaction with imidazoles, affording the SN2’ products 3 (Scheme 1, reaction 1, iii). Correlatively, we have previously reported a direct amination of cyclic MBH alcohols 4 with morpholine

• that nucleophilic allylic substitution reactions of acyclic/cyclic MBH adducts 1, 4, or 5, bearing good or poor leaving groups, using imidazole derivatives as nucleophilic reagents, have not been extensively developed. Therefore, in continuation of our previous study on the nucleophilic allylic

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• to explain the formation of different cyclic compounds, a plausible reaction mechanism was proposed in Scheme 2 on the basis of the present experiments and the previous works [51][52][53]. Firstly, 3-isatyl-1,4-dicarbonyl compound 1 was converted to a carbanion in the presence of base. In the

• , the nucleophilic addition of the amino anion to the carbonyl group in the of 1,3-cyclohexanedione scaffold resulted in cyclic intermediate C. Thirdly, the elimination of water from intermediate C gave the isolated product 3. In the case of the intermediate B2 with a benzoyl group, there are two kinds

• of reactive carbonyl groups in intermediate B2, one carbonyl group is in the benzoyl moiety and another carbonyl group is in the 1,3-cyclohexanedione part. In this case the amino group selectively attacked the benzoyl group to give cyclic intermediate D, while the two carbonyl groups in the 1,3

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

• , including terminal aliphatic alkenes, internal (cyclic) styrenes, and one example of a nonconjugated diene, suggesting RLT to be compatible with many functionalities. The diastereoselectivity of the reaction varies, with high anti-selectivity being achieved with cyclic styrenes and low diastereoselectivity

• intermediate. RLT to this radical from another azide ligand leads to a diazidated product. The overall scope of both reports suggests that the diazidation of simple to complex drugs/natural product-derived alkene substrates is readily achievable, including highly substituted and cyclic aliphatic alkenes

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

• energy orbitals on photooxidized or photoexcited photosensitizers with more positive potentials. Cyclic voltammetry can be used to measure ground-state redox potentials by varying the potential at a working electrode with respect to a reference electrode and measuring the current response [19]. In

• photocatalysis. Cyclic voltammetry carried out in standard conditions for mimicking an acetonitrile system had not been close enough to the catalytic conditions to get the required redox potentials. The difference between the oxidation potential of a sacrificial donor and the reduction potential of the excited

• -workers published a study in which they used a cyclic tertiary amine sacrificial donor that they had designed to be regenerated [32]. This was significant because instead of replacing amine sacrificial donors with redox mediators, this paper proposed an alternate strategy of an ex-situ regeneration of

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• being slightly different (0.18 e and 0.19 e) due to its non-planarity, whereas the cyclic, planar variant’s potentials were each 0.20 e [88][89]. The strength of the σ-holes for I-8 and I-9 were far greater than those of other HVI reagents, which was unsurprising given that its iodine atom was

• potentials of 0.075 e and 0.048 e. The cyclic dimedone-derived ylide I-12 showed similar potentials of 0.080 e and 0.052 e, as did the Meldrum’s acid-derived ylide I-13 (0.085 e and 0.057 e). Whether the ylide was cyclic or acyclic, the σ-hole opposite the β-dicarbonyl motif was consistently greater in

• had occurred, which was attributed to halogen bond complex formation. In 2019, the Murphy group reported the first transformation induced by blue LED irradiation of cyclic and acyclic iodonium ylides (e.g., 6) and alkenes, which generated cyclopropanes 40 in yields up to 96% (Scheme 8) [125]. UV–vis

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

• . Notably, carbonylative amidation of a borylated aryl bromide to 26d proceeded well, where a Pd-catalyzed carbonylative amidation reaction would be plagued by undesired Suzuki coupling. Several secondary cyclic and acyclic amines, as well as primary amines were successfully employed as amine coupling

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• , 130.6, 130.4, 130.3, 123.8, 123.6, 123.1, 116.8, 116.7, 116.5; HRMS–MALDI (m/z): [M + H]+ calcd for C30H17FN2O3S, 505.0944; found, 505.0973. Electrochemical studies The cyclic voltammetry curves were recorded with a CHI610D electrochemical workstation (CHI instruments, Inc., Shanghai, China) in N2

• ) NI-PTZ-Ph-O (λem = 440 nm, c = 2.0 × 10−5 M) in different atmospheres (N2, air). Excited with a picosecond pulsed laser (λex = 340 nm), in HEX, 20 °C. Cyclic voltammograms of the compounds. (a) NI-PTZ-F; NI-PTZ-Ph; NI-PTZ-CH3; NI-PTZ-OCH3; NI-PTZ-C5 in deaerated DCM and (b) NI-PTZ-F-O; NI-PTZ-Ph-O

• ; NI-PTZ-C5-O in deaerated ACN. Ferrocene (Fc) was used as internal reference (set as 0 V in the cyclic voltammograms), 0.10 M Bu4NPF6 as supporting electrolyte, scan rates: 100 mV/s, c = 1.0 × 10−3 M, 20 °C. Thermogravimetric analysis curves of NI-PTZ-F, NI-PTZ-Ph, NI-PTZ-CH3, NI-PTZ-OCH3, NI-PTZ-F-O

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• from industrial processes, power generation, and transportation contribute significantly to global warming and climate change. Carbon capture and storage (CCS) technologies are essential to reduce these emissions and mitigate the effects of climate change. Cyclodextrins (CDs), cyclic oligosaccharides

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• ) as a product with 59% yield. Similarly, the reaction of cyclic secondary amines also resulted in arylation under the optimal reaction conditions to give products 3s–v with 42–48% yields. The treatment of indoline with iodonium ylide 2b in the presence of 10 mol % of CuSO4·5H2O affords product 3w in

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

• Xiu-Yu Chen,
• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• -configured. For explaining the formation of the various cyclic compounds, a plausible reaction mechanism was proposed on the base of the previously reported works [41][42][43][44] and the present experiments (Scheme 2). Initially, the nucleophilic addition of isoquinoline to dimethyl acetylenedicarboxylate

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• aza-Friedel–Crafts process between indoles 4 and cyclic N-sulfonyl ketimines 5. The authors employed the BINOL-based chiral phosphoric acid P2 bearing two imidazoline moieties at the ortho-positions as the catalyst which activates both reactants through H-bonding where the NH group of the nucleophile

• than with indoles (Scheme 3) [26]. In 2018, Kim and co-workers developed an aza-Friedel–Crafts protocol involving pyrroles 9 as the π-nucleophile in combination with cyclic N-sulfimines 12. The chiral phosphoric acid P4 was used to catalyze the introduction of a pyrrole-substituted aza-quaternary

• stereocenter in cyclic sulfamidate derivatives. N-Alkyl and N-benzyl-substituted pyrroles responded to the process with appreciable enantioefficiency. However, pyrrole was not proved to be the efficient substrate in terms of stereocontrol [27] (Scheme 4a). In the very next year, pyrrole was successfully

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• ], the cyclic guanidine alkaloid massinidine [17], and the siderophore massiliachelin [18]. An antiSMASH analysis [19] of the genome of Massilia sp. NR 4-1 revealed the presence of additional biosynthetic gene clusters, including another putative metallophore gene cluster (ACZ75_RS05545–ACZ75_RS06020

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• ], Liu [35], and Yang [36] achieved similar transformations through visible-light photocatalysis. In addition, Guo [37][38] improved the protocol by using low-cost nickel and iron catalysts. However, most of these advancements mainly relied on the excellent redox potential manipulation of cyclic oxime

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• 3b used in only three cases [12][13][19], to the best of our knowledge. Extending beyond Scheme 2, only two syntheses of nitrocyclopropanes containing cyclic keto esters or diketones have been reported [20][21]. These findings indicate that the synthesis of nitrocyclopropanes with an acyl group is

• occurs, leading to five-membered cyclic nitronates [23]. To the contrary, such reaction was not observed at all, which is presumably due to the lower electron-donating ability of the benzene ring. The other adducts 4c–g were subjected to the cyclization under the same conditions (Table 3). When the

• acyl group are unknown, except for a derivative of cyclic diketone [20][21]. Although diacetyl derivative 13 has been reported in some studies [12][13][19], we corrected its structure to dihydrofuran 8. This is the first report of the synthesis of acylated nitrocyclopropanes 1. After the conjugate

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• earlier experience, we employed the tropylium ion with the more lipophilic bis(trifluoromethane)sulfinimide (NTf2) anion because of its better solubility in the applied organic solvents than the commercially available tetrafluoroborate (BF4) form [22][23][24]. The cyclic urea DMEU (1,3-dimethyl-2

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

• Photoresponsive rotaxane discrete crystals A complete understanding of the crystallization mechanisms accompanied by a rational design can lead to the obtention of crystalline molecular materials which allow the dynamics of the counterparts to take place [35][36][37]. Indeed, the motion of the cyclic counterparts

• pseudorotaxanes, the supramolecular interactions between the counterparts are retained, thus constituting stable intertwined species showing analogous properties to those of rotaxanes. The pseudorotaxanes 1 were constituted by a dibenzo-24-crown-8 cyclic component and an ammonium-based thread functionalized with

• UMUMOF-(E)-3 due to the decrease of the number of hydrogen bonds interactions between the counterparts, as determined by solid-state 2H NMR. Interestingly, UMUMOF-(E)-3 was employed as a molecular nanodispenser of para-benzoquinone working through a cyclic operation mode which involved three steps

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• starting from both cyclic and acyclic alkyl bromides. The findings of the reaction’s stereochemistry and observations made during some cyclization or ring-opening reactions indicated that the C–H alkylation may proceed through a radical-type mechanism. Next, in 2013, Wang and co-workers [52] reported a

• . Subsequently, insertion of alkene 68 provides the cyclic Pd(II) intermediate 72 which undergoes β-hydride elimination to produce the desired product 69. In the same year, Ramana and Goriya [75] proposed an unexpected C-6 (C-2)-propenylation reaction of pyridine in the presence of allyl bromide (73) and a Ru

• results in the five-membered rhodacycle 184 which is followed by a second regioselective insertion of alkyne 179 into the Rh–C bond of 184 providing the seven-membered cyclic intermediate 185. Further reductive elimination furnishes the quinoline product 180 and a Rh(I) species, with the latter being

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• behavior was observed with substrate 4b, where a mixture of thiazole 13, sulfide 14b and thiobenzamide was formed in DMF (Table 3, entries 9 and 10) even without any base. This behavior corresponds to a much worse leaving ability of methylamine (pKa = 10.6) from cyclic intermediate en route to thiazole 13

• acidifying effect as compared to C(CH3)2) and the effect of ring strain [35][36] (C–H in the 5-membered α-thioiminium salt 15 is more acidic than in the 6-membered salts 6a,b or non-cyclic salts 12b). The subsequent formation of the thiirane ring through TS2 (which is strongly entropically favored although

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• , is certainly not surprising since both electronic and steric factors favor attack on the convex face of the pyramidalized double-bond. Electrophilic bromine can attack the double bond in 1 mainly from exo-face of the double bond to form the cyclic bromonium ions 10. The major products, 2, 3, 4, and 5

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• bond formation through RCM reaction: Ring-closing metathesis (RCM) is an efficient strategy for the construction of common to large cyclic compounds via the formation of a C=C bond [26], which can be further reduced to a C–C bond. To prepare phostam-derived antitumor agents, ethyl N-allyl-N-(but-3-en-1

• -hexahydro-1,2-oxaphosphecine 2-oxide 26 in 70% yield. After the Pd-catalyzed hydrogenolysis, it was transformed to both cyclic ten-membered phostone 2-(4-methylphenyl)benzothiophene-fused 2-hydroxy-1,2-oxaphosphecane 2-oxide (27) in 40% yield and acyclic (4-(3-methyl-2-(4-methylphenyl)benzo[b]thiophen-4-yl

• –elimination. Both they are potential chiral phosphorus ligands (Scheme 20) [25]. When Fuchs and co-workers investigated the conversion of cyclic vinyl sulfones to vinylphosphonates, they found that the reaction of (1S,2R)-2-methyl-3-(phenylsulfonyl)cyclohept-3-en-1-ol (100) and diethyl phosphonate generated

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

• -conjugation of 1,8-bis(dimethylamino)naphthalene (DMAN) fragments through a butadiyne linker and a donor–acceptor aryl–C≡C–DMAN conjugation path. The conjugation path can be “switched” simply by protonation of DMAN fragments. X-ray diffraction, UV–vis spectroscopy and cyclic voltammetry are applied to analyze

• us to undertake the current study. X-ray crystallography, UV–vis spectroscopy and cyclic voltammetry were applied to analyze the extent of π-electron conjugation and the efficiency of the particular donor–acceptor conjugation path in chromophores 5. Results and Discussion Synthesis The target

• to its analogs with electron-withdrawing substituents. The redox properties of oligomers 5 were evaluated by cyclic voltammetry (CV) in dichloromethane solution containing 0.1 M n-Bu4NPF6 in the standard three-electrode electrochemical cell: glassy carbon working electrode, platinum auxiliary

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• enolate. González-Gómez et al. studied the tandem conjugate addition of dialkylzincs to cyclic enones (9, 12) and the subsequent reaction of the enolate with N-tert-butanesulfinylimines 10 (Scheme 4) [24][25][26]. Their method was applied to a broad range of substrates (5–7-membered rings) with equally

• using acyclic enones 14 [27]. Their tandem conjugate addition/Mannich reaction methodology offers access to various non-cyclic β-aminoketones 16 with multiple contiguous stereocenters in high diastereo- and enantioselectivity (Scheme 5a). Additionally, chiral isoindolinones 18 and 2,3,4-trisubstituted

• imines or their synthetic equivalents. Furthermore, we wanted to develop an enantioselective and diastereoselective process without adding chirality elements within the reagents. For our initial studies, we have selected the well-studied cyclic enones as substrates and the Taniaphos ligand (L14) that has

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• employing chiral auxiliaries [4][5] and asymmetric phase-transfer catalysis [6][7]. The former approach is commonly based on the application of chiral derivatives of glycine containing structurally diverse chiral auxiliaries, both cyclic [8][9][10][11] and acyclic [12][13]. Transition-metal complexes

• complexes. Electrochemical properties For further applications of the (GlyNi)L7 and (ΔAlaNi)L7 complexes in electrochemically activated functionalization of amino acid fragments, a more detailed electrochemical study is an important precondition. Electrochemical properties were investigated using cyclic

• cyclic voltammetry time scale. The spin density in the radical anion is mainly localized on the Ni d-orbitals and on the N and O atoms of its coordination environment (see Supporting Information File 1). The reduction of the complex (ΔAlaNi)L7 is irreversible at scan rates lower 2000 mV/s. Full

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• sketched in red, with newly formed cyclic structures being highlighted. Review Earth-abundant metals Among the transition metal used in organic synthesis, the late transition metals like rhodium, palladium, and iridium have taken center stage when it comes to methodology development. Although these late