Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations

• Qi-Sen Gao,
• Zheng-Wei Wei and
• Zhi-Min Chen

Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186

• intermediate Int 16 on VQM to form intermediate Int 17. As bifunctional organic catalysts, chiral ureas can synergistically activate both alkynes and selenols, thereby addressing the challenge of overcoming the increased difficulty of racemization caused by the presence of bulky SeR groups (Scheme 5). Summary

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• -involved ureas, annulation of o-arylalkynylanilines, cyclization of 2-ethynylanilines, selenocyclization of diselenides with 2-ethynylanilines as well as C–H indolization of 2-alkynylanilines with 3-functionalized indoles. Isoindolones were synthesized successfully by electrochemical annulation of

• ureas 1 proceeded smoothly in an undivided cell (reticulated vitreous carbon (RVC) anode, Pt cathode, 5 mA), forming the desired indoles 2 in high yields. The reaction showed good compatibility with various functional groups like phenyl, furyl, alkenyl and alkyl at the acetylene moieties, producing 2a–d

• functional molecules possessing five-membered rings. Electrochemical intramolecular coupling of ureas to form indoles. Electrochemical dehydrogenative annulation of alkynes with anilines. Electrochemical annulations of o-arylalkynylanilines. Electrochemical cyclization of 2-ethynylanilines. Electrochemical

Systematic pore lipophilization to enhance the efficiency of an amine-based MOF catalyst in the solvent-free Knoevenagel reaction

• Pricilla Matseketsa,
• Margret Kumbirayi Ruwimbo Pagare and
• Tendai Gadzikwa

Beilstein J. Org. Chem. 2025, 21, 1854–1863, doi:10.3762/bjoc.21.144

• pharmaceutical and agrochemical industries [38][39]. Various types of catalysts are used to enhance the efficiency and selectivity of the Knoevenagel reaction, including Lewis acids, ureas/ thioureas, amino acids, and bases such as alkali metal hydroxides, alkali metal alkoxide, amines, etc. [37][40][41][42][43

• in the rate of reaction was observed from KSU-1 < KSU-1iPr < KSU-1t-Bu < KSU-1n-Hex < KSU-1C14 (Figure 4B) even though roughly 10% of the –NH2 groups in both KSU-1n-Hex and KSU-1C14 had been converted to the less catalytically active alkyl ureas [50]. We should also point out that, despite the lower

• undergoes imine condensation with benzaldehyde. B) Mechanism in which the amine acts as a base, deprotonating malononitrile. Estimated conversions of the reactions of isocyanates with the –OH and –NH2 groups of KSU-1 to form carbamates and ureas, respectively.a Comparison of Knoevenagel catalysis results

Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins

• Juliana V. Petrova,
• Varvara T. Tkachenko,
• Victor A. Tafeenko,
• Anna S. Pestretsova,
• Vadim S. Pokrovsky,
• Maxim E. Kukushkin and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118

• '-disubstituted ureas were initially reacted with oxalyl chloride to form imidazolidinetriones 1a,b, which were then added to an iminophosphorane formed in situ from an aryl azide and triphenylphosphine. As a result of the aza-Wittig reaction, 5-iminohydantoins 2a–i were then used as dipolarophiles in the 32CA

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• base [5]. In fact, its hydrogen-bond-accepting ability is even stronger than that of the other 3-, 5- and 6-membered cyclic ethers, as well as the carbonyls of aldehydes, ketones, esters and carbonates [6][7][8]. The only better carbonyl-based hydrogen-bond acceptors are amides, carbamates and ureas [9

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• oximes 63 and N-hydroxylated ureas 64 depending on the reagent system used. Formation of oxazolidinone oximes 63 occurred using PhI(OCOCF3)2 (PIFA) as an oxidant with pyridine·HBr and the MgO additive. The oxybromocyclisation of a range of unsaturated N-alkoxyureas 62 occurred rapidly in 10 minutes at

• room temperature in acetonitrile with good yields. Formation of the N-hydroxylated ureas 64 occurred using PhI(OPiv)2 and TBABr, with MgO as an additive to trap acetic acid. Aminobromocylization of a range of unsaturated N-alkoxyureas 62 was less successful with longer reactions times up to 1 hours

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• out under a variety of conditions with cationic gold catalysts supported by phosphine ligands. The impact of ligand on gold, protecting group on nitrogen, and solvent and additive on reaction rates was determined. The most effective reactions utilized more Lewis basic ureas, and more electron

• have been masked by the high temperatures and long reaction times of early reports. For example, Widenhoefer engaged carbamates and amides in dioxane at temperatures >80 °C [12][13]. Later work showed that ureas could be engaged at room temperature when a NHC–gold catalyst system was used, outpacing

• nitrogen. Thus, the rate of intramolecular hydroamination is enhanced by a more nucleophilic nitrogen. Another qualitative interpretation is that rates are enhanced by carbonyl basicity. Gas-phase basicity measurements indicate that ureas are more basic than amides [47][50], and here the most Lewis base

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

• ], amidines [11], isothioureas [12][13], whereas thioureas [14][15], ureas [16], phosphoric acids [17][18], and squaramides [19][20] fall into the second category. The Friedel–Crafts reaction, discovered by Charles Friedel and James Crafts in 1877 allows the aromatic C–H bond functionalization through the

A versatile way for the synthesis of monomethylamines by reduction of N-substituted carbonylimidazoles with the NaBH₄/I₂ system

• Lin Chen,
• Xuan Zhou,
• Zhiyong Chen,
• Changxu Wang,
• Shunjie Wang and
• Hanbing Teng

Beilstein J. Org. Chem. 2022, 18, 1032–1039, doi:10.3762/bjoc.18.104

• attacked by a nucleophile the imidazole group readily dissociates. The N-substituted carbonylimidazoles have favorable reactivity and can be widely used in the synthesis of various valuable products such as ureas [63][64][65][66][67][68][69][70], carbamates [66][71][72][73][74], thiocarbamates [66], and

New advances in asymmetric organocatalysis

• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 240–242, doi:10.3762/bjoc.18.28

• possibilities in combination of covalent and noncovalent activation, our group designed and synthesized N-sulfinylpyrrolidine-containing ureas and thioureas and applied them in Michael additions of aldehydes to heterocycle containing nitroalkenes [25]. Dubey and Chowdhury showed that 1,4-conjugate additions of

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• )-C1 as well as N-sulfinylureas (S,R)- and (S,S)-C2 in excellent yields (Scheme 2). Application of thioureas C1 and ureas C2 in the Michael addition of aldehydes to nitroalkenes Michael addition in solution As the first benchmark transformation, we opted for the Michael addition of butanal (6a) to β

• nitroalkene 9 using catalyst (S,R)-C2. Synthesis of isothiocyanate 3a and isocyanate 3b. Synthesis of sulfinylthioureas C1 and ureas C2. Synthesis of adducts 8a,d,f in solution. Michael additions of aldehydes 6b–d with nitroalkene 9. Michael addition of 3-phenylpropanal (6c) to nitroalkene 11. Optimization of

Base-free enantioselective S_N2 alkylation of 2-oxindoles via bifunctional phase-transfer catalysis

• Mili Litvajova,
• Emiliano Sorrentino,
• Brendan Twamley and
• Stephen J. Connon

Beilstein J. Org. Chem. 2021, 17, 2287–2294, doi:10.3762/bjoc.17.146

• to the ability of squaramides to bind anionic species more strongly than ureas. The moderate enantiocontrol observed thus far prompted us to posit that the nitrogen atom on the quinoline moiety of the catalyst could participate to the deprotonation of 5a, therefore, leading to less selective

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

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

Synthesis of legonmycins A and B, C(7a)-hydroxylated bacterial pyrrolizidines

• Wilfred J. M. Lewis,
• David M. Shaw and
• Jeremy Robertson

Beilstein J. Org. Chem. 2021, 17, 334–342, doi:10.3762/bjoc.17.31

• pyrrolizidines; cyanoketones; legonmycin; vinylogous ureas; Introduction At least 40 members of the large class of pyrrolizidine alkaloids [1][2][3][4] have so far been characterized from bacterial cultures. Of these ‘bacterial pyrrolizidines’, those of the vinylogous urea type are particularly intriguing from

• vinylogous ureas, since they lack the C(1) carbonyl group, their structural relationship with bohemamine, the first genuine member of the group, qualifies them as honorary members. The structure of bohemamine, named by its discoverers at Bristol–Myers Company and Cornell University after the opera La Bohème

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

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• of amines. The latter then aminolyzed the carbamates 149 to generate ureas 151 and γ-halo-β-hydroxyalkanethiols 150. The intermediates 150 further underwent an intramolecular cyclization to produce the thietane-3-ols 145 in low to good yields [58] (Scheme 30). Paclitaxel (Taxol®) and docetaxel

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

• good yields of 145h–l (Scheme 32). Additionally, products derived from ureas (i.e., 146), N,N-dimethylaniline (i.e., 147), amides (i.e., 148), and lactams (i.e., 149a) were obtained. Moreover, for N-methylpyrrolidinone, α-arylation was achieved in a good yield and regioselectivity for the substitution

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• liquid crystal design [10][11]. N,N′-Bis(3,4,5-trialkoxylphenyl)ureas were identified as columnar liquid crystalline compounds presenting ferroelectric properties [12]. Another study reported cyclic disubstituted ureas with liquid crystalline ferroelectric and antiferroelectric phases [13]. Relating to

• the thiourea moiety, there is only one recent report, in which some derivatives of N-benzoyl-N’-arylthiourea with liquid crystalline properties have been investigated [14]. One aspect that compounds forming hydrogen bonds, such as ureas, thioureas, amides etc. for the use in electronic devices is the

• the thiocyanate salt, following the same experimental protocol. However, when a cyanate salt was used, only the amides 19–22 were isolated as the main products. The target ureas were not obtained, according to Scheme 3, part A. To test the hypothesis of intermediate formation of acyl cation [ArCO

Small anion-assisted electrochemical potential splitting in a new series of bistriarylamine derivatives: organic mixed valency across a urea bridge and zwitterionization

• Keishiro Tahara,
• Tetsufumi Nakakita,
• Alyona A. Starikova,
• Takashi Ikeda,
• Masaaki Abe and
• Jun-ichi Kikuchi

Beilstein J. Org. Chem. 2019, 15, 2277–2286, doi:10.3762/bjoc.15.220

• were investigated to realize electrochemically controlled H-bonding [23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Especially, oxidation-active ureas are an important class of such compounds [25][26]. In the neutral state, ureas can provide two NH protons for multiple H-bonding, as often

• ][34][35][36][37][38][39][40]. In contrast to the vast majority of oxidation-active ureas, those having two redox centers at both ends have not received attention except for 1,3-bis(ferrocenyl)urea FcFc [41][42], a cyclometalated diruthenium complex [43], and bis(NAr3) counterparts, including 1a

• substituents R at the para-position of the benzene adjacent to the nitrogen centers were synthesized to tune the oxidation potential of the nitrogen centers (Figure 1). According to a previously reported method for the synthesis of ureas [45], symmetric ureas 1 were synthesized from the corresponding amines

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Bambusuril analogs based on alternating glycoluril and xylylene units

• Tomáš Lízal and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2019, 15, 1268–1274, doi:10.3762/bjoc.15.124

• urea groups can participate in intermolecular hydrogen bonding resulting in the formation of tubular [5][6][7] or gel-like [8] structures. Ureas lacking of N–H hydrogen atoms such as ethyleneureas, glycolurils, and biotin are also important building blocks of macrocyclic receptors such as cucurbiturils

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• , etc. The urea component has the main structural restrictions, since monosubstituted alkyl ureas work well but thioureas have provided much lower yields. Wang et al. produced a library of steroidal [17,16-d]pyrimidine derivatives such as 40 employing a particular extension of the Biginelli reaction

A three-component, Zn(OTf)₂-mediated entry into trisubstituted 2-aminoimidazoles

• Alexei Lukin,
• Anna Bakholdina,
• Anna Kryukova,
• Alexander Sapegin and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2019, 15, 1061–1064, doi:10.3762/bjoc.15.103

• possibility to incorporate of an external primary amine into the cyclization process, which would lead to trisubstituted 2-aminoimidazoles 5 has not been explored (Figure 1). 2-Aminoimidazoles have a remarkably broad utility in medicinal chemistry [7]. Moreover, ureas 4 can, in principle, be generated in situ

• preparation of ureas 4 could, in principle, enable a three-component entry to imidazoles 5 (an attractive option from the standpoint of library array synthesis), we compared the isolated yield of the above reaction (with the ready-made urea 4a) with the yield obtained in the three-component format. To our

• synthesis of trisubstituted 2-aminoimidazoles. This is the first example illustrating the utility of such ureas in the synthesis of imidazoles as previously reported syntheses only involved base-promoted cyclization into 2-imidazolones. The reaction can be conveniently conducted in a three-component format

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• ], (thio)ureas [30][31] and phosphoric acid derivatives [27]. Cyclodiphosph(V)azanes [32][33][34][35] and silanediols [1][28][36] are two new hydrogen bonding scaffolds for anion recognition [37] and ion-pair catalysis [6][38]. Since Kondo et al. established silanediol 1 [39] as HBD for anion recognition