Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• except the preparation of the aminoaniline building block tert-butyl (2-amino-5-bromophenyl)carbamate (5), which was prepared by Boc-protection of the 5-bromo-2-nitroaniline (6) and subsequent reduction of the nitro group (see Supporting Information File 1, section II.1). Cross-coupling reactions Stille

• halogenated N-acetyl diazocines according to the procedure of Maier et al. [34] with tert-butyl carbamate resulted in the formation of Boc-protected amino-substituted N-acetyl diazocine 19 in a yield of 72%. However, the reaction only took place if iodo N-acetyl diazocine 3 was used as starting material

• . Using diphenylamine as a more electron-rich amine resulted in the formation of diphenylamino-substituted N-acetyl diazocine 20 in a significantly lower yield of 25% starting from the bromide 2 and 47% starting from the iodo precursor 3 (Table 5). Deprotection of carbamate 19 with trifluoroacetic acid

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• by displacement of the mesyl group to give a six-membered cyclic carbamate, a reactivity that has been described earlier [34]. Thus, care was taken to quickly isolate compound 14 and use it immediately in the next step. Deblocking of the secondary amine by treatment with trifluoroacetic acid afforded

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• -2 position of glycosyl donors which can contribute towards 1,2-trans glycosylations without affecting the reactivity of the donor. They introduced carbamate ester moieties as alternative protecting groups. The N-phenylcarbamoyl (PhCar) moiety showed high stability in the pH range of 1–12 and it

• ) which not only showed higher yield (78%) but also a significantly higher anomeric stereoselectivity. With the aim to understand the participating role of the C-2 protecting ‘carbamate moiety’ Liang et al. introduced the N-benzylcarbamoyl moiety as the protecting group for the C-2 position [134]. They

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• counteranion. The use of a carbamate among the substrates instead of the amine allowed the synthesis of propargylcarbamates 11. This reaction, effective only for the aromatic aldehydes, did not require other co-catalysts or ligands (Scheme 8) [21]. Three-component reactions of alkynes, alkyltrifluoroborates

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• carbamate group by interaction with the oxygen atom of the phosphoryl group. Although recently Rana and co-workers published a review article covering catalytic asymmetric transformations of azadienes [16], there is still room for this review which only focuses on non-covalent organocatalyzed cyclizations

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• 19F,1H NOE experiments of compound 8f did not show any specific correlation between fluorine atoms and the protons of the amino acids (see Supporting Information File 1). Finally, the low chemical shifts of the amide and carbamate protons (6.4 ppm for NH of valine and 5.5 ppm for the NH of

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

• 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

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• stereospecific synthesis of γ- and γ,δ-substituted homoallylic amines by a three-component reaction between an aryl acetal, BocNH2 carbamate and a 2,3-disubstituted allylsilane, in presence of the triflate-assisted bifunctional HBD/πAr-Ar catalyst [39]. Catalytic cycle for the three-component allylation with HBD

Hypervalent iodine-catalyzed amide and alkene coupling enabled by lithium salt activation

• Akanksha Chhikara,
• Fan Wu,
• Navdeep Kaur,
• Prabagar Baskaran,
• Alex M. Nguyen,
• Zhichang Yin,
• Anthony H. Pham and
• Wei Li

Beilstein J. Org. Chem. 2024, 20, 1405–1411, doi:10.3762/bjoc.20.122

• , which then partitions into an ion pair suitable for olefin activation, followed by the addition of the bifunctional anionic carbamate (Scheme 1c). Our hypothesis here aims to directly access the reactivity of the cationic hypervalent iodine catalyst through an initial activation first, which we reason

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

• Cannizzaro reaction commencing from 68. The primary hydroxymethyl functionality in 69 was oxidized to the corresponding aldehyde 70, which was subsequently treated with 37% aqueous formaldehyde and NaOH, to result in a mixture of the gem-hydroxymethyl derivative 72 and the carbamate 71 which led to the spiro

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• radical intermediate 68. This carbon-centered radical, positioned near three heteroatoms, undergoes rapid β-cleavage to produce a carbamate 69 and a deoxygenated alkyl radical 70. The formation of carbamate byproduct 69, having a strong C=O double bond, acts as thermodynamic driving factor for the C–O

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

• correlation of faster rate with more electron-withdrawing ligand. Experiments with other substrates display consistent results (further discussion below, Table 6, catalyst 4a reacts faster than 4c in the reaction of carbamate 1b → 3b). Solvent effect For a screen of solvent effect on the rate of 1a

• amounts of water (Table 3, entries 12–14) [39]. The same decelerating effect of water in MeOH solvent was seen with [JPhosAu(NCCH3)]SbF6 (5) (Table 3, entries 15–17). Substrate effect The rate of hydroamination to cyclized 3a–c was measured for three substrates, tert-butylurea 1a, tert-butyl carbamate 1b

• , and benzamide 1c (Table 4). Under standard conditions (2.5 mol % [JPhosAu(NCCH3)]SbF6, 0.05 M alkene in DCM) benzamide and carbamate hydroamination were too slow to measure, so the reactions were done with 55 μL MeOH promoter but still only an estimated rate constant was obtained for 1c (14

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• hydroamination reaction products via a proton-coupled electron transfer (PCET) mechanism. Cyclic voltammetry (CV) analysis indicated that the chemoselectivity was derived from the size of the hydrogen bond complex, which consisted of the carbamate substrate and phosphate base, and could be controlled using

• presence of methyl vinyl ketone (MVK) as a radical acceptor (Table 1). Tetrabutylammonium dibutyl phosphate (phosphate base), which operates as a PCET initiator through hydrogen bond formation with the N–H bond of amide/carbamate [11], was used as an additive. As a result, N-alkylated product 3 was

• of conjugate addition of a cathodically generated carbamate anion was ruled out, prompting us to consider that N-alkylation proceeded via a radical mechanism. On the other hand, the addition of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) led to the predominant formation of cyclized dimer 4 without N

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• the robustness of this method. Substrates with multiple electron-withdrawing substituents such as trifluoromethyl and bromide gave good yields. The ethyl carbamate 2q proved to be a valid substrate for the reaction with a 74% yield. Phenylacetamide as the substrate resulted in the formation of 2r in

Synthesis of 7-azabicyclo[4.3.1]decane ring systems from tricarbonyl(tropone)iron via intramolecular Heck reactions

• Aaron H. Shoemaker,
• Elizabeth A. Foker,
• Elena P. Uttaro,
• Sarah K. Beitel and
• Daniel R. Griffith

Beilstein J. Org. Chem. 2023, 19, 1615–1619, doi:10.3762/bjoc.19.118

• cleanly according to TLC analysis, but the isolated yield of the intramolecular Heck product was low, perhaps due to instability of one of the intermediate palladium complexes and/or a slow olefin insertion step. Moreover, the product was obtained as an inseparable mixture of the allylic carbamate 18 and

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• of glycerol is readily hydrolyzed in vivo and in serum [100][101]. With the aim to produce more stable compounds, the modification of the sn-2 position of the glycerol was reported. A first option consisted in placing a carbamate function leading to the synthesis of methyl carbamoyl-PAF (1-O

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

• hydroarylation of tert-butyl vinylcarbamate and unactivated alkenes like 1-octene and 3-buten-1-ol although the vinyl carbamate substrate (Epred = −2.2 V vs SCE) is significantly easier to reduce than most aryl chlorides. This selectivity, especially considering the need for an excess of the vinyl carbamate

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

• of the etheric oxygen atom and the antibonding orbital of the P=O bond (the stereoelectronic effect), leading to the more stable anti-diastereomer 74 (Scheme 16) [38]. In the phostone 74 was installed a linker 2-(5-aminopentoxy) group via transesterification with benzyl N-(5-hydroxypentyl)carbamate

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• the reaction with tert-butyl-N-allyl carbamate 7g (1:6) while the reaction with allylcyclohexane resulted with the lowest yield (7f, 28%), probably due to the steric hindrance of the reagents. In the case of N-Boc-allylamine, improved diastereoselectivity might result from the coordination of the

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

• ]-sigmatropic rearrangement of the diazabicycle 47 to form the allylic carbazate intermediate 51. Nucleophilic attack of an organomagnesium, or organocuprate, in an anti SN2’ fashion on 52 furnish the final ring-opened product 49. The authors note the use of a carbamate protecting group was crucial for the

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• underwent undesired ring openings. Treating 12 with BocNH2 resulted in the formation of protected guanidine 15 in 80% yield (Scheme 2c), which would not be possible to obtain via an oxidative cyclization of the corresponding iodine(I) species due to a carbamate cleavage with acid. The other dicationic salts

Synthesis, α-mannosidase inhibition studies and molecular modeling of 1,4-imino-ᴅ-lyxitols and their C-5-altered N-arylalkyl derivatives

• Martin Kalník,
• Sergej Šesták,
• Juraj Kóňa,
• Maroš Bella and
• Monika Poláková

Beilstein J. Org. Chem. 2023, 19, 282–293, doi:10.3762/bjoc.19.24

• inverted via cyclic carbamate 21. Aminoalcohol 22 obtained after a basic hydrolysis of 21 was N-alkylated with the corresponding arylalkyl bromides to furnish derivatives 23–25. These were subjected to an acidic hydrolysis of the acetonide moiety to give the target compounds 26–28. Iminosugar 29 (6-deoxy

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• group where an immobilized lipase (e.g., CALB) facilitated the derivatization of high-boiling benzyl alcohol in scaled Curtius rearrangement reactions. Ultimately, this approach negated the use of column chromatography in favor of a simple trituration process to isolate pure carbamate products [106

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• somewhat, giving us a 41% yield after 12 h of the reaction. Testing the same conditions for dimer 5, we also noticed a speed up in the reaction rate, but a presence of the trimer with an extra CD moiety connected by carbamate group (Mr ≈ 4000) was spotted, giving us lower yields. We assume the Lewis acid

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• and carbamate groups form inclusion complexes with water or methanol (Figure 3a–d). In the crystal state, a common hydrogen-bonded motif is observed, in which the guest molecule is located in a pocket created by amide/carbamate groups and the triazinane ring of the 3N-TAAD structure that is well

• –178.1°) forming two -cyclic motifs. There seems to be a preference for the coordination of certain guest molecules depending on the nature of the amide/carbamate groups. Thus, N-propionyl and ethyl carbamate derivatives (4a, 4a·HCl, and 4b) form the aforementioned complexes with water (Figure 3c

• , 21, and 21·HCl as well as the previously described 3O-TAADs 2 do not form such host–guest complexes, although water and methanol molecules are present in their crystal lattices. Thus, the presence of amide/carbamate groups is essential for the assembly of these supramolecular structures. The