Search results

Search for "alkene" in Full Text gives 520 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

  • Chun-Yu Mi,
  • Jia-Yuan Zhai and
  • Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

Graphical Abstract
  • first report by Stork in the 1950s [1][2][3]. Compared with enols, enamines benefit from the lone pair of electrons on the nitrogen atom, which enhances the nucleophilicity of the alkene, enabling it to react with a broad range of electrophiles. This activation mode of carbonyl compounds has been so
  • , the terminal alkene remains intact during this process, and the initial protonation proceeds with full stereocontrol, rendering this transformation both highly chemo- and diastereoselective. From the cyclization result, it is presumed that the higher nucleophilicity of the alkyne functionality over
  • the terminal alkene and the conformational strain of forming a bridge[3.2.1]bicycle might be responsible for a selective 6-exo-trig cyclization. From tricyclic compound 4, anti-Markovnikov oxidation catalyzed by palladium led to the formation of aldehyde 5. When treated with p-TsOH, the intramolecular
PDF
Album
Review
Published 22 May 2025

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

  • Shyam Sathyamoorthi,
  • Appasaheb K. Nirpal,
  • Dnyaneshwar A. Gorve and
  • Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

Graphical Abstract
  • Abstract We present the first examples of alkene amino-sulfonoxylation reactions that leverage the unique reactivity of carbamate tethered N-alkoxy nitrenium ions. In almost all cases examined, the reactions deliver product with exquisite regioselectivity and diastereoselectivity. The protocols followed
  • are operationally very simple and only use commercial I(III) reagents and sulfonic acids, amounting to a metal-free protocol for alkene amino-oxygenation. No special precautions need be taken to exclude air or ambient moisture, and the products are amenable to further transformations. Keywords
  • : alkene; amino-sulfonoxylation; metal-free; tethered nitrenium; Introduction Our laboratory has a programmatic focus on the development of metal-free oxidation reactions that avoid the use of toxic reagents such as osmium and chromium [1][2][3]. In line with this agenda, we recently explored a mild amino
PDF
Album
Supp Info
Full Research Paper
Published 19 May 2025

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

  • Zhiyang Zhang,
  • Jialei Hu,
  • Hanfeng Ding,
  • Li Zhang and
  • Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

Graphical Abstract
  • at C10 was then introduced via a Michael addition (MeMgBr, CuI) to afford 22 in a yield of 65% (4:1 dr at C10). Initial attempts on the carbonyl 1,2-transposition protocol reported by Dong and co-workers were ineffective [45], leading to premature hydride termination and the formation of alkene 23
  • . As an alternative solution, by treating 22 with KHMDS and PhNTf2, enol triflation took place successfully. The resultant triflate was coupled with n-Bu3SnH to afford Δ1,29-alkene 23 in 83% yield over two steps. Subsequent hydroboration–oxidation by employing BH3·THF proceeded smoothly, providing a
PDF
Album
Supp Info
Full Research Paper
Published 12 May 2025

Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines

  • Muhammad Hasan,
  • Anatoly A. Peshkov,
  • Syed Anis Ali Shah,
  • Andrey Belyaev,
  • Chang-Keun Lim,
  • Shunyi Wang and
  • Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74

Graphical Abstract
  • scaffolds (Scheme 6) [64][65]. First, we attempted heterogeneous hydrogenation of the alkene functionality in compound 16a under 1 atm hydrogen pressure using Pd/C as a catalyst. Although the reaction proved sluggish, we were able to drive it to completion over a prolonged reaction time of 14 days
PDF
Album
Supp Info
Full Research Paper
Published 08 May 2025

Recent advances in controllable/divergent synthesis

  • Jilei Cao,
  • Leiyang Bai and
  • Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

Graphical Abstract
  • , the Shu group developed a catalyst-controlled regioselective and enantioselective hydroamination reaction of electron-deficient alkenes (Scheme 7) [30]. By efficiently regulating the regioselectivity and enantioselectivity of alkene 23 hydrometallation through catalytic systems, they overcame the
  • C(sp3)–C(sp3) coupling via distal stereocontrol, efficiently producing C3-alkylated pyrrolidines, while the nickel catalytic system afforded C2-alkylated pyrrolidines through a tandem alkene isomerization/hydroalkylation process. This method utilized readily accessible catalysts, chiral BOX ligands
  • insertion to achieve C3 selectivity, whereas nickel catalysis involved alkene isomerization to generate a (2,3-dihydropyrrolyl) intermediate Int-35, followed by C2-selective coupling. In 2024, the Zheng group reported a catalyst-controlled cyclization reaction of bicyclo[1.1.0]butanes (BCBs) 32 with α
PDF
Album
Review
Published 07 May 2025

Light-enabled intramolecular [2 + 2] cycloaddition via photoactivation of simple alkenylboronic esters

  • Lewis McGhie,
  • Hannah M. Kortman,
  • Jenna Rumpf,
  • Peter H. Seeberger and
  • John J. Molloy

Beilstein J. Org. Chem. 2025, 21, 854–863, doi:10.3762/bjoc.21.69

Graphical Abstract
  • energy sensitizers, would represent an attractive platform for future reaction design. Here, we disclose the photoactivation of simple alkenylboronic esters established using alkene scrambling as a rapid reaction probe to identify a suitable catalyst and boron motif. Cyclic voltammetry, UV–vis analysis
  • facilitated landmark organic transformations, such as the venerable Paternò–Büchi [6][7][8], Norrish–Yang [9][10][11], and enone–alkene cycloadditions [12][13][14], that proceed via the generation of a singlet or triplet diradical through the activation of an unsaturated bond [2][14]. While these seminal
  • contributions have enabled the efficient activation of carbonyl and alkene moieties, the inability of most organic molecules to efficiently absorb photons at longer wavelengths often preclude their use in direct excitation strategies, requiring unique experimental set ups and light sources that are
PDF
Album
Supp Info
Letter
Published 30 Apr 2025

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

  • Seeun Lim,
  • Teresa Kim and
  • Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

Graphical Abstract
  • % yield under basic conditions using sodium hydroxide and tert-butanol. The reduction of nitrile 3q with lithium aluminum hydride generated amine 7 in an 85% yield, whereas the selective hydrogenation of the alkene moiety of 3q using a Pd/C catalyst in a H2 gas environment smoothly produced product 8 in a
PDF
Album
Supp Info
Full Research Paper
Published 17 Apr 2025

Origami with small molecules: exploiting the C–F bond as a conformational tool

  • Patrick Ryan,
  • Ramsha Iftikhar and
  • Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

Graphical Abstract
PDF
Album
Review
Published 02 Apr 2025

Recent advances in allylation of chiral secondary alkylcopper species

  • Minjae Kim,
  • Gwanggyun Kim,
  • Doyoon Kim,
  • Jun Hee Lee and
  • Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

Graphical Abstract
  • wide range of 1,1-diborylalkanes bearing an N-tosyl-protected amine as well as alkene and alkyne moieties underwent efficient coupling with allylic bromides. A notable advantage of this synthetic approach is that it provides a distinct alternative to traditional CuH-catalyzed allylic alkylation
PDF
Album
Review
Published 20 Mar 2025

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

  • Olesja Koleda,
  • Janis Sadauskis,
  • Darja Antonenko,
  • Edvards Janis Treijs,
  • Raivis Davis Steberis and
  • Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

Graphical Abstract
  • , the cyclization of the amino acid fragment-containing monoesters 9l,m afforded dipeptides 6l,m in 36% and 50% yield, respectively. Notably, the decarboxylative cyclization is compatible with the alkene moiety (product 6m). Both dipeptides 6l,m were obtained as a 67:33 mixture of diastereomers. In the
PDF
Album
Supp Info
Full Research Paper
Published 19 Mar 2025

Formaldehyde surrogates in multicomponent reactions

  • Cecilia I. Attorresi,
  • Javier A. Ramírez and
  • Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

Graphical Abstract
  • –Alder reaction between an imine and an alkene (Scheme 6). Very successfully, the multicomponent version of the Povarov reaction using aldehydes, anilines, and alkenes has been explored in a three-component cascade reaction to quinolines [28][29][30][31] (Scheme 6). Furthermore, protocols have been
  • developed in which the alkene compound has been replaced with other surrogates for electrophilic addition, such as ketones [32][33][34]. In the case of the carbonyl component, it is generally an aromatic aldehyde [30][33][34] and there are not many reports on using formaldehyde in the Povarov reaction. In a
  • the alkene moiety of the amine. The resulting stabilized carbocation 15 is then captured by formaldehyde (generated in situ from DMSO) leading to an intermediate oxocarbenium 16 that undergoes a cyclization to obtain the sulfenylated oxazinane derivative 13. In isotope labelling experiments using DMSO
PDF
Album
Review
Published 13 Mar 2025

Cryptophycin unit B analogues

  • Thomas Schachtsiek,
  • Jona Voss,
  • Maren Hamsen,
  • Beate Neumann,
  • Hans-Georg Stammler and
  • Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

Graphical Abstract
  • containing a dimethylamino motif did not require an additional protecting group, ring closure was performed through alkene cross metathesis, which has been accomplished reliably and with good yields for other cryptophycins [11][26][27]. However, for the synthesis of a cryptophycin with a monomethylated amino
  • group in unit B a suitable protecting group, i.e., allyloxycarbonyl (Alloc), must be used. Since the presence of this allylic double bond would most likely interfere with a clean reaction outcome after alkene cross metathesis, we decided for a more classical ring-closure strategy through
PDF
Album
Supp Info
Full Research Paper
Published 07 Mar 2025

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

  • Yujun Pang,
  • Jinglan Yan,
  • Nawaf Al-Maharik,
  • Qian Zhang,
  • Zeguo Fang and
  • Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

Graphical Abstract
  • of our ongoing interest in radical cyclization reactions [22][23][24][25][26], we report here a sustainable and efficient protocol for synthesizing difluoromethylated and aryldifluoromethylated polycyclic imidazoles via visible-light-promoted cyclization of unactivated alkene-containing imidazoles
PDF
Album
Supp Info
Letter
Published 30 Jan 2025

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

  • Seungmin Lee,
  • Minsuk Kim,
  • Hyewon Han and
  • Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

Graphical Abstract
  • bearing linear alkyl groups were transformed into N-acyl amidines 10a–c by copper catalysis. Moreover, good functional group tolerance was observed with a terminal alkene motif (10d). The cyclohexyl-substituted dioxazolone successfully provided the corresponding N-acyl amidine 10e. However, the
PDF
Album
Review
Published 22 Jan 2025

Recent advances in electrochemical copper catalysis for modern organic synthesis

  • Yemin Kim and
  • Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

Graphical Abstract
  • an alkene to generate a radical intermediate, followed by oxidation, which enables radical-polar crossover (RPC) and the subsequent nucleophilic attack of the cationic intermediate [67]. Alternatively, the initial radical intermediate can be trapped by a transition-metal catalyst, followed by a cross
  • enantioselective radical cyanation. In the proposed catalytic cycle, Co(III)–H species 92 are initially formed from the anodically oxidized Co(III) complex 91 and hydrosilane 88 (Figure 15). Subsequently, the HAT between the Co(III)–H catalyst 92 and the alkene 27 generates a carbon-centered radical species 93
  • reacts with the alkene 97 to produce an alkyl radical 104, which undergoes ligand transfer from Cu(II)(N3)2 (102) to yield the diazidation product 99 and Cu(I)(N3) (100). The Cu(I)(N3) (100) is reoxidized to Cu(III)(N3)3 (101) on the anode in the presence of N3- to complete the catalytic cycle. In 2024
PDF
Album
Review
Published 16 Jan 2025

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

Graphical Abstract
  • , respectively. The latter interacts with the alkene generating an alkyl radical IV that converts to the cationic intermediate V by single-electron oxidation by the Cu(II) species. Finally, the attack of the nucleophile leads to the desired products 6. Starting from aryl carbazates, intermediate II, adds
  • directly to the alkene, then reacts with the nucleophile to afford product 7. The regioselective 1,2-difunctionalization of allyl alcohol has been developed as a three-component cascade reaction using arenes and sulfonamides as nucleophiles to achieve arylation/hydroamination processes. The reaction
  • begins with a nucleophilic attack of hydrazine on the aldehyde, activated by the copper salt, to give the corresponding hydrazone XXVIII. Subsequently, the formation of a Mannich-type intermediate XXIX was hypothesized by interaction between the hydrazone and the alkene mediated by Cu(OTf)2 coordination
PDF
Album
Review
Published 14 Jan 2025

Recent advances in organocatalytic atroposelective reactions

  • Henrich Szabados and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

Graphical Abstract
  • ) cyclization of alkynylindolylmethanols 170 and 2-naphthols 171 mediated by chiral phosphoric acid C37 leading to axially chiral aryl-alkene-indoles 172 (Scheme 50) [78]. Very high enantioselectivities and E/Z ratios, along with, on average, decent yields, were reported. Slow racemization was observed at 40 or
PDF
Album
Review
Published 09 Jan 2025

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

Graphical Abstract
  • cycloadducts 29e and 31e in good yields (Scheme 12). Further derivatizations were also carried out: The treatment of 29e with SOCl2 led to interesting unsaturated derivative 32 in a 54% yield. The acetylation of 31e provided 33 in 76% yield. Next, an alkene metathesis of 33 with styrene led to product 34 in 72
  • stepwise mechanism could be also feasible (path b). In the latter, the addition of the alkene to the azadiene is occurring first and leads to an intermediate which then undergoes an intramolecular cyclization to yield product 62f. In both pathways, the hydrogen-bonding interaction between the substrate and
PDF
Album
Review
Published 10 Dec 2024

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

  • John M. Halford-McGuff,
  • Thomas M. Richardson,
  • Aidan P. McKay,
  • Frederik Peschke,
  • Glenn A. Burley and
  • Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

Graphical Abstract
  • established as a powerful approach for molecule synthesis. Strategies within click chemistry include several widely used reactions such as the (hetero-)Diels–Alder reaction [1][2], alkene hydrothiolation [3], and an array of amide-bond-forming chemistries [4]. However, by virtue of the access to alkyne and
PDF
Album
Supp Info
Full Research Paper
Published 05 Dec 2024

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

Graphical Abstract
  • firstly through the coordination of an alkene by the HVI reagent, which activates it toward intramolecular attack by an internal nucleophile. Following this, substitution of the iodane(III) can occur from the nucleophilic halide in solution to reveal the halo-cyclised product (Figure 2). In this review
  • this review aims to fill. The synthetic uses of HVI reagents [14][15][16], their involvement in heterocycle synthesis [17][18][19], and alkene functionalisation [20][21], have each been well-reviewed elsewhere. Review Hypervalent iodine-mediated fluorocyclisation Fluorine can substantially improve the
  • fluoride and BF3·OEt2 as activator. A range of unsaturated amines 5 were cyclised to racemic β-fluorinated piperidines 6. Good yields were reported for all compounds except those with substituents present on the alkene. Homologation of the carbon chain from 5 to 6 carbons gave both 6- and 7-membered rings
PDF
Album
Review
Published 28 Nov 2024

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

Graphical Abstract
  • formation of tert-butoxy and tert-butylperoxy radicals from TBHP as a result of redox reactions with Cu(I)/Cu(II). The tert-butoxy radical abstracts the hydrogen atom from alkene 8 to form the C-centered radical A. The subsequent attack of the tert-butylperoxy radical on intermediate A leads to the
  • . Then the alkene interacts with the C-centered radical C leads to the formation of radical species D. Finally, recombination of D and B results in the formation of the target difunctionalization product 98. Related methods were subsequently proposed for the modification of coumarins 99 [92] in the
  • of hydrogen atom from TBHP with radical A. The interaction of hydrogen donors (R–H) with radical A or B generates C-centered radical C. Then two ways of reaction proceeding are possible: the interaction of alkene 99 with C-centered radical C or with tert-butylperoxy radical B leads to the formation
PDF
Album
Review
Published 18 Nov 2024

Copper-catalyzed yne-allylic substitutions: concept and recent developments

  • Shuang Yang and
  • Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

Graphical Abstract
  • acetylide-bonded allylic cation as the key intermediate is proposed (Scheme 6a). It is worth noting that the nucleophilic attack favors a less sterically hindered site. Therefore, disubstituted alkene moiety prefers γ-attack while trisubstituted alkene moiety is inclined to α-attack (Scheme 6b). Lin and He
PDF
Album
Review
Published 31 Oct 2024

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

Graphical Abstract
  • carbocation intermediate, which rearomatizes through proton loss. Concurrently, the cathodic reduction of the generated protons produces H2. In addition to (hetero)aromatic groups, alkene scaffolds also underwent this reaction (Scheme 3). In the same year, the Lei group [10] extended the electrochemical C(sp2
  • that dimerize to form iodine (I2). Subsequent anodic oxidation of in-situ formed Et3N produced an α-amino radical. The iodine then reacts with the alkene to form an iodonium intermediate, which undergoes intramolecular cyclization with losing an electron, and a second water attack to yield the desired
  • =C bond in the Co–alkene complex, forming an intermediate alkyl radical, which is further anodically oxidized to produce an intermediate alkyl cation. Another indole molecule undergoes electrophilic alkylation by this intermediate, forming an indolyl cation, which upon deprotonation yields the final
PDF
Album
Review
Published 09 Oct 2024

Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams

  • Valentina Giraldi,
  • Giandomenico Magagnano,
  • Daria Giacomini,
  • Pier Giorgio Cozzi and
  • Andrea Gualandi

Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210

Graphical Abstract
  • the linked alkene moiety, followed by hydrogen transfer from the hydrogen atom transfer (HAT) catalyst. This process was used to successfully prepare 2-alkylated clavam derivatives. Keywords: β-lactam; acridinium photocatalyst; alkenes; amides; intramolecular radical reaction; photoredox catalysis
  • ; Introduction Access to nitrogen radicals for the functionalization of alkenes is a field under active investigation [1][2][3][4], as it gives the possibility to directly introduce nitrogen into an alkyl chain (alkene carboamination) to obtain valuable nitrogen-containing molecules [5][6]. Among several N
  • functionalization of amides with alkenes under photoredox conditions. Another viable approach for amide functionalization through photoredox catalysis involves the nucleophilic addition, in the presence of base, of an amide to a radical cation obtained by oxidation of an unfunctionalized alkene moiety (Figure 1A
PDF
Album
Supp Info
Full Research Paper
Published 01 Oct 2024

Hypervalent iodine-mediated cyclization of bishomoallylamides to prolinols

  • Smaher E. Butt,
  • Konrad Kepski,
  • Jean-Marc Sotiropoulos and
  • Wesley J. Moran

Beilstein J. Org. Chem. 2024, 20, 2455–2460, doi:10.3762/bjoc.20.209

Graphical Abstract
  • the alkene and the amide increased from two to three atoms. In the latter case, cyclization at the amide nitrogen to form the pyrrolidine ring was favored over cyclization at the amide oxygen. A DFT study was undertaken to rationalize the change in mechanism of this cyclization process. In addition
  • 2019, we reported our DFT study on the cyclization of N-allylbenzamide (1a) to the 2-oxazoline 4a, i.e., where n = 1 and Ar = Ph [18]. This work indicated that the alkene is activated by the iodine(III) species and that this triggers cyclization. Intrigued by the change in mechanism from O- to N
  • -cyclization onto the alkene when n = 3, we modelled this reaction using DFT calculations (Scheme 2). Similarly, we concluded that the present reaction commences with activation of the olefin in 3a by the hypervalent iodine species 8, which is generated under the reaction conditions. The activation occurs via
PDF
Album
Supp Info
Full Research Paper
Published 30 Sep 2024
Other Beilstein-Institut Open Science Activities