Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• mechanism discussed in Scheme 7B. Lastly, radical–radical coupling between 64 and 147, accompanied by elimination of the NHC catalyst, yields ketone product 149. In subsequent studies, this NHC-catalyzed radical relay activation mode has been extended to the alkylation of aliphatic aldehydes [107] and to

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

• π-CPCs relies on the extrusion of carbon monoxide (CO) from soluble precursors incorporating bridging ketone fragment(s). In contrast with the thermal activation required in retro-Diels–Alder reactions, photoirradiation of α-diketones triggers a Strating–Zwanenburg decarbonylation leading to the

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

• 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

• electrochemical conditions. Experimental General procedure of anodic oxidation Compound 1 (145 mg, 0.2 mmol), Bu4NPF6 (387 mg, 1 mmol), CH2Cl2 (10 mL), phosphate base (90 mg, 0.2 mmol) and methyl vinyl ketone (32.7 μL, 0.4 mmol) were added to a test tube, which was then subjected to a constant electrical current

• in vacuo and the resulting residue was subjected to 1H NMR spectroscopy or column chromatography. A divided-cell experiment was performed using an H-type cell (4G glass filter). Compound 1 (0.2 mmol), Bu4NPF6 (387 mg, 1 mmol), phosphate base (90 mg, 0.2 mmol), CH2Cl2 (10 mL), and methyl vinyl ketone

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• -annelated IF-DTF 12 by removal of the tosyl (Ts) group under alkaline conditions, followed by nucleophilic substitution to incorporate the hexyl chain on the pyrrole. Furthermore, treatment of the IF-DTF ketone 4 with Lawesson’s reagent (using a recently established protocol [20]) yielded the large dimer 13

• as a mixture of E and Z isomers (ca. 4:1). Further functionalization of the IF-DTF ketone 11 was obtained by Ramirez/Corey–Fuchs dibromo-olefination and Knoevenagel condensation to yield vinylic dibromide 14 and diester 15, respectively, as illustrated in Scheme 2. We noted that the dibromo

• in Figure 6, and potentials against ferrocene (Fc/Fc+) (obtained from differential pulse voltammetry, see Supporting Information File 1) are summarized in Table 2. Compounds 11 and 15 showed two irreversible first oxidations at +0.34 V and +0.38 V vs Fc/Fc+, showing that replacing the ketone with the

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• University of Technology, Stremayrgasse 9, 8010 Graz, Austria 10.3762/bjoc.20.6 Abstract The reactions of 2,4-di-tert-butyl-6-(diphenylphosphino)phenol and various Michael acceptors (acrylonitrile, acrylamide, methyl vinyl ketone, several acrylates, methyl vinyl sulfone) yield the respective phosphonium

• carbanion [13][14]. Also with other Michael acceptors such as methyl vinyl ketone, several acrylates as well as methyl vinyl sulfone the reaction proceeds smoothly under the same reaction conditions (Scheme 1). Conversions of 1 are usually quantitative within 24 h and all phosphonium phenolates can be

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• well-known and useful reaction in organic chemistry, affording carbonyl compounds based on an atom-economical approach. Indeed, the addition of water to the triple bond of a terminal alkyne leads to the formation of the corresponding methyl ketone or aldehyde, in the case of Markovnikov or anti

• diphenylacetylene (1a), affording the corresponding ketones in high yields after 5 h. Otherwise, terminal alkynes generally showed higher reactivity compared to internal ones. For all the studied terminal alkynes, only ketone products (Markovnikov) were obtained, excluding the formation of the anti-Markovnikov ones

• 1f decreased the selectivity with respect to formation of the hydration product 2f, favouring the condensation product 3f (Table 4, entry 6). On the other hand, an ortho methyl group in 1g favoured formation of the ketone 2g, with a good yield, probably due to the steric hindrance of the aldol

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• Ar and CF3 groups can localize the negative charge and also provide steric effects to afford stereoselective cycloaddition products with 3:1 to 6:1 dr. The steric hindrance also prevents products 9 from undergoing a second cycloaddition. The control reactions of methyl ketone or benzaldehydes gave

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

•  1) exhibited signals corresponding to a spiro-carbon at δC 100.6 (C-9) and a ketone carbon at δC 213.3 (C-8). The HMBC correlations of H-10β/C-8, C-9, C-11, C-12; H-11/C-9, C-13; H2-13/C-9; H-16/C-7, C-8; and H3-18/C-11, C-12, C-13 and the connectivity confirmed by DQF-COSY indicated that 3 also

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• well-defined polymer brushes from polymer surfaces [170][171]. Photoinduced processes, including photoATRP and PET-RAFT were used [172][173][174][175]. Poly(aryl ether ketone)s such as poly(ether ether ketone), bearing a diaryl ketone moiety resembling that of benzophenone, can generate biradicals upon

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• 196.1 for a ketone group, 169.2 and 165.6 attributed to oxygenated aromatic carbons, and three other signals at δC 109.4, 106.2, and 16.6 (Figure S6 in Supporting Information File 1). On the other hand, each of the two aromatic methyl signals displayed a set of three cross peaks; the first one at δH

• 2.09 with the carbon signals at δC 165.6, 122.0, and 120.3, and the second one at δH 2.02 with the carbon signals at δC 169.2, 165.6, and 106.2 (Figure 2). These findings clearly indicated the presence of the 1,3-dimethylbenzene moiety linked to a side chain containing an ethyl group and a ketone group

• and 28.8. Hence, these key correlations permitted to assign the attachment of the hemiketal carbon (δC 106.1) to the ketone group and the benzene ring. Based on the above evidence, the structure of 1 was assigned with a trivial name of 5,7-dimethylpseudopithonone (Figure 1). Pseudopithonone was

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• reductive elimination to yield ketone 78. In the acylthiolation cycle, the azaphilic ZnCl2 activated NTSE 1’’’ via N–Zn coordination to facilitate the leaving ability of succinimide. Then, nucleophilic substitution of arylmagnesium bromide 75 to intermediate IV provided thioester 79. In 2022, Gao and co

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• by X-ray analysis (see Supporting Information File 1). Both, hydroxy ketone 1 and the corresponding enone 2, can be converted into the same indanone 3 in comparable yields; see pairs of reactions for 1a and 2a (indanone 3a), 1d and 2d (indanone 3d), 1i and 3i (indanone 3i), and 1n and 3n (indanone 3n

• -rich enones 2o,t,u, bearing electron-donating substituents in the aromatic rings, afford complex mixtures of oligomeric materials. The cyclization of hydroxy ketone 1k into indanone 3k is accompanied by demethylation of one of the methoxy groups (Scheme 6). The positions of hydroxy and methoxy groups

• delocalization of the positive charge from the carbonyl group to the aromatic ring. It should be mentioned that cation Bm was generated by two ways in TfOH: either directly by protonation of enone 2m or from hydroxy ketone 1m. The latter was found to undergo fast dehydration into enone 2m in TfOH at room

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• and the use of a ketone was necessary to induce C–H functionalization selectivity in preference to C=C functionalization. The products were obtained in moderate to high yields (Scheme 67). 2.6 N–H and C(sp2)–H carboxylation The application of the [(IPr)CuOH] complex as catalyst for the N–H/C(sp2)–H

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• the alkynyl-substituted 1,2-oxazin-4-ol derivative 19 which is smoothly available from the corresponding ketone 6 by highly stereoselective reduction with sodium borohydride [53]. Starting from 1,3- (8) or 1,4-bis(bromomethyl)benzene (16), respectively, the approved conditions in the presence of TBTA

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• elegant strategies on direct conversion of in situ-activated carboxylic acids for ketone synthesis [27][35][38], we chose dimethyl dicarbonate (DMDC, A1) as the activating reagent. To our delight, the reaction of 1a and 2 in the presence of NiBr2(dtbbpy) (10 mol %), Hantzsch ester (HE) and A1 in DMAc

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

• phosphate moiety was introduced via the use of bromoethyl dichlorophosphate 11.4 to produce 11.5. The reduction of the ketone with NaBH4 produced 11.6, and then the incorporation of the trimethylammonium group produced deoxy-lyso-PAF 11.7. Finally, the acetylation of the secondary alcohol produced racemic

• bio-imaging purposes [144]. In 1995, Mauleón et al. [145], extended this study by reporting the incorporation of a phenyl group in ω-position or by adding an alkyl group, a ketone or an alcohol function as illustrated in Figure 33. The idea of

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

• extract a hydrogen from the ether C (sp3)–H bond to form radicals. Subsequently, a single electron transfer (SET) leads to the oxonium species. Then, the enamine generated in situ from methyl aryl ketone and pyrrolidine undergoes a nucleophilic reaction with the oxonium species followed by hydrolysis to

• ketones 94 with ethers [81]. Contrary to what was obtained for the alkylation of coumarin at the carbonyl α-position, vinyl ketone undergoes Michael addition and ether addition at the β-position of the carbonyl (Scheme 20). The reaction delivered various alkylation products in good to excellent yields

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

• ketone-derived alcohols such as 1d (EWG = COPh, R = H), 1e (EWG = COn-Pr, R = H), 1f (EWG = COc-C6H11, R = H) [42], and imidazole under the established reaction conditions and we have observed that the conversion was complete but was not clean. However, in methanol at reflux a clean reaction took place

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

• oxidation noted that the corresponding dimethyl amine – p-benzaldehyde oxidized at 0.79 V vs Fc/Fc+ and underwent a slow re-reduction [73]. Similar compounds, ketone derivatives rather than aldehyde, were developed with more negative potentials as anolytes for aqueous and non-aqueous RFBs by Sanford and co

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• into a ketone moiety diminished the activity [31]. Similar findings on the related polyporenic acid B, with significant IC50 values between 8.4–12.2 µM [22], confirms the probable crucial role played by the 3-OH group in improving the potency. The presence of the 3-O-methylglutaroyl functionality in

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

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

• provided ketone 138 which was reacted with an α-keto ester in an intramolecular 5-endo-trig-cyclization process to afford 139. Treatment of compound 139 with sodium borohydride afforded secondary alcohol 140 which after conversion of the tosyl group into a methyl group gave the final product 141 (Scheme 35

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• attributable to two methyl groups, two methoxy carbons, one methylene, three methines (one sp2 and one of them oxygenated), one ketone, and five sp2 carbons (two of them oxygenated). Some of these signals resemble those of 8-O-methylteratosphaerone B [17], suggesting compound 1 being an analogue, but with an

• NMR and DEPT spectra (Table 2 and Figure S9 in Supporting Information File 1) show that compound 2 is comprised of 9 carbons, including one methyl, one methoxy carbon, one sp2 methine, one ketone, and five sp2 carbons (three of them oxygenated). The 1H and 13C NMR data and the molecular formula

• -tetrasubstituted benzene substructure. The 13C NMR and DEPT spectra of 3 (Table 2 and Figure S15 in Supporting Information File 1) exhibit 15 resonances classified into two methyls, four sp2 methines, one ketone, and eight sp2 carbons (four of them oxygenated). The two methyl groups are positioned at C-3 and C-5

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• dibenzocyclooctyne 8 and tetracyclone 2 in a 91% yield. After a subsequent sequence of deprotection and oxidation, ketone 10 was obtained. Through the oxidative cyclodehydrogenation reaction of 10 in the presence of DDQ and trifluoromethanesulfonic acid (TfOH), a saddle-helix hybrid nanographene 11, bearing an

• this [7]helicene family by introducing different linkers such as nitrogen, sulfur, sulfone, ketone, methylene, and derivatives of ketone [44]. Due to the varied nature of the different linkers, the photophysical and semiconductor properties can be effectively tuned. Feng and co-workers reported a

• the P,P, and M,M enantiomers. The isomerization barrier was determined as 44.7 kcal/mol at 260 °C by HPLC analysis. Meanwhile, Campaña and co-workers reported a similar chiral, tropone-containing HBC-dimer 53 [47]. Ketone 47 was transformed to compound 48 by reacting with 1-iodo-4-(phenylethynyl

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

• . Therefore, numerous structurally distinct substrates were successfully utilized. Other than nitroolefins, Liao and co-workers have observed a side reaction of the α,β-unsaturated ketone 26 and the enolate 27 when they studied the conjugate addition of R2Zn reagents to chalcone and its derivatives (Scheme 7A

• nucleophile (R3Zn−) to the ketone with moderate yields but still good stereoselectivities (Scheme 9B). In 2018, Wang and co-workers extended the group of applicable electrophiles for the zinc enolate-based tandem reactions. Following the conjugate addition of Et2Zn to acyclic α,β-unsaturated ketones 41, they

• , which begins with a Cu-catalyzed enantioselective conjugate addition/enolate alkylation tandem reaction sequence utilizing the N-heterocyclic carbene ligand L40 [112]. Ketone 232 was isolated in 61% yield and 81% ee. Hereafter, the authors were able to synthesize the complex tetracyclic structure within