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

• acid, the conditions reported in entry 9 of Table 1 were chosen as reference for the study of the reactivity of different alkynes. For the internal alkyl(aryl)alkynes a regioselective hydration occurred, with the only generation of the corresponding aryl ketones, formed after the attack of water to the

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

• , tetrahydrofuran or tetrahydropyran can smoothly react with many methyl aryl ketones to obtain the desired coupling products (Scheme 6a) [54]. The mechanism of the dehydrogenation cross-coupling reaction may undergo a radical pathway. Initially, the tert-butoxy radical produced by the dissociation of t-BuOOH may

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• strategy for aldehyde C–H activation. The acyl radicals generated in this step were arylated with aryl bromides through a well stablished nickel cross-coupling methodology, leading to a variety of interesting aryl ketones in good yields. We also performed computational calculations to shine light in the

• through this step were used in a well-stablished nickel-catalyzed cross-coupling reaction [19][27][28][29][30] with aryl bromides as a proof of concept, leading to the synthesis of aryl ketones. We also present computational calculations of the HAT reaction step with the DABCO radical cation as the

• endergonic with barriers lower than the one presented for the reaction with 1 (see Supporting Information File 1, Table S7). Conclusion In conclusion, we report the use of DABCO as a HAT abstractor for aldehyde activation in a photoredox strategy. Several aryl ketones were synthesized with moderate to

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

• 'R)-isomer 28-7a and (2'S,3S,5'R)-isomer 28-7b in 81% and 44% yield, respectively. Figure 9 summarizes the outcomes of asymmetric fluorination reactions of enolates of aryl ketones using 28-7a and -7b. In the event isomer 28-7a yielded much better ees than 28-7b. Although 28-7a gave a maximum 70% ee

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• ), and notably, hydroalkylation products were produced from α-aryl ketones, from more acidic substrates like 4a, and from α-alkyl ketones, including the less activated methyl ketone 4c. Examples of intermolecular hydroalkylations of olefins using Pd were much scarcer than their intramolecular

Synthesis of trifluoromethyl ketones by nucleophilic trifluoromethylation of esters under a fluoroform/KHMDS/triglyme system

• Yamato Fujihira,
• Yumeng Liang,
• Makoto Ono,
• Kazuki Hirano,
• Takumi Kagawa and
• Norio Shibata

Beilstein J. Org. Chem. 2021, 17, 431–438, doi:10.3762/bjoc.17.39

• ketone 2b in only lower yield (37%). Functionalities on the benzene ring at the para-position were well-tolerated in the KHMDS/glyme system. Halogen groups, such as chloro (1c), bromo (1d), and reactive iodo (1e) substitutions were also tolerated, resulting in the corresponding trifluoromethyl aryl

• ketones in moderate yields (56–63%) under basic conditions. The alkyl groups of tert-butyl (1f)- and cyclohexyl (1g)-substituted methyl benzoate derivatives, biphenyl benzoate (1h), and electron-donating 4-methoxybenzoate, were nicely transformed into aryl trifluoromethyl ketones in moderate to high

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• visible-light-inactive molecules using PSCats 3.1 Benzylic C–H fluorination A seminal paper in the field of transition-metal-free direct C–H fluorination comes from Chen and co-workers, who applied aryl ketones as PSCats [135]. They discovered that the choice of the PS impacted the selective formation of

NHC-catalyzed enantioselective synthesis of β-trifluoromethyl-β-hydroxyamides

• Alyn T. Davies,
• Mark D. Greenhalgh,
• Alexandra M. Z. Slawin and
• Andrew D. Smith

Beilstein J. Org. Chem. 2020, 16, 1572–1578, doi:10.3762/bjoc.16.129

• proceed via enamine intermediates (Figure 1B) [14][15][16][17][18][19]. The state of the art within this area has been recently demonstrated by Dixon and co-workers, who showed that bifunctional BIMP catalysts could promote the enantioselective addition of typically recalcitrant aryl ketones to

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• the diazonium salts, as well as the enol acetates are reported giving versatile α-aryl ketones/aldehydes in both batch and continuous-flow conditions (20 examples in 26–88% yields) [9]. A comparison between batch and flow conditions was performed showing that similar yields are obtained (batch 82% vs

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

• known photocatalysts, such as aryl ketones (Scheme 3) [15][16][17]. Later, Steel and co-workers examined the photochemical properties of benzaldehyde (8), studying the EnT from 8 to azo compounds [18]. Upon the irradiation and excitation of benzaldehyde (8), the phosphorescence was quenched either by

• aryl ketones, could participate in HAT processes as hydrogen atom abstractors [20]. More specifically, aldehydes can absorb irradiation at 300 nm and be excited from their ground state S0 to their singlet state S1 (n,π*), Then, through intersystem crossing (ISC), they can transition to a lower energy

• irradiation, supporting the other two pathways. Also, mechanistic studies by Cui et al. showed that the energy levels of the reactions (1) and (2) in Scheme 5 were closely tied, so distinguishing them is not always trivial [32]. The triplet state quenching of 8 and related compounds, such as aryl ketones, has

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• alcohols 98–100, respectively. Palladium was no longer needed for these transformations. The scope of the reaction with ketones was not limited to diaryl species and aryl ketones participated in the reaction, including those with more hindered alkyl groups (Scheme 19) [44]. This discovery was followed by a

Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical complex

• Yoichi Kobayashi,
• Yukie Mamiya,
• Katsuya Mutoh,
• Hikaru Sotome,
• Masafumi Koga,
• Hiroshi Miyasaka and
• Jiro Abe

Beilstein J. Org. Chem. 2019, 15, 2369–2379, doi:10.3762/bjoc.15.229

• unit because aryl ketones have been widely used as visible-light photosensitizers [36]. While most of aryl ketones were used as triplet photosensitizers, the benzil unit in the present study acts as a singlet photosensitizer. The detail of the sensitization processes was investigated by wide ranges of

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

• . Substituted aryl ketones, heteroaryl methyl ketones, and α,β-unsaturated methyl ketones were also well tolerated by the reaction (Scheme 44). The reaction was also successful in a two-step procedure in which the product of 2-AP and ketone can also be subjected to cyanation with benzyl cyanide thereby proving

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• ). Starting from several aryl and aliphatic ketones 89, more than thirty isoindolinones 90 were obtained, with three points of diversity around the lactam core. Overall, aryl ketones containing electron-donating and electron-withdrawing functions and even a heteroaryl group delivered better yields than

Selective benzylic C–H monooxygenation mediated by iodine oxides

• Kelsey B. LaMartina,
• Haley K. Kuck,
• Linda S. Oglesbee,
• Asma Al-Odaini and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55

• –H bonds (≈80–90 kcal/mol) make selective functionalization possible [1][2]. The installation of oxygen functionality at benzylic C–H bonds allows for the production of benzylic alcohols, aryl ketones, and aryl carboxylic acids, which are useful chemical building blocks. Strategies that prevent over

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• first a nucleophilic attack from the vinylogous ester, then by the aromatic group, providing the final outcomes. Wirth and co-workers developed an oxidative rearrangement of alkenes to chiral α-aryl ketones, in which electron-deficient chiral lactic acid-based hypervalent iodine reagents were

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• disubstituted products 1 and 2 are obtained respectively from aliphatic ketones and methyl aryl ketones. The reaction conditions have then been extended to the functionalization of alkenes to afford 1,2-halo-oxygenated compounds 3 (Scheme 2b) [29]. This transformation has recently been used for the

A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

• Anna Czarnecka,
• Emilia Kowalska,
• Agnieszka Bodzioch,
• Joanna Skalik,
• Marek Koprowski,
• Krzysztof Owsianik and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2018, 14, 1229–1237, doi:10.3762/bjoc.14.105

• ortho-1,3-dithianylaryl(aryl)methanols leading to ortho-1,3-dithianylaryl(aryl)methanes using the ZnI2-Na(CN)BH3 reductive system (Scheme 1). The use of zinc iodide is critical in this system. It was used for the first time in dichloroethane by Lau et al. to reduce aryl ketones, aldehydes, benzylic

Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system

• Toshifumi Dohi,
• Shohei Ueda,
• Kosuke Iwasaki,
• Yusuke Tsunoda,
• Koji Morimoto and
• Yasuyuki Kita

Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94

• oxidation forming aryl ketones [52]. Note that the successful coupling of a range of secondary and tertiary carboxylic acids now supports the direct and selective C–H bond activation at the benzyl position by avoiding the formation of carbonyloxy radicals, which are susceptible to decarboxylation. In

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• carboxylic acid is also available via basic hydrolysis of ferrocenyl aryl ketones [61]. Together with the redox potentials of ferrocene, 1 and 2, the hitherto unknown electrochemical potentials of 3 and 4 should cover a wide potential range. This will meet the requirements of different substrates for the

High-speed vibration-milling-promoted synthesis of symmetrical frameworks containing two or three pyrrole units

• Marco Leonardi,
• Mercedes Villacampa and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2017, 13, 1957–1962, doi:10.3762/bjoc.13.190

• -iodoketones (2 molecules), prepared in situ from aryl ketones, was performed efficiently under mechanochemical conditions involving high-speed vibration milling with a single zirconium oxide ball. This reaction afforded symmetrical frameworks containing two pyrrole or fused pyrrole units joined by a spacer

• mechanochemical conditions. In this context, we present here our results on the development of pseudo-five-component reactions allowing the construction of bispyrrolic systems 1 starting from β-dicarbonyl compounds 2, diamine derivatives 3 and aryl ketones 4, together with some related additional methodology. The

α-Acetoxyarone synthesis via iodine-catalyzed and tert-butyl hydroperoxide-mediateded self-intermolecular oxidative coupling of aryl ketones

• Liquan Tan,
• Cui Chen and
• Weibing Liu

Beilstein J. Org. Chem. 2017, 13, 1079–1084, doi:10.3762/bjoc.13.107

• self-intermolecular oxidative coupling of aryl ketones using I2−tert-butyl hydroperoxide (TBHP). Under the optimum conditions, various aryl ketones gave the corresponding products in moderate to excellent yields. A series of control experiments were performed; the results suggest the involvement of

• H2O in the TBHP solvent. Keywords: aryl ketones; iodine; self-intermolecular oxidative coupling; self-sequential assembly; TBHP; Introduction In recent years, α-acetoxyaryl ketones have attracted considerable interest because this structural motif is found in a variety of biologically active natural

• been made [12], examples of the synthesis of α-acetoxyaryl ketones through self-intermolecular oxidative coupling of aryl ketones are still rare. Yan and coworkers reported the preparation of α-acyloxyaryl ketones from aryl ketones using a Pybox-copper(II) catalyst [13]. However, the substrate scope

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• reoxidation of Pd(0) as the reaction couldn't proceed with a stoichiometric amount of Pd(OAc)2 under argon. In 2012, the Rao group and the Dong group simultaneously reported a palladium catalyzed ortho-hydroxylation of aryl ketones, and thus further broadened the directing groups of arene substrates [70][71

• trifluoroacetates rather than phenols as products, phenols were readily obtained during the silica gel column chromatography. In 2013, an acid-free procedure for the regioselective hydroxylation of aryl ketones was reported by Kwong and co-workers [72]. They used Pd(OAc)2 as catalyst and PhI(OTFA)2 as oxidant

• tolerated, giving a variety of phenols. Further studies found that this protocol could also be readily applied in the hydoxylation of aryl ketones [76]. Competition experiments showed that an electron-donating group was more feasible for this conversion than an electron-withdrawing group. In 2013, the

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• the synthesis of functionalized ketones and alcohols, including γ-hydroxy enones. The Dakin oxidation finds application for the synthesis of phenols from arylaldehydes or aryl ketones and the Elbs persulfate oxidation allows the preparation of hydroxyphenols from phenols. Finally, the Schenck and