Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• advantages over the related enol silyl ethers [24][25]: they are more stable towards acidic conditions, their electronic character contributes to high regioselectivity in cycloaddition reactions, and they can be converted to many other functions, including their hydrolysis to ketones [26]. In the other hand

• obtained when using equimolar amounts of both 19 and 11b (Table 1, entries 1 and 2). These disappointing results with alkyne 19 prompted us to investigate the coupling with an organometallic reagent derived from vinyl iodide 20. This reagent was already synthesized and coupled with acyclic ketones in

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• cycle can also lead to different reaction outcomes, e.g., rearrangements, desaturations or epoxidations. Multiple oxidation rounds, leading to aldehydes/ketones or carboxylic acids, are also commonly observed. Together, this versatile oxidative chemistry makes CYPs key enzymes in specialised metabolism

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

• Shang-Feng Yang,
• Pei Li,
• Zi-Lin Fang,
• Sen Liang,
• Hong-Yu Tian,
• Bao-Guo Sun,
• Kun Xu and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• and Life, Beijing University of Technology, Beijing 100124, China 10.3762/bjoc.18.130 Abstract The electrochemical preparation of 2-aminothiazoles has been achieved by the reaction of active methylene ketones with thioureas assisted by ᴅʟ-alanine using NH4I as a redox mediator. The electrochemical

• protocol proceeds in an undivided cell equipped with graphite plate electrodes under constant current conditions. Various active methylene ketones, including β-keto ester, β-keto amide, β-keto nitrile, β-keto sulfone and 1,3-diketones, can be converted to the corresponding 2-aminothiazoles. Mechanistically

• ], dyes [13], etc. These important features of thiazoles have driven intense interests in their facile synthesis [14][15][16][17]. Among various synthetic routes to the thiazole unit, the Hantzsch condensation of α-halo ketones (dielectrophiles) with various thioureas (dinucleophiles) should be the most

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• intramolecular aldol addition of ketones such as 7 (Scheme 2) [5]. Brønsted-acid catalysis leads via a transition state 8 to the aldol 9, while the use of chelating Lewis acids results via 10 in the epimeric aldol 11. This review is a collection of total syntheses of natural products where vicinal keto esters

Lewis acid-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence to access phosphoric esters

• Jin Yang,
• Dang-Wei Qian and
• Shang-Dong Yang

Beilstein J. Org. Chem. 2022, 18, 1188–1194, doi:10.3762/bjoc.18.123

• accomplished the synthesis of phosphoric esters through a 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence [43]. A decade later, Chakravarty and colleagues reported the efficient synthesis of organic phosphates from ketones and aldehydes using n-BuLi as

• , all of the above transformations were carried out under basic conditions, and thus impose barriers for substrates that bear base-sensitive functional groups. More importantly, heteroatom-containing ketones and aldehydes have been proven to be challenging substrates for all of these existing systems

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• recently, two publications from the Werz group appeared concerning anodic activation of donor–acceptor cyclopropanes followed by their functionalization with arenes [43] or yielding oxy-ketones or 1,2-dioxanes [44]; the latter process was inspired by a previous report of Buriez [45]. The anodic

Synthesis of N-phenyl- and N-thiazolyl-1H-indazoles by copper-catalyzed intramolecular N-arylation of ortho-chlorinated arylhydrazones

• Yara Cristina Marchioro Barbosa,
• Guilherme Caneppele Paveglio,
• Claudio Martin Pereira de Pereira,
• Sidnei Moura,
• Cristiane Storck Schwalm,
• Gleison Antonio Casagrande and
• Lucas Pizzuti

Beilstein J. Org. Chem. 2022, 18, 1079–1087, doi:10.3762/bjoc.18.110

• o-chloroarylketones are the starting material [27][28]. The preference for the use of o-bromo analogues is due to to the better yield obtained compared to using o-chloroarylhydrazones. However, the availability of commercial o-chloroarylaldehydes and o-chloroaryl ketones is greater than that of

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

• Koichi Mitsudo,
• Haruka Inoue,
• Yuta Niki,
• Eisuke Sato and
• Seiji Suga

Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

• proton-exchange membrane reactor is described. The reduction of enones proceeded smoothly under mild conditions to afford ketones or alcohols. The reaction occurred chemoselectively with the use of different cathode catalysts (Pd/C or Ir/C). Keywords: enone; hydrogenation; iridium; palladium; PEM

• reactor; Introduction Catalytic hydrogenation of α,β-enones is a significant transformation in organic synthesis [1]. Hydrogenation of enones can give ketones, allyl alcohols, and saturated alcohols, and the control of the chemoselectivity is important. Therefore, there have been numerous studies on the

• cathodic chamber and are reduced by the catalyst of the MEA to monoatomic hydrogen species (adsorbed hydrogen, Had) [22]. Thus generated Had reduces enones 1 to give the corresponding hydrogenated products (ketones 2 and alcohols 3). The expected advantage of PEM reactors is that the reactivity of Had

Electrochemical vicinal oxyazidation of α-arylvinyl acetates

• Yi-Lun Li,
• Zhaojiang Shi,
• Tao Shen and
• Ke-Yin Ye

Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103

• vinyl acetates has been developed to afford the corresponding α-fluorinated [26], -arylated [27], and -sulfenylated [28] ketones (Scheme 1B). In addition, electrochemical azidation [29][30][31][32][33] has also become a robust and reliable synthetic tool to incorporate azido functionality [34][35] into

• ketones, such as cyclohexanone (see Supporting Information File 1 for details). As illustrated in Scheme 3, the synthetic utility of α-azidoketone was further evaluated [37][38]. Click reaction between 2-azido-1-phenylethan-1-one (2) and ethisterone (28) [39][40][41] readily afforded the target triazole

New azodyrecins identified by a genome mining-directed reactivity-based screening

• Atina Rizkiya Choirunnisa,
• Kuga Arima,
• Yo Abe,
• Noritaka Kagaya,
• Kei Kudo,
• Hikaru Suenaga,
• Junko Hashimoto,
• Manabu Fujie,
• Noriyuki Satoh,
• Kazuo Shin-ya,
• Kenichi Matsuda and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102

• alcohols [24], methoxides [23][25][26], carboxylic acids [27], amides [28], ketones [29][30], an exo-olefin [31], and lactones [32]. Elucidating the mechanisms of structural diversification is essential when considering the synthesis of unnatural azoxides by a synthetic biology-based approach. However

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• flowers of orchids among with the structurally related and better known Ambrettolide [(Z)-7-hexadecen-16-olide], having a sweet odor with “great tenacity and fixative power” [9][48]. Notably, and already in 1970, Story and co-workers described that cyclic ketones can be reacted with hydrogen peroxide

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• applications. NiO2, on the other hand, was used to achieve the dehydrogenation of amines (to nitriles) and to perform the α,β dehydrogenation of ketones 61. 3.2.3 Using chemically active fixed beds (catalysts): Copper metal in the form of wires or turnings can also be inductively heated when placed inside flow

• oxidations of alcohols to aldehyes or ketones using gold nanoparticles in the presence of oxygen gas or atmospheric air was achieved by modifying the silica shell of nanostructured MagSilicaTM with gold nanoparticles (Scheme 12, case B). After heating these modified SPIONs in an electromagnetic field, a

• fixed-bed materials serving as catalysts: A. with copper metal, B. with Au-doped MagSilicaTM, and C. with Pd-doped MagSilicaTM. Two step flow protocol for the preparation of 1,1'-diarylalkanes 77 from ketones and aldehydes 74, respectively, and boronic acids 76. O-Alkylation, the last step in the

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• compounds (aldehydes and ketones) enable to obtain the products of formal [5 + 2] cycloaddition reactions ‒ 2-benzazepines [8] and 2-benzoxepines [9][10]. When studying the Rh(II)-catalyzed reaction of DAS with ketones [10], we attempted to involve poorly reactive fluorenone in the reaction. To our surprise

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• generation of new cascade reactions to construct carbo- and heterocyclic moieties [27][28], we aimed to synthesize dispirocyclopentanebisoxindoles in one pot operation using a new protocol. Chemical hydrogenation of double bonded compounds like α,β-unsaturated ketones, approaching to saturated ketones, is an

• -unsaturated ketones [29]. Using this method, we developed the in situ reduction of 3-phenacylideneoxindoles by tosylhydrazine and sequential Micheal addition/cyclization with another molecule of 3-phenacylideneoxindole towards bisspirocyclopentenebisoxindole derivatives. Although Shanthi et al. [30] reported

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• , β-ketoesters or β-ketoamides are a commonly used 2-step route to 3,4,5-trisubstituted isoxazoles [24][25]. Xiao Zhou et al. recently reported a direct access to 3,4,5-trisubstituted isoxazoles via an enolate-mediated 1,3-dipolar cycloaddition of β-functionalized ketones with nitrile oxides using

Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• -phenoxyketones, the most common methodologies are base-catalyzed alkylation of the corresponding phenols with halo- [28][29][30] and mesyl [31][32][33] ketones (Scheme 9), the preparation of which are not always selective and high-yielded. The ring opening of ArOCH2-epoxides [34][35], the SmI2-catalyzed

• reductive coupling of acid halides with ketones [36][37] and acetolyses of α-phenoxy-α-diazoketones [38] were also employed. Recently, F. P. Cossío et al. [39] have described a method for the preparation of benzo[b]furans by thermal heating of a dispersion of α-phenoxyketones in Al2O3. We involved the

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• aldehydes and ketones [128]. In this context, Fry and co-workers explored the electrophilic substitution reaction to synthesize 2-methyl-3-bromonaphthalene-1,4-dione (82), an important intermediate used for the synthesis of naphthoquinones functionalized with organochalcogens [127]. Compound 82 was obtained

Synthesis of 5-unsubstituted dihydropyrimidinone-4-carboxylates from deep eutectic mixtures

• Sangram Gore,
• Sundarababu Baskaran and
• Burkhard König

Beilstein J. Org. Chem. 2022, 18, 331–336, doi:10.3762/bjoc.18.37

• synthesis of 5-unsubstituted dihydropyrimidinone-4-carboxylate using gem-dibromomethylarene, oxalacetic acid, and urea [25]. Here the gem-dibromomethylarene moiety serves as an aldehyde equivalent. In addition, utilizing aromatic ketones as a β-ketoester equivalent, the synthesis of 5-unsubstituted DHPM

A Se···O bonding catalysis approach to the synthesis of calix[4]pyrroles

• Qingzhe Tong,
• Zhiguo Zhao and
• Yao Wang

Beilstein J. Org. Chem. 2022, 18, 325–330, doi:10.3762/bjoc.18.36

• ]pyrrole derivatives. The Se···O bonding interactions between selenide catalysts and ketones gave rise to the catalytic activity in the condensation reactions between pyrrole and ketones, leading to the generation of calix[4]pyrrole derivatives in moderate to high yields. This chalcogen bonding catalysis

• . Keywords: calix[4]pyrrole; chalcogen bonding; ketones; Se···O bonding interactions; supramolecular catalysis; Introduction Noncovalent catalysis has been established as one of the fundamental concepts in organic synthesis that enables achieving numerous chemical transformations [1]. Among these

• between ketones and pyrrole might take place to give calix[4]pyrrole derivatives under catalysis of a selenide catalyst. In the absence of a catalyst, no reaction took place. Indeed, even in presence of 5 mol % representative catalyst Ch1 [44], the condensation reaction between acetone and pyrrole worked

Regioselectivity of the S_EAr-based cyclizations and S_EAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

• Jonali Das and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

• reaction of 2-(1H-indol-4-yl)ethanamines 14 with various aldehydes/ketones 15, delivering a variety of azepino[3,4,5-cd]indoles 16 in a straightforward fashion in moderate to high yields (Scheme 5B) [15]. The reaction tolerated various alkyl and aryl aldehydes and dialkyl ketones, irrespective of their

New efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines through a Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution sequence

• Long Zhao,
• Mao-Lin Yang,
• Min Liu and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2022, 18, 286–292, doi:10.3762/bjoc.18.32

• of their derivatives [12][13][14][15][16][17][18][19][20][21][22]. For example (Scheme 1), a one-pot Tf2O-mediated assembly of amides, amines, and ketones provided 3,4-dihydroquinazolines in good yields via successive triflic anhydride-mediated amide dehydration, ketimine addition, and Pictet

Iridium-catalyzed hydroacylation reactions of C1-substituted oxabenzonorbornadienes with salicylaldehyde: an experimental and computational study

• Angel Ho,
• Austin Pounder,
• Krish Valluru,
• Leanne D. Chen and
• William Tam

Beilstein J. Org. Chem. 2022, 18, 251–261, doi:10.3762/bjoc.18.30

• bonds [6][7][8][9][10][11][12][13]. Hydroacylation reactions, the formal addition of an aldehyde C–H bond across a C–C π-system, has emerged as a powerful, and highly atom-economic approach to synthesize ketones. As such, C–H functionalizations are inherently both environmentally benign and economically

New advances in asymmetric organocatalysis

• Radovan Šebesta

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

• early to stimulate greater developments. Things started to change in the late 1990s when short-chain peptides [3], carbohydrate-based ketones [4][5], and thioureas [6] were shown to catalyze enantioselective transformations. The real breakthrough came in the year 2000 when two teams independently

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• others [12]. The α-epoxyketone is isosteric to an acetylated lysine residue, which makes it a mimic of HDAC’s natural substrate [10]. Although α-epoxyketones and hydroxamic acids show high affinities towards Zn2+, other chelating groups are also found in natural products (Figure 2) including ketones

• (apicidin [19], microsporin A [20]), carboxylic acids (azumamides [21]), α-hydroxy ketones (FR235222 [22]) or thioesters (largazole [23]). These cyclopeptides mainly differ in the amino acid sequence of the peptide backbone, which causes selectivity towards the different HDAC isoforms. In fact, many

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• intracellular ROS and includes inhibition of tubulin polymerization (Scheme 9). Semicarbazides and thiosemicarbazides are substances used to identify aldehydes and ketones, are very versatile in the synthesis of heterocycles, and have several applications in the preparation of important drugs. Nucleophilic