Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• . Although the Vilsmeier–Haack reaction [1] or amide reduction with LiAlH4 are textbook examples that easily come to mind, there are not many other methods available. Simple alkyl and aryl amides, unlike other carbonyl compounds, typically do not undergo direct addition by a nucleophile, including active

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• desired products 267 or 268 in moderate yields and enantioselectivities (3 examples, up to 75:25 er for 267 and 2 examples, up to 68:32 er for 268). Lewis acid catalysis Lewis acids have been known for decades to activate carbonyl compounds through the formation of coordination complexes that increases

Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes

• Thomas Schneider,
• Michael Keim,
• Bianca Seitz and
• Gerhard Maas

Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173

• reaction of trifluoroacetaldehyde hemiaminals with enolizable carbonyl compounds in the presence of a strong base [23], the reaction of aldiminium salts with (trifluoromethyl)trimethylsilane/Lewis base [24], and the preparation of secondary α-(trifluoromethyl)propargylamines from imines CF3CH=NR and

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

• Yuqing Wang,
• Gaigai Wang,
• Anatoly A. Peshkov,
• Ruwei Yao,
• Muhammad Hasan,
• Manzoor Zaman,
• Chao Liu,
• Stepan Kashtanov,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163

• carbonyl compounds promoted by cinchona alkaloid derivatives developed independently by Shibata, Takeuchi and co-workers [65][66] and by the group of Cahard [67][68][69][70]. The method proved to be applicable to a broad range of substrates under a variety of conditions [71][72][73][74][75][76][77][78] and

Fluorohydration of alkynes via I(I)/I(III) catalysis

• Jessica Neufeld,
• Constantin G. Daniliuc and
• Ryan Gilmour

Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135

• ]. Remarkable advances in the direct fluorination (F2/N2) of carbonyl compounds by Sandford and co-workers [14][15] are noteworthy in this regard, and mitigate the expense and poor atom economy associated with stoichiometric approaches. Moreover, this substructure provides a versatile entry point for subsequent

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• degree of crosslinking, thus influencing the final properties [1][2]. Among the various bifunctional compounds that could be used as crosslinking agents, active carbonyl compounds, such as carbonyldiimidazole (CDI) and diphenyl carbonate have given interesting results in the last 20 years. The produced

An overview on disulfide-catalyzed and -cocatalyzed photoreactions

• Yeersen Patehebieke

Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118

• also catalyze the formation of four-membered ring intermediates between double or triple bonds and oxygen, and thus converting unsaturated hydrocarbons to carbonyl compounds. Regarding the oxidation of alkynes, Wang reported a method for preparing diaryl-1,2-diketones from diarylalkynes in the presence

• ). One exceptional decrease in the yield of the hydroxylation product (13–33%) occurred when β-keto esters with methoxy groups on the phenyl ring were used, but the hydroxymethylation yield was just undulated slightly. Other carbonyl compounds, 1,3-diones, and functionalized five-, six-, and seven

• disulfide-catalyzed isomerization of allyl alcohols to carbonyl compounds under high-pressure mercury lamp irradiation (λ > 300 nm) at room temperature. The yield of the reaction reached up to 91% (Scheme 23) [30]. Using the water-soluble dendrimer disulfide, the photoinduced isomerization in water was also

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• as scavengers of C-centered radicals [9] and selective oxidation organocatalysts (for example, in the oxidation of alcohols to the corresponding carbonyl compounds [10][11]). Recently, highly reactive imidoxyl radicals (Figure 1, II) have found a wide application in the processes of hydrogen atom

• the decomposition of iminoxyl radicals 2 generated from oximes 1 under the action of Ag2O [53] were studied by K. U. Ingold et al. (Figure 2). In most cases, the reaction was accompanied by the release of N2 and N2O, as well as the corresponding carbonyl compounds (3a–c). Dimerization of iminoxyl

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• compared to other methods for radical generation [56]. Within this field, organic dyes can act as competent photocatalysts for direct HAT processes. Specifically, upon light excitation, photoactive carbonyl compounds, such as benzophenone and its derivatives, reach an electronically excited triplet state

• , oxylacyl, and carbamoyl radicals and their analogues The photocatalyzed generation of acyl radicals is of great interest as they are precursors for the synthesis of diverse carbonyl compounds [88]. The acyl radical is generally considered as a nucleophilic radical and reacts rapidly with electron-poor π

• radicals Thiyl (sulfenyl) radicals Thiyl radicals are common, versatile, strong nucleophilic radicals. They are efficient at performing atom abstractions, in particular with H-atoms, adding to π-systems and electrophiles, such as carbonyl compounds [166]. They can be generated from the UV irradiation of

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

• capable to induce other types of reactions, such as hydrogen atom abstraction (HAT) processes or triplet state energy transfer processes (EnT). Carbonyl compounds, especially diaryl ketones, have shown great potential as far as their catalytic scope is concerned. Benzophenone or acetophenone (64) and

• examples where aldehydes were employed as photoinitiators in organic synthesis. Review Photophysical properties of carbonyl compounds The interest in the interaction of aldehydes with light to promote reactions can be traced many years back. In 1966, Davies and co-worker studied the energy transfer from

• state Τ2 (π,π*), which will subsequently drive them to a lower triplet state T1 (n,π*), with the latter one being responsible for the specific reactivity of the carbonyl compounds [21][22]. During the photoexcitation of a carbonyl compound, and after they reach the T2 excited triplet state, there are

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

• bond formation Organoboron compounds are widely used in C–C and C–X (X = N, O) bond constructions. Straightforward methods for their synthesis involve the copper-catalyzed addition of organoboron compounds to alkynes, alkenes, and unsaturated carbonyl compounds, as well as the nucleophilic borylation

• B2pin2 in moderate to excellent yields [127]. 2.3 β-Borylation of α,β-unsaturated compounds The use of an inexpensive transition metal like copper as catalyst is attractive for β-borylations of α,β-unsaturated carbonyl compounds, that can then be further functionalized. In 2000, an initial report

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• work of Stryker and co-workers on triphenylphosphine-stabilized copper hydride complexes [1][2], copper hydrides have been widely used for conjugate reductions of α,β-unsaturated carbonyl compounds [3]. Especially a chiral copper catalyst combined with a stoichiometric amount of a silane reagent, which

• generated copper hydride in situ, has successfully been utilized for enantioselective reactions with β,β-disubstituted α,β-unsaturated carbonyl compounds [4][5][6][7][8][9][10][11]. The pioneering work of Buchwald and co-workers on the enantioselective conjugate reduction of α,β-unsaturated esters using a

• chiral p-tol-BINAP/copper catalyst established the excellent utility of chiral bisphosphine ligands for this type of reaction [4]. Surprisingly, however, chiral ligands based on N-heterocyclic carbenes (NHCs) [12] have not been applied to the conjugate reduction of α,β-unsaturated carbonyl compounds

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• )-one [29] derivatives, various enediyne [30][31][32], proflavine [33], N-nitroso carboxamide [34], naphazoline [35] and triazole [36] derivatives, azido carbonyl compounds [37] and N,O-diacyl-4-benzoyl-N-phenylhydroxylamines [38]. O-Acyl amidoximes, ketoximes and aldoximes (I, II and III, respectively

Copper-promoted/copper-catalyzed trifluoromethylselenolation reactions

• Clément Ghiazza and
• Anis Tlili

Beilstein J. Org. Chem. 2020, 16, 305–316, doi:10.3762/bjoc.16.30

• same group studied the direct trifluoromethylselenolation of α-brominated unsaturated carbonyl compounds with [(bpy)CuSeCF3]2 and CsF as the base (Scheme 5, top) [21]. The products were obtained with good yields as a mixture of E/Z isomers. The authors postulated the formation of a copper(III) complex

• ) bromide. The same group also reported the trifluoromethylselenolation of β-brominated unsaturated carbonyl compounds under base-free conditions (Scheme 5, bottom) [22]. Good to excellent yields were obtained for the products. The authors demonstrated that no major alterations were observed in the presence

• carbonyl compounds with [(bpy)CuSeCF3]2 by the group of Weng. Trifluoromethylselenolation of α,β-unsaturated ketones with [(bpy)CuSeCF3]2 by the group of Weng. Trifluoromethylselenolation of acid chlorides with [(bpy)CuSeCF3]2 by the group of Weng. Synthesis of 2-trifluoromethylselenylated benzofused

Ultrasonic-assisted unusual four-component synthesis of 7-azolylamino-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines

• Yana I. Sakhno,
• Maryna V. Murlykina,
• Oleksandr I. Zbruyev,
• Anton V. Kozyryev,
• Svetlana V. Shishkina,
• Dmytro Sysoiev,
• Vladimir I. Musatov,
• Sergey M. Desenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2020, 16, 281–289, doi:10.3762/bjoc.16.27

• approaches were described for the synthesis of 7-hydroxytetrahydroazolopyrimidines by the reaction of aminoazoles, aromatic aldehydes, and some carbonyl compounds (Scheme 1, IV and Scheme 2, VI and VIII) [4][5][16][17][18][19][20][21][22][23]. Oxygen-bridged tetrahydroazolopyrimidines III were also obtained

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• ; synthesis; Introduction The propargylation of carbonyl compounds is widely used in the synthesis of biologically active natural products [1]. Some examples can be found in the synthesis of histrionicotoxin [2], rhizopodin [3], bafilomycin [4], bryostatin [5], vancosamine [6] and macrolactin A [7]. Although

• there are several stereoselective methods described for the reaction of propargyl or allenyl organometallics with carbonyl compounds [8][9][10][11][12][13][14], the control of the regioselectivity is still a major concern. This is mainly due to the metallotropic rearrangement of propargyl and allenyl

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• following three categories: (i) by Wittig or Doebner reaction of indoles bearing a 3-aldehyde group; (ii) by 1,4- or 1,2-addition of α,β-enones or carbonyl compounds, followed by oxidation or elimination, respectively; (iii) by Pd-catalysed oxidative coupling of indoles with activated alkenes. Several

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• ) [23]. In the second report, the same electrode was applied for the asymmetric reduction of prochiral carbonyl compounds 10a and 12a, oximes 14 and gem-dibromo compounds 16 (Scheme 4). Among all of these the highest optical yield (16.6%) was obtained in the reduction of gem-dibromide substrates 16 to

• method for the enantioselective synthesis of 4,5,5-trisubstituted γ-butyrolactones 193 using an electroreductive coupling of diaryl ketones 191 with α,β-unsaturated carbonyl compounds 190 bearing chiral auxiliaries derived from imidazolidin-2-one and oxazolidine-2-ones (Scheme 60). Compound 191 underwent

• modified graphite cathode. Asymmetric hydrogenation of ketones using Raney nickel powder electrodes modified with optically active tartaric acid. Asymmetric reduction of prochiral activated olefins with a poly-ʟ-valine-coated graphite cathode. Asymmetric reduction of prochiral carbonyl compounds, oximes

Unexpected one-pot formation of the 1H-6a,8a-epiminotricyclopenta[a,c,e][8]annulene system from cyclopentanone, ammonia and dimethyl fumarate. Synthesis of highly strained polycyclic nitroxide and EPR study

• Sergey A. Dobrynin,
• Igor A. Kirilyuk,
• Yuri V. Gatilov,
• Andrey A. Kuzhelev,
• Olesya A. Krumkacheva,
• Matvey V. Fedin,
• Michael K. Bowman and
• Elena G. Bagryanskaya

Beilstein J. Org. Chem. 2019, 15, 2664–2670, doi:10.3762/bjoc.15.259

• carbonyl compounds for the synthesis of heterocyclic compounds has been repeatedly demonstrated [2][3]. We recently used a domino reaction of amino acid, ketone and dimethyl fumarate for the one-pot synthesis of a substituted pyrrolidine, which then was converted into a reduction-resistant pyrrolidine

1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds

• Vito A. Fiore,
• Chiara Freisler and
• Gerhard Maas

Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253

• -catalyzed reactions of acetylenic ketones and esters with pinacolborane have been discussed [7][8]. The Michael addition of PPh3 at acetylenic carbonyl compounds generates phosphonium/vinyl anion intermediates which have been trapped with CH-, NH-, OH- and SH-acids [5]. In this manner, the 1:1:1 reaction of

α,ß-Didehydrosuberoylanilide hydroxamic acid (DDSAHA) as precursor and possible analogue of the anticancer drug SAHA

• Shital K. Chattopadhyay,
• Subhankar Ghosh,
• Sarita Sarkar and
• Kakali Bhadra

Beilstein J. Org. Chem. 2019, 15, 2524–2533, doi:10.3762/bjoc.15.245

• reaction in the presence of Hoveyda-Grubbs 2nd generation catalyst (HG-II, 9b, 2 mol %) in refluxing DCM was found to be much faster and better yielding (77%). The product 10a was obtained as a single geometric isomer identified as E. It may be mentioned that CM with other unsaturated carbonyl compounds

In water multicomponent synthesis of low-molecular-mass 4,7-dihydrotetrazolo[1,5-a]pyrimidines

• Irina G. Tkachenko,
• Sergey A. Komykhov,
• Vladimir I. Musatov,
• Svitlana V. Shishkina,
• Viktoriya V. Dyakonenko,
• Vladimir N. Shvets,
• Mikhail V. Diachkov,
• Valentyn A. Chebanov and
• Sergey M. Desenko

Beilstein J. Org. Chem. 2019, 15, 2390–2397, doi:10.3762/bjoc.15.231

• starting material and subsequent dihydropyrimidine ring formation. The first approach [6][7] represents a two-component cyclocondensation of 5-aminotetrazole (1) as binucleophilic component and bielectrophilic α,β-unsaturated carbonyl compounds 2 (Scheme 1, reaction 1). The second method [8][9][10][11][12

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• nucleophilic fluoride source was reported by Doyle and co-worker (Scheme 5) [39]. Herein, the authors utilized a Pd/Cr cocatalytic system to generate the allylic fluorides with high regioselectivity (branched > linear). Alkyl fluorination of acidic carbonyl compounds and other compounds: In 2012, the group of

• achieved using Et3N·3HF as the fluorine source with a high catalyst loading (20–30 mol %) affording the products in 45–92% yield [70]. The heteroatom-containing functional group (R1) is necessary for good reactivity and regioselectivity. α-Fluorination of acidic carbonyl compounds: In 2011, Shibatomi and

• stereocontrolled acrylic allylic fluorides. Fluorination of acidic carbonyl compounds: In 2010, Itoh and co-workers [96] demonstrated the asymmetric fluorination of cyclic and acyclic β-ketoesters by using a catalytic amount of Co(acac)2 with (R,R)-Jacobsen’s salen ligand (Scheme 48). The α-fluorinated products

α-Photooxygenation of chiral aldehydes with singlet oxygen

• Dominika J. Walaszek,
• Magdalena Jawiczuk,
• Jakub Durka,
• Olga Drapała and
• Dorota Gryko

Beilstein J. Org. Chem. 2019, 15, 2076–2084, doi:10.3762/bjoc.15.205

• dichroism (ECD) and TD-DFT methods. Keywords: 1,2-diols; ECD; enamines; organocatalysis; porphyrins; silyl ethers of diarylprolinols; singlet oxygen; Introduction Carbonyl compounds are one of the most important building blocks in organic synthesis. As a consequence, there is a constant need for new

• ) or a chiral auxiliary (i.e., oxazolidinone) into the substrate structure is required for highly stereoselective reactions [20][21][22]. ‘One-pot’ photochemical α,β-functionalization of cinnamaldehyde Over the last few years, photochemical methods for asymmetric functionalisation of carbonyl compounds

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

• Yulia V. Khoroshunova,
• Denis A. Morozov,
• Andrey I. Taratayko,
• Polina D. Gladkikh,
• Yuri I. Glazachev and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

• compound showed a strong absorption band at 1725 cm−1 typical for carbonyl compounds and no absorption in the region 3100–3500 cm−1, suggesting that the hydroxymethyl group was affected in the reaction. The mass spectrum featured the molecular ion [M+] = 196.1335 corresponding to the molecular formula

• C11H18NO2, which matches element analysis data. These results allowed us to assign the structure 15 to this nitroxide. Indeed, oxidation of amines with peracids is known to proceed via oxoammonium cation formation [17][18], and the latter can oxidize alcohols to carbonyl compounds [19]. The close proximity