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

Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• a mechanochemical process. Keywords: AZADO; Ertalyte®; green chemistry; mechanochemistry; NaOCl·5H2O; selective oxidation; TEMPO; Introduction The conversion of primary and secondary alcohols to the corresponding carbonyl compounds (aldehydes and ketones, respectively) is of such importance in

• to industrial settings. The proposed mechanism for the TEMPO-based oxidative conversion of primary and secondary alcohols to the corresponding carbonyl compounds is described in Scheme 7 and shares similarities with that postulated in other previous studies in solution. In general, NaOCl works as a

• the atom efficiency [4][5]. The discovery of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, commonly known as TEMPO by Lebedev and Kazarnowskii in 1960 has been hailed as a significant breakthrough in the field of redox reactions, allowing the fast and selective oxidation of alcohols to the related carbonyl

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

Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

• Qichao Zhang,
• Jian Lv and
• Sanzhong Luo

Beilstein J. Org. Chem. 2019, 15, 1304–1312, doi:10.3762/bjoc.15.129

• , could promote the Diels–Alder reaction with anthracenes and various unsaturated carbonyl compounds under mild conditions [13]. The use of latent carbocation catalysis with TP was examined in order to achieve enantioselective control. To our delight, TP catalyzed the asymmetric reaction affording

Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination

• Thomas Di Nardo and
• Audrey Moores

Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119

• stainless steel ones, since the latter caused the reactive mixture to adhere to the jars, which was not the case of the former. In another example, for the metal-free transfer hydrogenation of carbonyl compounds, PTFE was used instead of steel to eliminate the possibility of catalysis from the milling media

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

• Victoria V. Lipson,
• Tetiana L. Pavlovska,
• Nataliya V. Svetlichnaya,
• Anna A. Poryvai,
• Nikolay Yu. Gorobets,
• Erik V. Van der Eycken,
• Irina S. Konovalova,
• Svetlana V. Shiskina,
• Alexander V. Borisov,
• Vladimir I. Musatov and
• Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

• -bielectrophiles or their synthetic precursors in the case of three-component reactions between these amines, carbonyl compounds and CH acids. Previously, an unusual direction of the three-component reaction between 2-aminoimidazoles, aldehydes and 5,5-dimethyl-1,3-cyclohexanedione has led to the formation of the

Catalytic asymmetric oxo-Diels–Alder reactions with chiral atropisomeric biphenyl diols

• Chi-Tung Yeung,
• Wesley Ting Kwok Chan,
• Wai-Sum Lo,
• Ga-Lai Law and
• Wing-Tak Wong

Beilstein J. Org. Chem. 2019, 15, 955–962, doi:10.3762/bjoc.15.92

• alkene); it is called a hetero-Diels–Alder (HDA) reaction when one or more heteroatoms (most often oxygen or nitrogen) are present among the reactants, such as the use of carbonyl compounds or imines as dienophiles [1][2][3][4][5]. An asymmetric HDA reaction is capable of introducing up to four

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• obtained β-ketoenamides are alkenes with a remarkable assembly of functional groups: they are enamides, enol ethers and α,β-unsaturated carbonyl compounds at the same time. In addition, their methyl ketone subunit is required for some of the subsequent transformations, e.g., the synthesis of pyridin-4-ols

Asymmetric synthesis of a high added value chiral amine using immobilized ω-transaminases

• Antonella Petri,
• Valeria Colonna and
• Oreste Piccolo

Beilstein J. Org. Chem. 2019, 15, 60–66, doi:10.3762/bjoc.15.6

• carbonyl compounds. In a kinetic resolution, a maximum yield of 50% of the product can be obtained. Moreover, high quantities of the co-product might complicate the product separation and the recovery of the chiral amine. Thus, the asymmetric synthesis is generally preferable because a theoretically 100

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• between ketones and aryl-substituted 1,2,4,5-tetrazines which leads to functionalized pyridazines. They also postulated a mechanism (Scheme 1) for the reaction [51]. Based on the knowledge that secondary amines catalyze the formation of enamines from ketones and other carbonyl compounds [33], an initial

A convenient and practical synthesis of β-diketones bearing linear perfluorinated alkyl groups and a 2-thienyl moiety

• Ilya V. Taydakov,
• Yuliya M. Kreshchenova and
• Ekaterina P. Dolotova

Beilstein J. Org. Chem. 2018, 14, 3106–3111, doi:10.3762/bjoc.14.290

• commercial batches of NaOMe or NaOEt, along with samples freshly prepared in the laboratory. In all the experiments, anhydrous Et2O was used as the solvent and the initial concentration of carbonyl compounds was 0.2 mol/L. Methyl heptafluorobutanoate (2) was chosen as the ester because the corresponding β

• course of the reaction but significantly facilitates the purification process. The best results were obtained if THF solution of carbonyl compounds was slowly added dropwise to a suspension of NaH in THF, while the temperature was maintained below +5 °C. Upon completion of the condensation, the reaction

Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion

• Rudolf Knorr and
• Barbara Schmidt

Beilstein J. Org. Chem. 2018, 14, 3018–3024, doi:10.3762/bjoc.14.281

• -tetramethylindan-2-ylidene)acetonitriles added reversibly to three small aldehydes and two bulky ketones at room temperature. Experimental conditions were determined for transfer of the nucleofugal title carbanion unit between different carbonyl compounds. These readily occurring retro-additions via C–C(O) bond

• trapped by proton sources such as DMSO or unconsumed 7 to produce 1. As a consequence, the general procedure (GP) of adding carbonyl compounds to deprotonated 1 commends to use an acidic work-up and a strict exclusion of bases that are stronger than diluted aqueous NaHCO3. Benzaldehyde (5) and

• . Alternatively, carbonyl additions to 2Li might be generally retarded (relative to protonations) on account of the clustered [4] ground state structure of 2Li in solution. Electrophilic cations (Li+ or K+) are not necessary (albeit perhaps helpful) for the addition of the carbanion unit of 2Li or 2K to carbonyl

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• these catalysts for extensive reactions, including the synthesis of bis(indolyl)methane derivatives, β-amino carbonyl compounds, 14H-dibenzo[a,j]xanthene derivatives, 1,8-dioxodecahydroacridine derivatives, xanthene derivatives, pyrimido[4,5-b]quinoline derivatives, spiro-isatin derivatives, spiro

• and 37 from active carbonyl compounds (e.g., isatins 32, acenaphthoquinone (33), and aldehydes 38), a variety of C–H activated acids (cyclohexane-1,3-dione (20a), 5,5-dimethylcyclohexane-1,3-dione (20b), 2-naphthol (23), ethyl acetoacetate (34a), 4-hydroxycoumarin (34b), triacetic acid lactone (34c

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• carboxylation of mesityl triflate (5) at 40 °C proceeded successfully, affording 6 in 77% yield (Scheme 6) Carboxylation of α,β-unsaturated nitriles and esters α,β-Unsaturated carbonyl compounds are good substrates for conjugate additions that use a catalytic amount of a metal complex and a stoichiometric

Practical tetrafluoroethylene fragment installation through a coupling reaction of (1,1,2,2-tetrafluorobut-3-en-1-yl)zinc bromide with various electrophiles

• Ken Tamamoto,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 2375–2383, doi:10.3762/bjoc.14.213

• apparatus [24] or reductive couplings with various carbonyl compounds [25], leading to good yields of versatile CF2CF2-containing substances. However, many obstacles to practical synthesis remain, e.g., the use of 1,2-dibromotetrafluoroethane (Halon-2402) with ozone depletion and global warming potentials

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• process [92]. As the cyclization of 1,n-enynes with organometallics is well-known, the addition of an inert C–H bond to 1,n-enynes further enhances the economy of cyclization process. Thus, Cheng and co-workers reported a cobalt-catalyzed hydroarylative cyclization of 1,n-enynes with carbonyl compounds 55

• . Co-catalyzed hydroarylative cyclization of enynes with carbonyl compounds. Mechanism for the Co-catalyzed hydroarylative cyclization of enynes with carbonyl compounds. Co-catalyzed addition of 2-arylpyridines to aromatic aldimines. Co-catalyzed addition of 2-arylpyridines to aziridines. Co(III

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• electrochemical synthesis [2], and as mediators of living polymerization [10][11]. In organic synthesis more stable types of N-oxyl radicals can be used as carbon-centered radical scavengers [12], oxidation catalysts, mainly for conversion of alcohols to carbonyl compounds [11][13][14][15][16][17]. Less stable

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• convenience and good stereoselectivity [5][6]. Accordingly, different versions of this reaction have been extensively studied. Notably, the Michael addition reaction of 1,3-dicarbonyl compounds to conjugated nitroalkenes is very important for the synthesis of chiral nitro carbonyl compounds, such as bioactive

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• product of its acetylation Dess–Martin periodinane (DMP) are the most common oxidants used for selective oxidation of alcohols to carbonyl compounds as well as for a variety of other synthetically useful oxidative transformations [10][11]. IBX and DMP are mild oxidants with a relatively low reactivity

• to the respective carbonyl compounds with Oxone® (2KHSO5·KHSO4·K2SO4) in nitromethane, acetonitrile, or ethyl acetate [13]. Recent research has revealed the extreme activity of IBS as a catalyst in numerous other oxidations, such as: the oxidation of benzylic and alkane C–H bonds [14], the oxidation

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

• , α-functionalization of carbonyl compounds, spirocyclizations, as well as functionalization of alkenes and alkynes [10][11][12][13][14][15][16][17]. In recent years, especially the functionalization of alkenes has attracted much attention [18][19][20] and in some cases, hypervalent iodine(III

• -deficient unsaturated carbonyl compounds (Scheme 13). In general, terminal alkenes were found to undergo 1,2-difluorination 42a–c. The reaction of internal alkenes usually afforded the syn-difluorination products 42d and 42e. However, the opposite result was observed in the reaction of the o-nitrostyrene

An amine protecting group deprotectable under nearly neutral oxidative conditions

• Shahien Shahsavari,
• Chase McNamara,
• Mark Sylvester,
• Emily Bromley,
• Savannah Joslin,
• Bao-Yuan Lu and
• Shiyue Fang

Beilstein J. Org. Chem. 2018, 14, 1750–1757, doi:10.3762/bjoc.14.149

• , the dM-Dmoc group is expected to be more stable under nucleophilic conditions, which will allow many transformations including base hydrolysis of esters and amides, hydride reduction of carbonyl compounds, and a wide range of nucleophilic substitution reactions to be carried out without losing the

Visible light-mediated difluoroalkylation of electron-deficient alkenes

• Vyacheslav I. Supranovich,
• Vitalij V. Levin,
• Marina I. Struchkova,
• Jinbo Hu and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2018, 14, 1637–1641, doi:10.3762/bjoc.14.139

• availability issues [25][26][27][28][29]. Recently, we developed a general protocol for the synthesis of iodides 1 from organozinc reagents and a source of difluorocarbene [30][31][32] (Scheme 1). Moreover, it was shown that compounds bearing the CF2I group can be obtained from carbonyl compounds and