1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• aldehydes or ketones (mainly formaldehyde) with ammonia or aliphatic amines and CH-acidic carbonyl compounds, known as the Mannich reaction, plays an important role in organic synthesis, despite some limitations of this reaction. α-Amidoalkylation reactions are considered an important extension of the

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• (Scheme 1) [20]. A hydroxy group neighbouring an alkynyl substituent, under treatment with acids, normally leads to Rupe and Meyer–Schuster rearrangements, forming unsaturated carbonyl compounds. This was indeed observed in camphor-derived bicyclic alcohols containing a single ethinyl group [21][22

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

• products and pharmaceuticals, and α-acetoxyaryl ketones are widely used as synthetic intermediates [1][2][3][4][5]. Traditional methods for the preparation of α-acyloxy ketones focus on the substitution reactions of α-halo carbonyl compounds with alkaline carboxylates or carboxylic acids [6][7], and

• transition-metal-catalyzed direct oxidative coupling reactions of carbonyl compounds with carboxylic acids (or their surrogates) [8][9]. Recently, robust approaches using organohypervalent iodine reagents and peroxide-mediated oxidative coupling have been developed [10][11]. Although impressive progress has

Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents

• Josef Jansa,
• Ramona Schmidt,
• Ashenafi Damtew Mamuye,
• Laura Castoldi,
• Alexander Roller,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2017, 13, 895–902, doi:10.3762/bjoc.13.90

• most common strategies employ reactions of 1,3-dicarbonyl compounds or α,β-unsaturated carbonyl compounds with substituted hydrazines [4][6][19]. To overcome the drawbacks of this method, namely insufficient regioselectivity [20], other accesses such as, for instance, regioselective metalations of N

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• carbonyl compounds could successfully generate an enamine or an enolate, and these species react as dipolarophiles with organic azides in organocatalyzed 1,3-dipolar cycloadditions. Our research group has demonstrated β-enamine–azide cycloaddition reactions for the synthesis of selenium-functionalized

Isoxazole derivatives as new nitric oxide elicitors in plants

• Anca Oancea,
• Emilian Georgescu,
• Florentina Georgescu,
• Alina Nicolescu,
• Elena Iulia Oprita,
• Catalina Tudora,
• Lucian Vladulescu,
• Marius-Constantin Vladulescu,
• Florin Oancea and
• Calin Deleanu

Beilstein J. Org. Chem. 2017, 13, 659–664, doi:10.3762/bjoc.13.65

• synthetic approaches towards the isoxazole core include the reactions of hydroxylamine with aryl-β-diketones [20], α,β-unsaturated carbonyl compounds [21], or α,β-unsaturated nitriles [22], and 1,3-dipolar cycloaddition reactions between alkenes or alkynes and nitrile oxides [23][24][25]. Nitrile oxides are

Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

• Jan Szabo,
• Julian Greiner and
• Gerhard Maas

Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57

• , triaminoguanidinium salts or the neutral triaminoguanidine have been reacted with carbonyl compounds. Reactions with aldehydes [3][4][5][6][7] or ketones [8][9][10] yielded the corresponding tris(iminyl)guanidines; cyclocondensation of pentane-2,4-dione at one hydrazinyl branch of TAG-Cl afforded a pyrazole which

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• -Haloalkyllithiums are a useful class of organometallic reagents widely employed in synthetic chemistry. In fact, they allow the direct homologation of carbonyl compounds and imines leading to β-halo-alcohols and amines that are useful building blocks [29][30][31]. This work represents a remarkable example of flash

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• 5- (section 1), 6- (section 2) and simultaneous formation of 5- and 6-membered rings of 1-indanones (section 3) as well as functionalization of 1-indanones or related compounds (section 4). Review 1 Construction of the 5-membered ring 1.1 From carbonyl compounds 1.1.1 From carboxylic acids: The

Efficient access to β-vinylporphyrin derivatives via palladium cross coupling of β-bromoporphyrins with N-tosylhydrazones

• Vinicius R. Campos,
• Ana T. P. C. Gomes,
• Anna C. Cunha,
• Maria da Graça P. M. S. Neves,
• Vitor F. Ferreira and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2017, 13, 195–202, doi:10.3762/bjoc.13.22

• features – stoichiometric organometallic reagents are not required for the coupling reaction and di- and trisubstituted olefins can be prepared with high stereoselectivity. In fact, N-tosylhydrazones used in this methodology can be easily prepared from carbonyl compounds (Scheme 1), as it has been well

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• bond-donor activation of α,β-unsaturated carbonyl compounds in the [2 + 4] cycloaddition reaction of MVK and cyclopentadiene [88]. Halogen bond donor activation of imines in the [2 + 4] cycloaddition reaction of imine and Danishefsky’s diene [90]. Transfer hydrogenation catalyzed by a chiral halogen

Chromium(II)-catalyzed enantioselective arylation of ketones

• Gang Wang,
• Shutao Sun,
• Ying Mao,
• Zhiyu Xie and
• Lei Liu

Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275

• /bjoc.12.275 Abstract The chromium-catalyzed enantioselective addition of carbo halides to carbonyl compounds is an important transformation in organic synthesis. However, the corresponding catalytic enantioselective arylation of ketones has not been reported to date. Herein, we report the first Cr

• pharmaceutical industry. The chromium (Cr)-catalyzed enantioselective addition of carbo halides to carbonyl compounds is one of the most reliable methods in organic chemistry for chemoselective and structurally diverse synthesis [1][2][3][4][5][6][7][8][9]. To date, the Cr-catalyzed enantioselective carbonyl

• pharmaceutical study, finally leading to the discovery of the anticancer drug Eribulin [31][32][33][34][35]. However, to our knowledge, the Cr-catalyzed enantioselective arylation of carbonyl compounds has rarely been explored. On the other hand, most of the reactions focused on aldehyde components, while

Electron-transfer-initiated benzoin- and Stetter-like reactions in packed-bed reactors for process intensification

• Anna Zaghi,
• Daniele Ragno,
• Graziano Di Carmine,
• Carmela De Risi,
• Olga Bortolini,
• Pier Paolo Giovannini,
• Giancarlo Fantin and
• Alessandro Massi

Beilstein J. Org. Chem. 2016, 12, 2719–2730, doi:10.3762/bjoc.12.268

• ). Keywords: C–C coupling; continuos-flow; diketone; electron-transfer; umpolung; Introduction The polarity reversal (umpolung) of carbonyl compounds by N-heterocyclic carbene (NHC) or cyanide catalysis represents a straightforward strategy for the synthesis of valuable molecules such as, among the many

Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

• Artem N. Semakin,
• Aleksandr O. Kokuev,
• Yulia V. Nelyubina,
• Alexey Yu. Sukhorukov,
• Petr A. Zhmurov,
• Sema L. Ioffe and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2016, 12, 2471–2477, doi:10.3762/bjoc.12.241

• -substituted hydrazones 1 were prepared from the corresponding carbonyl compounds and acylhydrazines or carbazates to study the reaction with amines (Scheme 2, for details see Supporting Information File 1). Acetic acid was added as catalyst and for suppression of the side reaction of the formed α-halogen

β-Amino functionalization of cinnamic Weinreb amides in ionic liquid

• Yi-Ning Wang,
• Guo-Xiang Sun and
• Gang Qi

Beilstein J. Org. Chem. 2016, 12, 2372–2377, doi:10.3762/bjoc.12.231

• ; ionic liquid; Weinreb amides; Introduction Unlike N-protected α-amino carbonyl compounds, their analogues, the β-amino carbonyl compounds, have drawn relatively little attention. However, the β-amino carbonyl moieties are not only found in natural products [1][2][3], e.g., in the side chain of Taxol

• towards the preparation of β-amino carbonyl compounds is the Mannich reaction [8][9]. However, there are few reported methods specifically focused on this target, which include oxidation of γ-amino alcohols [10], hydrolysis of 1,3-oxazines [11], rearrangement of 2,3-aziridinio alcohols [12], etc. N

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

• Martin Obst and
• Burkhard König

Beilstein J. Org. Chem. 2016, 12, 2358–2363, doi:10.3762/bjoc.12.229

• reaction mixture. The corresponding carbonyl compounds were obtained in moderate to good yields. Keywords: benzylic alcohol; oxidation; photocatalysis; solvent free; visible light; Introduction According to a classification made by Wilhelm Ostwald, one of the pioneers in the field of physical chemistry

• photocatalyst has been reported yet. In this work, we present a novel milling apparatus, which we developed especially for the conversion of solid substrates. Applying this apparatus, the solvent-free oxidation of various benzylic alcohols to their corresponding carbonyl compounds using riboflavin tetraacetate

• catalyst was reported [15], which was also used for cyclization to form coumarins [16]. In this work, we focus on benzylic alcohols as substrates since their oxidation to the corresponding carbonyl compounds can be simply performed in acetonitrile/water mixtures. Thus, they are suitable model substrates

Diastereoselective synthesis of 3,4-dihydro-2H-pyran-4-carboxamides through an unusual regiospecific quasi-hydrolysis of a cyano group

• Mikhail Yu. Ievlev,
• Oleg V. Ershov,
• Mikhail Yu. Belikov,
• Angelina G. Milovidova,
• Viktor A. Tafeenko and
• Oleg E. Nasakin

Beilstein J. Org. Chem. 2016, 12, 2093–2098, doi:10.3762/bjoc.12.198

• convenient methods for the construction of 3,4-dihydro-2H-pyrans are based on the interaction between ylidene derivatives of methylene-active compounds and β-oxo derivatives of acids or ketones [9][10][11], and also on the reactions of phenols with carbonyl compounds [12]. An interesting example that had

Bridgehead vicinal diallylation of norbornene derivatives and extension to propellane derivatives via ring-closing metathesis

• Sambasivarao Kotha and
• Rama Gunta

Beilstein J. Org. Chem. 2016, 12, 1877–1883, doi:10.3762/bjoc.12.177

• stereocontrolled manner in a single step is not a trivial exercise. Generally, it was accomplished by radical three-component coupling reactions or Michael-type additions of organocopper reagents starting with conjugated carbonyl compounds [33][34]. But, the resulting alkyl groups are in trans orientation. Our

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

• search for new synthetic methods for peroxides starting from carbonyl compounds, hydrogen peroxide, and hydroperoxides [121][122][123][124][125][126][127][128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148][149][150][151][152][153][154][155][156][157

• ]. Since that time, this reaction has shown to be of general applicability and it has gained wide application for the oxidation of carbonyl compounds of different structures. In this reaction, cyclic ketones are transformed into lactones, acyclic ketones, into esters and aldehydes into carboxylic acids

Rh-Catalyzed reductive Mannich-type reaction and its application towards the synthesis of (±)-ezetimibe

• Motoyuki Isoda,
• Kazuyuki Sato,
• Yurika Kunugi,
• Satsuki Tokonishi,
• Atsushi Tarui,
• Masaaki Omote,
• Hideki Minami and
• Akira Ando

Beilstein J. Org. Chem. 2016, 12, 1608–1615, doi:10.3762/bjoc.12.157

• Mannich-type reactions have been reported to give β-amino esters and/or β-lactams by using metal enolates [10][11][12][13][14][15][16][17]. In contrast, most of reductive Mannich-type reactions using imines and α,β-unsaturated carbonyl compounds gave β-amino esters, but there are only a few reports for a

• results using similar conditions did not give the corresponding products such as β-propiolactones. It is well known that the substituents on the α- or β-position of α,β-unsaturated carbonyl compounds affect the yields and stereoselectivities [37]. A rhodium–hydride complex derived from [RhCl(cod)]2 seems

On the cause of low thermal stability of ethyl halodiazoacetates

• Magnus Mortén,
• Martin Hennum and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2016, 12, 1590–1597, doi:10.3762/bjoc.12.155

• decompose within hours at room temperature. They are inherently unstable to acid and the diazo carbon has a significant nucleophilic character. Even though a complete understanding is lacking for the thermal decomposition of aliphatic diazo compounds, the increased stability of diazo carbonyl compounds

Cp₂TiCl/D₂O/Mn, a formidable reagent for the deuteration of organic compounds

• Antonio Rosales and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2016, 12, 1585–1589, doi:10.3762/bjoc.12.154

• ] or activated halides [30] and Cp2TiCl/Mn), to intermediate titanaoxiranes (pathway B) [31][32] (obtained from carbonyl compounds and Cp2TiCl/Mn), and to late transition metals (pathway C) [33] in a process mediated by Cp2TiCl/Mn/H2O or D2O which allows for the reduction of alkenes or alkynes (Scheme

• summary, we presented an overview of the Cp2TiCl/D2O/Mn combination as an efficient, cheap, selective, and sustainable reagent compatible with different functional groups that mediates the deuteration of organic compounds from epoxides, ozonides, carbonyl compounds, activated halides, alkenes and alkynes

The EIMS fragmentation mechanisms of the sesquiterpenes corvol ethers A and B, epi-cubebol and isodauc-8-en-11-ol

• Patrick Rabe and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2016, 12, 1380–1394, doi:10.3762/bjoc.12.132

• difficult. The profound knowledge about EIMS fragmentation reactions can be used to identify certain structural motifs, e.g., the mass spectra of acyclic carbonyl compounds are often dominated by fragment ions formed via McLafferty rearrangement [4], while cyclohexene derivatives often show major fragment

Synergistic chiral iminium and palladium catalysis: Highly regio- and enantioselective [3 + 2] annulation reaction of 2-vinylcyclopropanes with enals

• Haipan Zhu,
• Peile Du,
• Jianjun Li,
• Ziyang Liao,
• Guohua Liu,
• Hao Li and
• Wei Wang

Beilstein J. Org. Chem. 2016, 12, 1340–1347, doi:10.3762/bjoc.12.127

• ]. However, it is difficult to apply the catalytic system for the regio-controlled reaction with C=C bonds in α,β-unsaturated carbonyl compounds, particularly enals. The highly active aldehyde functionality reacts more favorably with the D–A cyclopropane resulting 1,3-dipoles, as elegantly demonstrated by

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• carbonyl compounds such as β-diketones, β-keto thioesters, acetoacetamides and nitroacetone have been shown to participate in the classical Biginelli reaction [25], β-ketophosphonates 6 were found to be unreactive in similar conditions [26]. However, Yuan et al. developed a modified Biginelli condensation