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

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• ][10][11][12][13]. Regarding reactions which involve proton transfer events, soft enolization [14][15][16] constitutes an efficient tool for the deprotonation of some carbonyl compounds [17][18]. In these cases, a relatively weak amine is generally used to reversibly deprotonate a relatively acidic

Strecker degradation of amino acids promoted by a camphor-derived sulfonamide

• M. Fernanda N. N. Carvalho,
• M. João Ferreira,
• Ana S. O. Knittel,
• Maria da Conceição Oliveira,
• João Costa Pessoa,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2016, 12, 732–744, doi:10.3762/bjoc.12.73

• of imines with certain carbonyl compounds is the basis for enzymatic transamination and many other reactions [20][21] while the Strecker degradation is one cornerstone in food chemistry [22]. We present here details on the characterization of compound 2, which extends the scope of Strecker

• acid-catalyzed imine formation from amino groups and carbonyl compounds as well as imine hydrolysis can easily occur [25]. The key step in the reaction sequence leading to compound 2, would then be the loss of CO2 by a variant of the Strecker degradation. This step is taken “as granted” and is not

• Supporting Information File 3. From these calculations we can draw the following conclusions: i) imines formed by reaction of amino acids with carbonyl compounds have the tendency to lose CO2 upon deprotonation of the carboxyl group. Without a negative charge at the carboxyl group, decarboxylation is

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• designed and developed, the functionalization of carbonyl compounds via enamine and iminium ion intermediates are the most common [4][5] (Scheme 1). The carbonyl compound condenses with the amino catalyst, to form an iminium ion, subsequent deprotonation leads to the highly nucleophilic enamine. This kind

• efficient ways of constructing six-membered rings. Activation of carbonyl compounds via enamine and iminium intermediates [2]. Electronic and steric interactions present in enamine activation mode [2]. Electrophilic activation of carbonyl compounds by a thiourea moiety. Asymmetric synthesis of dihydro-2H

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

• Laura A. Bryant,
• Rossana Fanelli and
• Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

• set up a 4π-electrocyclization, generating second intermediate 27. Elimination of the tertiary amine then gives γ-methylene cyclopentenone 28. 1,2-Addition reactions Henry reaction The use of cupreine and cupreidine derivatives in the addition of nitroalkanes to carbonyl compounds was first

Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors

• Ming-Liang Zhang,
• Deng-Feng Yue,
• Zhen-Hua Wang,
• Yuan Luo,
• Xiao-Ying Xu,
• Xiao-Mei Zhang and
• Wei-Cheng Yuan

Beilstein J. Org. Chem. 2016, 12, 295–300, doi:10.3762/bjoc.12.31

• amino-alcohols, amino acids and carbonyl compounds [15]. Much attention has been devoted to the development of an efficient catalytic asymmetric version of this reaction from readily accessible nitroalkanes and carbonyl compounds [16], such as aldehydes [17][18][19], α-ketoesters [20], α

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

• Daniel I. Hădărugă,
• Mustafa Ünlüsayin,
• Alexandra T. Gruia,
• Cristina Birău (Mitroi),
• Gerlinde Rusu and
• Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

• intermediates resulting from the oxidation of FAs are monohydroperoxides, hydroperoxy-epidioxides, as well as peroxy-, alkoxy-, and alkyl radicals [16]. Further thermal degradation or fragmentation of these intermediates leads to odor-active carbonyl compounds such as aldehydes, ketones, alcohols and esters

Facile synthesis of 4H-chromene derivatives via base-mediated annulation of ortho-hydroxychalcones and 2-bromoallyl sulfones

• Srinivas Thadkapally,
• Athira C. Kunjachan and
• Rajeev S. Menon

Beilstein J. Org. Chem. 2016, 12, 16–21, doi:10.3762/bjoc.12.3

• ], multicomponent reactions [8], ring-closing metathesis approaches [9][10], tandem reactions of 1,3-dicarbonyl compounds [11][12] and cyclocondenzation reactions of salicylic aldehydes with α,β-unsaturated carbonyl compounds [13][14][15]. The utility of some of these methods are limited by drawbacks such as

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• coordination to the ruthenium atom, and finally, facilitates the initiating process. In the new catalyst 9, which is modified in the NHC ligand, different effects are responsible for its activity. According to Grubbs [31], catalyst 1 is able to react with α,β-unsaturated carbonyl compounds to form an enoic

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

• David Porter,
• Belinda M.-L. Poon and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 2549–2556, doi:10.3762/bjoc.11.275

• context there has been a renewed focus on the chemistry of acylnitroso species in recent times [12][13][14][15], in particular on α-hydroxyamination of carbonyl compounds via nitrosocarbonyl aldol reactions [16][17][18][19][20][21] and allylic hydroxyamination of alkenes via nitroso–ene reactions [22][23

• ) revealed two peaks with equal peak areas (tR = 8.6 and 8.8 minutes); the same peaks in the same ratio were observed using a reference sample of racemic 9. Several groups have recently reported efficient methods for the asymmetric hydroxyamination of carbonyl compounds using acylnitroso species generated in

Efficient synthetic protocols for the preparation of common N-heterocyclic carbene precursors

• Morgan Hans,
• Jan Lorkowski,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2015, 11, 2318–2325, doi:10.3762/bjoc.11.252

• ][23] and organic synthesis [24][25][26]. In particular, they were successfully employed for the umpolung of carbonyl compounds, sometimes in an asymmetric fashion [27][28][29]. Currently, the NHCs most frequently encountered are based on the imidazol-2-ylidene and imidazolin-2-ylidene scaffolds, which

A new approach to ferrocene derived alkenes via copper-catalyzed olefination

• Vasily M. Muzalevskiy,
• Aleksei V. Shastin,
• Alexandra D. Demidovich,
• Namiq G. Shikhaliev,
• Abel M. Magerramov,
• Victor N. Khrustalev,
• Rustem D. Rakhimov,
• Sergey Z. Vatsadze and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2015, 11, 2072–2078, doi:10.3762/bjoc.11.223

• , 28 Vavilov Street, Moscow 119991, Russia 10.3762/bjoc.11.223 Abstract A new approach to ferrocenyl haloalkenes and bis-alkenes was elaborated. The key procedure involves copper catalyzed olefination of N-unsubstituted hydrazones, obtained from ferrocene-containing carbonyl compounds and hydrazine

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• further oxidation. SCPC oxidations that take place with varying success include toluene to benzaldehyde and benzoic acid [25], cyclohexane to cylohexanone [26], benzylic and allylic alcohols to carbonyl compounds [27] and alkene epoxidations [28]. Conventional syntheses of coumarins, which are important

• 64 but a significant quantity of ring opened byproduct was also formed. Carbonyl compounds are also good electron acceptors and so SCPC hydrogenations seemed likely. Actually there is a literature precedent for photocatalytic hydrogenation of acetophenone derivatives with TiO2 [80][81]. We studied a

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• alkenyl chain of sufficient length the [n]paracyclophane 172 was obtained by an intramolecular cyclization (Scheme 27). Alcaide and co-workers [153] have reported the synthesis of different bis(dihydrofuryl)cyclophane scaffolds 179 from carbonyl compounds. 1,4-Bis(3-bromoprop-1-ynyl)benzene (175) was

Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

• Antonio Monopoli,
• Pietro Cotugno,
• Carlo G. Zambonin,
• Francesco Ciminale and
• Angelo Nacci

Beilstein J. Org. Chem. 2015, 11, 994–999, doi:10.3762/bjoc.11.111

• allylation; Introduction The α-allylation of carbonyl compounds is one of the most important reactions in organic chemistry, since it opens the way to the synthesis of a plethora of interesting molecules such as pheromones, perfumes, or bio-active compounds such as prostaglandin E2 or F2α. After the

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• of boron to α,β-unsaturated carbonyl compounds. Enantioenriched organoboron reagents are useful because they can be used in cross-coupling reactions [98][100] or they can be converted into the corresponding alcohol [101] while retaining the stereochemical information. Transition metals such as Cu

• [102][103][104][105][106][107][108][109][110][111][112], Rh [113][114][115], Ni [116][117], Pd [116][118] and Pt [119][120] have all been successfully used to catalyze the 1,4-additon of boron to α,β-unsaturated carbonyl compounds. Of the transition metals mentioned, copper is the most cost-effective

• )diboron to various α,β-unsaturated carbonyl compounds [121]. Use of bisboronic acid and tetrakis(dimethylamino)diboron provides boron sources that are more atom economical than B2pin2. Scheme 11 shows an example of the asymmetric 1,4-borylation where the authors used an α,β-unsaturated amide as the

Ruthenium-catalyzed C–H activation of thioxanthones

• Danny Wagner and
• Stefan Bräse

Beilstein J. Org. Chem. 2015, 11, 431–436, doi:10.3762/bjoc.11.49

• -substituted olefin 4d was also successfully used in this reaction (Table 2, entry 7). The product 1bd is formed in good yield, however, it is prone to hydrolysis thus the isolated yield of the pure product was rather low. In contrast to literature precedence for other carbonyl compounds [19], other olefins

• cleavage catalyzed by hot sulfuric acid. In this case, methylation (Me2SO4, K2CO3) of the hydroxythioxanthones 1c, 1e and 1g provided the required methyl ethers 1d, 1f and 1h, respectively in good yields (80, 85 and 95%), Scheme 1. Ru-catalyzed C–H activation Following the precedence for other carbonyl

• compounds, we used the protocol of Murai et al. [19] to investigate the use of thioxanthones in this C–H-alkylation reaction (Scheme 2). For recent examples and reviews, also for related rhodium-catalyzed systems, see [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. It should be noted that