Symmetry-based approach to oligostilbenoids: Rapid entry to viniferifuran, shoreaphenol, malibatol A, and diptoindonesin G

• Youngeun Jung,
• Dileep Kumar Singh and
• Ikyon Kim

Beilstein J. Org. Chem. 2016, 12, 2689–2693, doi:10.3762/bjoc.12.266

• natural oligostilbenoids guided us to design a modular synthetic approach to these molecules by utilizing a three-step sequence consisting of Sonogashira coupling, iodocyclization, and Suzuki coupling. During our synthesis, the relative reactivities of ester, aldehyde, and alkoxy groups on the same aryl

• , 2, and 3) were readily available from the corresponding C2 symmetric precursors via monoiodination, we decided to evaluate this route. In particular, we wondered what functional group as a G moiety would be appropriate for the successful iodine-mediated cyclization. Ester, aldehyde, and alkoxy

• product which decomposed eventually. On the other hand, 6 was successfully converted to the desired 3-iodobenzofuran 11 in good yield. These results led us conclude that either ester or aldehyde groups perform as better nucleophiles than an alkoxy group in the iodocyclization. Having secured gram

Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: synthesis, characterization and highly selective sensor for Cu²⁺

• Rahman Hosseinzadeh,
• Mohammad Nemati,
• Reza Zadmard and
• Maryam Mohadjerani

Beilstein J. Org. Chem. 2016, 12, 1749–1757, doi:10.3762/bjoc.12.163

• ]arene bearing anthraceneisoxazolymethyl [3], quinolone [28], 5-nitrosalicylaldehyde [29], 3-alkoxy-2-naphthoic acid [30], coumarine [31] and benzothiazole [10][15] groups. In continuation of our studies on developing novel chemosensors containing fluorenyl moieties as fluorogenic group [32][33][34], we

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

• a good leaving group. The Criegee rearrangement was discovered in 1944 in the reaction of decaline ethylperoxoate 127 that rearranged into isomeric ester ketal 128 (Scheme 39) [291]. The mechanism of the Criegee rearrangement was studied using 2-alkoxy-2-propyl per-4-nitrobenzoates [292]. It was

• -oxabicycloalkanes 147a–d in formic or acetic acid containing catalytic amounts of sulfuric acid affords ω-alkoxy-(ω-3)-hydroxyalkanoic acid lactones 148a–d and 149a–d (Table 10) [297]. The transformation of 1-hydroperoxy-2-oxabicycloalkanones 147a–d into ω-alkoxy-(ω-3)-hydroxyalkanoic acid lactones 148a–d and 149a

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

• Roman Yu. Peshkov,
• Elena V. Panteleeva,
• Wang Chunyan,
• Evgeny V. Tretyakov and
• Vitalij D. Shteingarts

Beilstein J. Org. Chem. 2016, 12, 1577–1584, doi:10.3762/bjoc.12.153

• -coupling; cyanoarenes; reactive intermediates; reductive alkylation; Introduction Alkylcyanobiphenyls are well known largely due to their mesogenic properties, which were discovered by Gray in the 1970th [1][2]. Alkylcyanobiphenyls and their analogs (e.g., dialkyl and alkoxy alkyl derivatives) are still

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals

• Sonia L. Repetto,
• James F. Costello,
• Craig P. Butts,
• Joseph K. W. Lam and
• Norman M. Ratcliffe

Beilstein J. Org. Chem. 2016, 12, 1467–1475, doi:10.3762/bjoc.12.143

• impact of substituents upon the formation [10][11][19][20][21][22] and reactivity of charged intermediates [14] have all attracted scrutiny. A generic 2-alkoxy-2-alkyl-1,3-dioxolane A is used to illustrate the generally accepted specific acid-catalysed three-stage hydrolysis mechanism of orthoesters

• , initially undergo exclusive cleavage of the exocyclic alkoxy group [19]. In reviewing the case of orthoesters, Kresge et al. suggests two mechanistic extremes [19][24]. A concerted catalysed process, wherein the –OR group undergoes protonation as the C···O(H+)R bond begins to undergo cleavage. The

On the mechanism of imine elimination from Fischer tungsten carbene complexes

• Philipp Veit,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2016, 12, 1322–1333, doi:10.3762/bjoc.12.125

• complexes [16][17]. First representatives of multimetal carbene complexes M(CO)5(1R) bear α-ferrocenyl alkoxy carbenes :C(OR)Fc (1R, M = Cr, Mo, W; R = Me, Et; Fc = ferrocenyl) [18][19][20][21][22]. Nucleophilic substitution of the alkoxy substituent OR by amines gives access to α-ferrocenylamino Fischer

• -donating character of the amino substituent vs the alkoxy substituent thus increasing the C(carbene)–X double bond character (X = N, O) [62][63][64] and the loss of some attractive NH…Fe interaction (H…Fe(Fc-C) = 2.98 Å) in W(CO)5(E-2) [27][54][55][56][57][58][59]. The Gibbs free energy of activation for

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

• successfully used trialkyl orthoformates 13 to produce dialkyl (2-oxo-4-(trifluoromethyl)-1,2-dihydropyrimidin-5-yl)phosphonates 14 which were converted to dialkyl (4-alkoxy-2-oxo-4-(trifluoromethyl)-1,2,3,4-tetrahydropyrimidin-5-yl)phosphonates 15 through the nucleophilic addition of the liberated alcohol to

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• carboxylic acids [33][34][35][36][37][38][39][40]. These components form α-alkoxy-substituted β-ketoenamides as precursors of highly substituted pyridine derivatives. We therefore tried to independently prepare β-ketoenamides with this substitution pattern starting from simple 1,3-diketones such as 1a. An

• related reaction conditions [41][42][43][44][45]. In this context we want to notice that our approach to alkoxy-substituted β-ketoenamides via alkoxyallenes also allowed the synthesis of 5-acetyloxazoles with high flexibility, if the acid-labile trimethylsilylethyl group was introduced via the

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• atmospheric chemists to undertake physicochemical analysis of important climate related IPNs. In the atmosphere isoprene (1) has a half-life of ~1−2 hours [16]. It reacts readily with HO• and O2 generating alkoxy radical (RO•) intermediates (not shown) as well as hydroperoxy radicals (ROO•) such as rac-2 and

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• ; only anilides possessing a strongly donating alkoxy group meta to the directing group (para to the position where the C–H activation would occur) were reactive. However, we have since found that use of acetonitrile-free, in situ generated cationic palladium with arylureas as the directing group

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• synthesis of (−)-maoecrystal V [63]. During this study, the authors observed an unexpected result when ortho–halosubstituted diazo compounds were used. Here the formation of a β-lactone by the carbenoid insertion into the C(sp3)–H bond of the alkyl substituent of the alkoxy moiety of the ester (Scheme 21

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• -position functionalization is using electroorganic chemistry [69]. As shown in Figure 18, bisformyl protected piperazine 106 could be converted to 107 in 91% yield under anodic oxidation conditions at 500 g scale [70]. While this method is limited and only allows for functionalization with alkoxy groups

Biosynthesis of α-pyrones

• Till F. Schäberle

Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56

• interesting target of research, due to the fact that the progression of Alzheimer’s disease was slowed down by using anti-inflammatory drugs. Thus, selective COX-2 inhibitors, anti-inflammatory compounds themselves, might have beneficial effects in vivo. Several derivatives of 6-alkyl (alkoxy or alkylthio)-4

• monocyclic α-pyrones showing pheromone (47) and antitumor activity (48), respectively. Structures of 6-alkyl (alkoxy or alkylthio)-4-aryl-3-(4-methanesulfonylphenyl)pyrones. Structures of kavalactones. Strutures of germicins. Structures of the pseudopyronines. The structures of the monobenzo-α-pyrone

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• flavanoid bearing the triarylmethane motif [31][32]. Triarylmethanes are typically synthesized by a Friedel–Crafts-type substitution of the three alkoxy groups in a trialkyl orthoformate (Scheme 1A, method 1) [33][34][35] or by sequential two-step addition of electron-rich aromatic nucleophiles to activated

• designed a synthesis of the precursor 22 (Scheme 5) for the anti-breast-cancer agent 4 (Figure 1). Any method for the synthesis of 4 needs to take into account that it has two phenyl rings with different alkoxy groups at the respective C(4) position. We reasoned that one of the aryl groups could be a part

(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

• ]. Initially nitromethane adds to the chalcone moiety, followed by a nitronate addition to the α,β-unsaturated ester. The substrate scope was widely expanded, including the aromatic moieties containing halogens, alkyl and alkoxy groups. Also, ketones bearing aryl, heteroaryl and alkyl groups, provided the

Tandem processes promoted by a hydrogen shift in 6-arylfulvenes bearing acetalic units at ortho position: a combined experimental and computational study

• Mateo Alajarin,
• Marta Marin-Luna,
• Pilar Sanchez-Andrada and
• Angel Vidal

Beilstein J. Org. Chem. 2016, 12, 260–270, doi:10.3762/bjoc.12.28

• Academy, Base Aerea de San Javier, C/ Coronel López Peña s/n, 30720, Santiago de la Ribera, Murcia, Spain 10.3762/bjoc.12.28 Abstract 6-Phenylfulvenes bearing (1,3-dioxolan or dioxan)-2-yl substituents at ortho position convert into mixtures of 4- and 9-(hydroxy)alkoxy-substituted benz[f]indenes as

• initiated by an H shift step has been tested. Such acetal-fulvenes, under thermal activation, transformed into mixtures of the corresponding 4- and 9-(hydroxy)alkoxy-substituted benz[f]indenes in a 1:2 ratio. Analogous fulvenes bearing non-cyclic dialkoxymethyl units when submitted to similar thermal

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• (S)-sarin is levorotatory. Chirality has been attributed following the reviewed rules of Cahn, Ingold and Prelog [63][64] which classified the oxygen atom of the P=O bond as the minor priority compared to the alkoxy substituents [65]. In their 1988 work, Benschop and De Jong stated that the nerve

• cyclosarin in presence of β-CD were then studied at 25 °C and pH 9 and also compared with the hydrolysis of soman. Their enantiomers are not degraded at the same rate, the P(R)-isomers of sarin and cyclosarin reacting faster than P(S)-isomers at pH 9 (Table 11). The different alkoxy substituents on the

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

Beyond catalyst deactivation: cross-metathesis involving olefins containing N-heteroaromatics

• Kevin Lafaye,
• Cyril Bosset,
• Lionel Nicolas,
• Amandine Guérinot and
• Janine Cossy

Beilstein J. Org. Chem. 2015, 11, 2223–2241, doi:10.3762/bjoc.11.241

• reported in the literature. Macrocycle 64 was obtained from diene 63 in good yield in the presence of the GI catalyst under diluted conditions [63]. Once again, the presence of the two alkoxy substituents at the C2 position of the pyridyl rings might not be innocent in the success of the RCM and steric

Computational study of productive and non-productive cycles in fluoroalkene metathesis

• Markéta Rybáčková,
• Jan Hošek,
• Ondřej Šimůnek,
• Viola Kolaříková and
• Jaroslav Kvíčala

Beilstein J. Org. Chem. 2015, 11, 2150–2157, doi:10.3762/bjoc.11.232

• partial bonding of alkene and the alkoxy group of the alkoxybenzylidene ligand to ruthenium was detected with the exception of a syn–cis arranged alkene, for which just a weak inflexion was observed in analogy to [42]. No large differences in the energies of transition states 3d preceeding the formation

Supramolecular chemistry: from aromatic foldamers to solution-phase supramolecular organic frameworks

• Zhan-Ting Li

Beilstein J. Org. Chem. 2015, 11, 2057–2071, doi:10.3762/bjoc.11.222

• and aliphatic ammonium and, at high concentrations in chloroform, a chiral aliphatic ammonium induced 23 to produce helicity bias. One important difference between fluorine and alkoxy groups is that fluorine does not cause a steric effect on aromatic stacking. Zeng and co-workers demonstrated this

• about 1 nm in diameter. These folded structures could host alkylated saccharides in chloroform, which was stabilized by intermolecular hydrogen bonding formed between the carbonyl oxygen atoms of the foldamers and the hydroxy groups of the saccharides. By changing the position of the alkoxy groups, the

Copper-catalyzed aerobic radical C–C bond cleavage of N–H ketimines

• Ya Lin Tnay,
• Gim Yean Ang and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2015, 11, 1933–1943, doi:10.3762/bjoc.11.209

• , that undergoes β-carbon fragmentation to give p-tolunitrile (5a) and biaryl-2-isopropyl radical B (Scheme 5a). The aerobic oxygenation of C-radical B affords peroxy radical C, that is presumably reduced by Cu(I) species through the Fenton-type mechanism [57] to give alkoxy radical D [58]. Subsequent

• spirocyclization of the alkoxy radical D onto the benzene ring affords cyclohexadienyl radical F, oxygenation of which followed by C=O bond formation finally provides the oxaspirocyclohexadienone product 3a. Whereas, the oxidation of the benzylic radical B by the existing Cu(II) species to carbocation G and

• subsequent E1-type elimination of a proton provides biaryl alkene 4a (Scheme 5b). The presence of alkoxy radical D in the reaction process could be further supported by the reaction of biaryl hydroperoxide 6, which could be converted into the alkoxy radical D under copper-catalyzed aerobic reaction

Cross metathesis of unsaturated epoxides for the synthesis of polyfunctional building blocks

• Meriem K. Abderrezak,
• Kristýna Šichová,
• Nancy Dominguez-Boblett,
• Antoine Dupé,
• Zahia Kabouche,
• Christian Bruneau and
• Cédric Fischmeister

Beilstein J. Org. Chem. 2015, 11, 1876–1880, doi:10.3762/bjoc.11.201

• cross metathesis of 1 with methyl acrylate was transformed by means of nucleophilic ring-opening of the epoxide to furnish a diol, an alkoxy alcohol and an amino alcohol in high yields. Keywords: cross metathesis; epoxide; ruthenium catalysts; tandem reactions; Introduction Catalytic carbon–carbon

• that was further efficiently transformed into a 1,2-diol, a 1,2-alkoxy alcohol and a 1,2-amino alcohol. This strategy opens the way for numerous potential transformations involving the epoxide but also the functional group of the electron-deficient olefin. In particular, lactones should be accessible

An efficient synthesis of N-substituted 3-nitrothiophen-2-amines

• Sundaravel Vivek Kumar,
• Shanmugam Muthusubramanian,
• J. Carlos Menéndez and
• Subbu Perumal

Beilstein J. Org. Chem. 2015, 11, 1707–1712, doi:10.3762/bjoc.11.185

• , including alkyl (compounds 3f–h, 3j, 3o and 3q) and alkoxy (compounds 3i, 3k and 3p) substituents, even at the more hindered ortho-positions (3j, 3k, 3q). The preparation of a compound bearing a 1-naphthylamino substituent (compound 3r) also proceeded uneventfully. We also investigated the reactions of α

A facile synthetic route to benzimidazolium salts bearing bulky aromatic N-substituents

• Gabriele Grieco,
• Olivier Blacque and
• Heinz Berke

Beilstein J. Org. Chem. 2015, 11, 1656–1666, doi:10.3762/bjoc.11.182

• -step synthesis avoiding chromatographic work-up. In the key step triethyl orthoformate is reacted with the corresponding N1,N2-diarylbenzene-1,2-diamines and then further transformed in situ, by alkoxy abstraction using trimethylsilyl chloride (TMSCl), and concomitant imidazole ring closure. Keywords