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

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

• functionalized carboxylic acids that take part in decarboxylative additions to maleimides is presented in Scheme 5. Reasonable yields of adducts were obtained for alkyl radicals with α-alkoxy substituents. Two diastereomers of 22 as a 1:1 mixture were obtained from 2-tetrahydrofuroic acid in a very pleasing

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki–Miyaura reactions: relative reactivity of K[4-RC₆F₄BF₃] and the role of silver-assistance in acceleration of transmetallation

• Vadim V. Bardin,
• Anton Yu. Shabalin and
• Nicolay Yu. Adonin

Beilstein J. Org. Chem. 2015, 11, 608–616, doi:10.3762/bjoc.11.68

• the data by Sheppard for CCl3F or benzene [45]. When R = H, Bu, or alkoxy group, inductive constants σI (4-RC6F4) consist of 0.16–0.18. The 4-RC6F4 groups with R = F, pyrazol-1-yl, pyrrol-1-yl, indol-1-yl, imidazol-1-yl and benzimidazol-1-yl possess a higher electron-withdrawing effect (σI = 0.21

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

• , and easy to handle. Though organosilicon reagents have been used in rhodium-catalyzed asymmetric 1,4-additions, many of them rely on the use of moisture-sensitive organotri(alkoxy)silanes or the addition of an acid or base in order to obtain the product in high yield and enantioselectivity [154

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

• different stoichiometries. It should be noted that alkoxy and silyl functionalities are tolerated in the reaction. Experimental The catalyst RuH2(CO)(PPh3)3 was prepared according to literature [19] and stored under Argon with exclusion of water. General procedure for C–H activation In a sealed Schlenk

Synthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization

• William H. Hersh

Beilstein J. Org. Chem. 2015, 11, 184–191, doi:10.3762/bjoc.11.19

• of 33 kcal/mol [31]. Since the replacement of an alkyl or aryl group in phosphines by an acyl group lowered the epimerization barrier by >13 kcal/mol, it seemed reasonable to propose the same could happen by a similar replacement of an alkoxy group in phosphite triesters. Although the required

• shortly. The straightforward route for the synthesis of 3 involves the Arbuzov reaction of a trialkyl phosphite ester with an acid chloride [40], necessarily giving the dialkyl acylphosphonate with identical alkoxy groups. Thus, no comparable synthesis of 1 could be carried out since the dinucleoside

• contrast, did not yield a trigonal planar transition state, but rather gave a T-shaped transition state. In fact, such a result has been reported for PF3 [59][60] and is due to the presence of the highly electronegative atoms bound to phosphorus. While the alkoxy groups of the phosphite triester are

Enhancing the reactivity of 1,2-diphospholes in cycloaddition reactions

• Almaz Zagidullin,
• Vasili Miluykov,
• Elena Oshchepkova,
• Artem Tufatullin,
• Olga Kataeva and
• Oleg Sinyashin

Beilstein J. Org. Chem. 2015, 11, 169–173, doi:10.3762/bjoc.11.17

• , phosphinidenes, etc. [2]. At the same time, the presence of electron-withdrawing substituents (cyano-, alkoxy-, or halo-) at the phosphorus atom reduces the aromaticity of the monophosphole ring and facilitates cycloaddition reactions resulting in novel 7-phosphanorbornenes [5][6], which was verified by

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

• Bianca Rossi,
• Nadia Pastori,
• Simona Prosperini and
• Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

• the corresponding alkoxy radical (Scheme 4, reaction 4). The latter undergoes hydrogen abstraction from the C–H bond of THF in the α-position of the oxygen (Scheme 4, reaction 5). This promotes the formation of a carbon-centered nucleophilic radical, which in turn quickly adds to the activated carbon

Mono- and multilayers of molecular spoked carbazole wheels on graphite

• Stefan-S. Jester,
• A. Vikas Aggarwal,
• Daniel Kalle and
• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 2783–2788, doi:10.3762/bjoc.10.295

• ]. These represent basic building blocks for a supramolecular Archimedean surface tessellation system [9]. Thereby, the highly oriented pyrolytic graphite (HOPG) acts as a template along the main axis directions of which the alkyl/alkoxy side chains align [10][11], and consequently the superstructures can

• solvent, octanoic acid (OA), which has also previously been used for imaging MSWs [2][4]. We compared the so-obtained images of MSW 2 with its precursor 1 under similar conditions. In all images, regions covered with conjugated backbones and alkoxy side chains are observed in bright and dark colors

• the HOPG main axes (and alkoxy side chain alignment directions) [10][11], d1. A high resolution STM image is shown in Figure 2c, and a molecular model is superimposed to a copy of the image in Figure 2d. On a first sight, a bright hexagonal frameline (corresponding to the six rim segments) is observed

Self-assembled monolayers of shape-persistent macrocycles on graphite: interior design and conformational polymorphism

• Joscha Vollmeyer,
• Friederike Eberhagen,
• Sigurd Höger and
• Stefan-S. Jester

Beilstein J. Org. Chem. 2014, 10, 2774–2782, doi:10.3762/bjoc.10.294

• –alkynylene macrocycles are promising candidates as future mounts for functional units. These are separated from each other and cannot interact intermolecularly if the rings are adsorbed in parallel to the substrate. The exterior of the macrocycles can be substituted with alkyl side chains (or their alkoxy

• 2D superstructures are not predictable [17] or show a conformational polymorphism [18], also as an effect of varying compound concentrations in the supernatant solution [19][20]. A recent approach investigating macrocycles of triangular, quadratic, pentagonal, and hexagonal shapes that carry alkoxy

• side chains pointing away in normal direction from their sides has led to the concept of molecular polygons [4]. An example for the schematic design of an alkoxy side chain substituted molecular hexagon and its characteristic side-chain interdigitation concept are shown in Figure 2a and b, respectively

Synthesis of nanodiamond derivatives carrying amino functions and quantification by a modified Kaiser test

• Gerald Jarre,
• Steffen Heyer,
• Elisabeth Memmel,
• Thomas Meinhardt and
• Anke Krueger

Beilstein J. Org. Chem. 2014, 10, 2729–2737, doi:10.3762/bjoc.10.288

• observed surface loading for 13 is higher due to secondary reactions of already grafted alkoxy silanes [5]. In a first series of experiments the assay was carried out on nanodiamond samples 5 and 15 using the protocol reported by Troll et al. [22]. Surprisingly, very low values for the amino group loading