Cross-metathesis reaction of α- and β-vinyl C-glycosides with alkenes

• Ivan Šnajdr,
• Kamil Parkan,
• Filip Hessler and
• Martin Kotora

Beilstein J. Org. Chem. 2015, 11, 1392–1397, doi:10.3762/bjoc.11.150

• -deoxyribosides [15]. Finally, there is also a method utilizing an excess of vinylmagnesium bromide in the reaction with 3,5-bis-O-TBDPS-protected 2-deoxy-D-ribofuranose giving rise to a mixture of diastereoisomeric diols. The diasteroisomers were separated and cyclized in the presence of MsCl to the

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

• , dibromide 83 was converted to bis-aldehyde 84. Finally, McMurry coupling of dialdehyde 84 provided the cyclophane derivative 85 (28%). Yamoto and co-workers have reported the synthesis of medium-sized cyclophanes, [2.n]metacyclophane-1,2-diols 86 and 87 by using the McMurry coupling as a key step (Figure 8

• was explained on the basis of a tandem isomerization of a terminal double bond followed by the macrocyclization with G-II (13). Finally, the oxidation of diols 186 and 189 generated cyclophanes 187 and 190, respectively (Scheme 30). Guan and coworkers [154] have reported a novel synthetic approach to

Novel stereocontrolled syntheses of tashiromine and epitashiromine

• Loránd Kiss,
• Enikő Forró and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2015, 11, 596–603, doi:10.3762/bjoc.11.66

• convenient route for the preparation of N-heterocyclic β-amino acid derivatives [40][41] or for the stereocontrolled synthesis of functionalized cispentacins [42] and their acyclic counterparts [43][44] (Figure 5). The oxidative ring cleavage of various vicinal diols and the transformation of the resulting

• dialdehyde intermediates has been efficiently applied in recent years for the synthesis of a series of valuable organic molecules [45][46][47][48][49][50][51][52]. In particular, Davies and co-workers have utilized the oxidative ring opening of cyclic vicinal diols followed by ring closure for access to

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

• method to synthesize protected syn-1,3-diols by performing intramolecular conjugate additions to a series of α,β-unsaturated esters and amides [71] (Scheme 8). Upon treatment of 24 with KHMDS and benzyaldehyde, a hemiacetal forms which provides the alkoxide nucleophile for the DCA reaction. These

Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

• Erdal Ertas,
• İlknur Demirtas and
• Turan Ozturk

Beilstein J. Org. Chem. 2015, 11, 403–415, doi:10.3762/bjoc.11.46

• reflectance of the complex decreased while transmittance increased with increased annealing temperature. Our easy synthesis of dithiin-containing compounds led to the production of various BEDT-TTF analogues, comprising monophenyldithiin, diphenyldithiin, diphenylthiophene and diols [40][46][53]. While

Anionic sigmatropic-electrocyclic-Chugaev cascades: accessing 12-aryl-5-(methylthiocarbonylthio)tetracenes and a related anthra[2,3-b]thiophene

• Laurence Burroughs,
• John Ritchie,
• Mkhethwa Ngwenya,
• Dilfaraz Khan,
• William Lewis and
• Simon Woodward

Beilstein J. Org. Chem. 2015, 11, 273–279, doi:10.3762/bjoc.11.31

• Laurence Burroughs John Ritchie Mkhethwa Ngwenya Dilfaraz Khan William Lewis Simon Woodward School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom 10.3762/bjoc.11.31 Abstract 1,4-Diols resulting from the double addition of ArCCLi (Ar = Ph

• Discussion Investigation of the chemistry of Scheme 2 commenced with the preparation of the required diols 8 through simple acetylide addition to o-phthalaldehyde (60–91% yield, see Supporting Information File 1). All of the additions proceeded in high yield, but under all conditions tried, no strong bias to

• equivalent trend in diols 8b–f where two distinct sets of equivalent signals are seen δH 6.14–6.20 and δH 6.23–6.35. On this basis we assign the higher chemical shift signal to the meso diastereomer. Cascade optimisation (Table 1) was carried out using 8a in THF unless otherwise stated. Typically diol 8a (ca

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

• Pablo Wessig,
• Roswitha Merkel and
• Peter Müller

Beilstein J. Org. Chem. 2015, 11, 74–84, doi:10.3762/bjoc.11.11

• convergent approach) and 29 [9] (Scheme 6). Based on ketones 27a–c and diols 28, 29 we obtained ARs 32a–c in two steps consisting of the established double activation acetalization [8] and the CuAAC, catalyzed by Cu/C, with moderate yields (Scheme 7). As mentioned above this sequential approach failed in the

NAA-modified DNA oligonucleotides with zwitterionic backbones: stereoselective synthesis of A–T phosphoramidite building blocks

• Boris Schmidtgall,
• Claudia Höbartner and
• Christian Ducho

Beilstein J. Org. Chem. 2015, 11, 50–60, doi:10.3762/bjoc.11.8

• with ammonium fluoride in methanol at elevated temperature, which afforded diols (S)-27 and (R)-27, each in 66% yield. DMTr protection under standard conditions then provided intermediates (S)-28 and (R)-28 in yields of 72% and 81%, respectively. Finally, phosphitylation of the 3'-hydroxy group gave

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

• Daniel I. Hădărugă,
• Nicoleta G. Hădărugă,
• Corina I. Costescu,
• Ioan David and
• Alexandra T. Gruia

Beilstein J. Org. Chem. 2014, 10, 2809–2820, doi:10.3762/bjoc.10.298

• isoaromadendrene oxide (22) (up to 0.2%), or the corresponding diols (up to 0.1%). Obtaining of O. basilicum L. essential oil/β-CD complex The O. basilicum L. essential oil/β-CD complex was obtained by using the controlled crystallization method from an ethanol/water suspension (due to the lower water solubility

Design and synthesis of novel bis-annulated caged polycycles via ring-closing metathesis: pushpakenediol

• Sambasivarao Kotha and
• Mirtunjay Kumar Dipak

Beilstein J. Org. Chem. 2014, 10, 2664–2670, doi:10.3762/bjoc.10.280

• synthesis of heptacyclic diol 22. The synthesis of diallylated hexacyclic diols. The attempted synthesis of heptacyclic diol via ring-rearrangement metathesis. Supporting Information Supporting Information File 428: Copies of 1H, 13C NMR and HRMS spectra for all new compounds. Acknowledgements We would

Regio- and stereoselective synthesis of new diaminocyclopentanols

• Evgeni A. Larin,
• Valeri S. Kochubei and
• Yuri M. Atroshchenko

Beilstein J. Org. Chem. 2014, 10, 2513–2520, doi:10.3762/bjoc.10.262

• of stereoselective epoxide opening of these cyclic amine derivatives are limited to the preparation of the corresponding diols under acidic conditions [23]. Other reported strategies involve the formation of diaminocyclohexanols from epoxides under basic conditions [24] or by activating the epoxides

De novo macrolide–glycolipid macrolactone hybrids: Synthesis, structure and antibiotic activity of carbohydrate-fused macrocycles

• Richard T. Desmond,
• Anniefer N. Magpusao,
• Chris Lorenc,
• Jeremy B. Alverson,
• Nigel Priestley and
• Mark W. Peczuh

Beilstein J. Org. Chem. 2014, 10, 2215–2221, doi:10.3762/bjoc.10.229

• remainder of the synthesis separately. Transacetalization of the C4,C6-O-benzylidene protecting group in methanol provided diols 9a and 9b, respectively in nearly quantitative yields. Chemoselective, DCC-mediated acylation of the primary alcohol group of 9a and 9b at 0 °C with pentenoic acid gave 10a (58

Visible light photoredox-catalyzed deoxygenation of alcohols

• Daniel Rackl,
• Viktor Kais,
• Peter Kreitmeier and
• Oliver Reiser

Beilstein J. Org. Chem. 2014, 10, 2157–2165, doi:10.3762/bjoc.10.223

• benzylic alcohols, α-hydroxycarbonyl, and α-cyanohydrin compounds. Moreover, the selective catalytic monoacylation of diols is possible, thus allowing efficient monodeoxygenations as exemplified in the conversion of (+)-diethyl tartrate to unnatural (+)-diethyl malate. Results and Discussion Following the

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

Palladium-catalysed cyclisation of alkenols: Synthesis of oxaheterocycles as core intermediates of natural compounds

• Miroslav Palík,
• Jozef Kožíšek,
• Peter Koóš and
• Tibor Gracza

Beilstein J. Org. Chem. 2014, 10, 2077–2086, doi:10.3762/bjoc.10.216

• tertiary allylic alcohol was performed in a two-step sequence. The addition of methyllithium to ester Z-17 and following deprotection of the corresponding alcohol 27 with aqueous acetic acid afforded tetraol 28 in good yield. Substrates syn-diols 33–35 (not bearing an α-O-protected group) were prepared in

• reaction with the corresponding Grignard reagent in the presence of CeCl3·2LiCl providing diols 33–35 in good overall yields and high diastereoselectivity (d.r. >20:1). Additionally, allylic acetate 37 was obtained starting from 33 in a seven-step sequence in 30% overall yield. The acetonisation of hydroxy

Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

• Maroš Bella,
• Bohumil Steiner,
• Vratislav Langer and
• Miroslav Koóš

Beilstein J. Org. Chem. 2014, 10, 1942–1950, doi:10.3762/bjoc.10.202

• formation (via an intermediate F) of 1-methyl-2-substituted-naphthalenes I, analogues of o-tolyl derivatives 4 and 5 (Scheme 2, final step of path 1), which were in present study, by contrast, isolated as stable products. Moreover, path 2 in Scheme 2 can be excluded, since no diols of type C (analogues of

• diols H in Scheme 3) were detected in the reaction mixture. To extend and confirm these observations, the analogous addition of 1 as well as 2 to another two representative carbohydrate aldehydes – 3-O-benzyl-1,2-O-isopropylidene-α-D-xylo-pentodialdo-1,4-furanose and 1,2:3,4-di-O-isopropylidene-α-D

Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

• Mahesh K. Lakshman,
• Manish K. Singh,
• Mukesh Kumar,
• Raghu Ram Chamala,
• Vijayender R. Yedulla,
• Domenick Wagner,
• Evan Leung,
• Lijia Yang,
• Asha Matin and
• Sadia Ahmad

Beilstein J. Org. Chem. 2014, 10, 1919–1932, doi:10.3762/bjoc.10.200

• hydroxy group, in good yields. In these reactions minor amounts of products arising by reaction at both hydroxy groups were observed. Similarly, reactions of 3-butenol gave products 4a and 4b in good to high yields, which were converted to the acyclic ribonucleoside-like diols (±)-5a and (±)-5b

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• and protection of 12a to 1,2-oxazine derivative 13. Conditions: a) 1. SnCl4, CH3CN, 4 h, −30 °C → rt; 2. TBSCl, imidazole, THF, 4 h, rt; b) NaBH4, EtOH, 4 h, −40 °C, 72%, dr 81:19; c) L-selectride, THF, 2 h, −10 °C, 73%, only 12a; d) TBSOTf, 2,6-lutidine, THF, 2 h, 0 °C. Synthesis of bicyclic diols 15

Aryl substitution of pentacenes

• Andreas R. Waterloo,
• Anna-Chiara Sale,
• Dan Lehnherr,
• Frank Hampel and
• Rik R. Tykwinski

Beilstein J. Org. Chem. 2014, 10, 1692–1705, doi:10.3762/bjoc.10.178

• purification step of the intermediate diols. Once formed, pentacenes 3a–h were obtained in moderate yield over two steps, as deep-blue solids. To expand the π-system in a linear fashion along the short molecular axis of the pentacene core, the general procedure described above was changed slightly, and ketone

Stereoselective synthesis of carbocyclic analogues of the nucleoside Q precursor (PreQ₀)

• Sabin Llona-Minguez and
• Simon P. Mackay

Beilstein J. Org. Chem. 2014, 10, 1333–1338, doi:10.3762/bjoc.10.135

• -diol core. Our previous experience in coupling diols and triols at high temperatures with chloro-intermediate 9 showed that more than one unprotected alcohol functionality leads to complex reaction mixtures and very low yields of isolated products [29], hence we protected all hydroxy groups as esters

Synthesis of a sucrose dimer with enone tether; a study on its functionalization

• Zbigniew Pakulski,
• Norbert Gajda,
• Magdalena Jawiczuk,
• Jadwiga Frelek,
• Piotr Cmoch and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2014, 10, 1246–1254, doi:10.3762/bjoc.10.124

• dimolybdenum methodology offers the hard proof of the absolute configuration of the vic-diols [27][28][29]. In this methodology, dimolybdenum tetraacetate acts as auxiliary chromophore allowing the application of electronic circular dichroism (ECD) to (otherwise in ECD non-observable) vic-diols. Mo2(OAc)4 when

• mixed with a chiral diol ligand forms complexes active in ECD in which a transfer of ligand chirality to the in situ-formed complex occurs in solution. Thus, stereochemistry of vic-diols can be easily assigned based on the helicity rule developed for this class of compounds. This rule correlates the

• evidenced by the steadily increasing number of reports in the literature about its successful application in the determination of the AC of 1,2-diols [30][31][32]. Therefore, in assignment of the AC of compounds under the present study (13, 14 and 16), we decided just to take advantage of the in situ

Homogeneous and heterogeneous photoredox-catalyzed hydroxymethylation of ketones and keto esters: catalyst screening, chemoselectivity and dilution effects

• Axel G. Griesbeck and
• Melissa Reckenthäler

Beilstein J. Org. Chem. 2014, 10, 1143–1150, doi:10.3762/bjoc.10.114

• contrast to that, photochemical redox activation is possible in the presence of titanium(IV) catalysts [19][20][21][22]. As shown in a series of papers by Sato and coworkers, carbonyl compounds 1 as well as imines couple with methanol to give the 1,2-diols or 1,2-amino alcohols, respectively, when

The Flögel-three-component reaction with dicarboxylic acids – an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives

• Mrinal K. Bera,
• Moisés Domínguez,
• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 394–404, doi:10.3762/bjoc.10.37

• , due to the symmetry of both vicinal diols a distinction between cis- and trans-35 (σv- or C2-symmetry respectively) by NMR is still not possible. The resulting diol 35 was therefore treated with an excess of (S)-Mosher's acid chloride to obtain the bis-(R)-Mosher ester 36 [74]. TLC analysis and NMR

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• , in an additional step, was reported to effect cyclodehydration of diols to furans and pyrans [47][48] (for recent examples for cyclodehydration protocols see [49][50]). Thereby, the volatile products were separated from O=P(OEt)3 through distillation. After our initial short communication [51] about

• was crystallized, the ketones 7a, 7b and 7d must have been enantiopure. Residual 3-chloropropanol (<15 mol % referred to 7), which was difficult to separate chromatographically, was removed after the next step either during the work up (diols 9) or chromatographically (on the sequence leading to 15a

• phase of the products 9 resulting in the crude diols 9a–d in a circa 90% purity according 1H NMR. Hence, the crude amino alcohols 9 were not further purified before the following cyclodehydration. Synthesis of cis-piperidinols B Cyclodehydration of amino alcohol syn-9a to piperidinol cis-11a under Appel

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• , 2,3-bis[(pinacolato)boryl]-1,3-diene 17, synthesized by treatment of 1,1-[bis(pinacolato)boryl]alkenes with excess of 1-bromo-1-lithioethene [56][57], were engaged in a triple aldehyde addition. 1,5-anti-Diols 18 were produced via successive Pt-catalyzed 1,4-diboration, allylboration reactions and

• . It was engaged in a one pot Diels–Alder cycloaddition with N-phenylmaleimide in the presence of various aldehydes to afford diols 39 as major diastereisomers (>95%) and in good overall yields (four steps) (Scheme 27). Conclusion Despite the synthetic potential of the boron-substituted 1,3-dienes and

• 15. Diels–Alder/cross-coupling reactions of 16. Metal catalyzed tandem Diels–Alder/hydrolysis reactions. Synthesis of anti-1,5-diols 18 by triple aldehyde addition. Catalytic enantioselective three-component hetero-[4 + 2]-cycloaddition/allylboration sequence. Synthesis of natural products using the