Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• -vicinal diol of 11 to give 12. From there, we obtained the corresponding methylamine derivative 13 by using the reductive amination conditions outlined herein. Compound 13 presents one less carbon between the five-membered ring and the amino group, in comparison to the other glycamines obtained. Both

Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids

• Simon Drescher,
• Vasil M. Garamus,
• Christopher J. Garvey,
• Annette Meister and
• Alfred Blume

Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99

• synthesised from the corresponding diol (HO-C18pPhC18-OH) by established phosphorylation and quarternisation reactions described previously [38]. The long-chain, phenylene-modified 1,ω-diol in turn was prepared using a bis-Sonogashira cross-coupling reaction [37] with PdCl2(PPh3)2 as catalyst and tetra-n

Synthesis of D-manno-heptulose via a cascade aldol/hemiketalization reaction

• Yan Chen,
• Xiaoman Wang,
• Junchang Wang and
• You Yang

Beilstein J. Org. Chem. 2017, 13, 795–799, doi:10.3762/bjoc.13.79

• ). The reaction of 5 with ethanethiol in the presence of hydrochloric acid followed by selective protection of the 4,5-diol with 2,2-dimethoxypropane using pyridinium p-toluenesulfonate as the promoter gave the 4,5-O-isopropylidene derivative 6 in 71% yield over two steps [40]. Treatment of diol 6 with

• spectra of 8 (see Supporting Information File 1 for details). Cleavage of the isopropylidene acetal group in 8 under acidic conditions gave diol 9 (50%). However, oxidative cleavage of diol 9 with sodium periodate resulted in the unexpected formation of α,β-unsaturated aldehyde 10 in 71% yield, indicating

• isopropylidene acetal group in 7 was cleaved under acidic conditions to produce triol 11 in 86% yield (Scheme 3). Cleavage of the resulting vicinal diol in 11 with sodium periodate led to the C4 aldehyde 3 in nearly 60–70% yield. In this oxidative cleavage reaction, almost no elimination product was found based

Cyclodextrins tethered with oligolactides – green synthesis and structural assessment

• Cristian Peptu,
• Mihaela Balan-Porcarasu,
• Alena Šišková,
• Ľudovít Škultéty and
• Jaroslav Mosnáček

Beilstein J. Org. Chem. 2017, 13, 779–792, doi:10.3762/bjoc.13.77

• -containing polymers while simplifying the complexity induced by multifunctional initiator through partial benzylation of the β-CD resulting in a CD-diol. Also, the ROP of D,L-LA catalyzed by 4-dimethylaminopyridine and initiated by all 21 OH groups of β-CD was employed by Xu et al. [15]. However, the above

Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

• Carmen Moreno-Marrodan,
• Francesca Liguori and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73

• and 79% selectivity to alkene and 95% to the Z isomer (Table 2, entry 19) [136]. 2-Butyne-1,4-diol From an industrial point of view, there is a great interest in the selective semi-hydrogenation reaction of 2-butyne-1,4-diol (13) under flow conditions, since cis-2-butene-1,4-diol (13a) is an important

Fluorinated cyclohexanes: Synthesis of amine building blocks of the all-cis 2,3,5,6-tetrafluorocyclohexylamine motif

• Tetiana Bykova,
• Nawaf Al-Maharik,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2017, 13, 728–733, doi:10.3762/bjoc.13.72

• % yield), however, diepoxides 8b and 8c (35%) could not be separated, and therefore were taken as a mixture of isomers to the next step in the reaction sequence. Treatment of 8a with Et3N·3HF at 140 °C resulted in its full conversion to the hydrofluorinated ring-opened diol 9a as a single regioisomer, a

Exploring endoperoxides as a new entry for the synthesis of branched azasugars

• Svenja Domeyer,
• Mark Bjerregaard,
• Henrik Johansson and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2017, 13, 644–647, doi:10.3762/bjoc.13.63

• unless stored at −20 °C. However, protection of the diol moiety as an acetonide to give endoperoxides 22 and 23 rendered the compounds stable at ambient temperature. Compounds 18–23 lend themselves to undergo a wide range of chemical transformations and are therefore valuable building blocks that will

• allow in-depth exploration of the chemistry of this class of azasugar precursors. Some preliminary experiments were performed to assess the possibilities that these building blocks grant. Endperoxide 19 was epoxidized under standard conditions to provide the desired epoxide 25 and the anti-diol 26 as a

• by-product. Likely, diol 26 is formed by ring-opening of the epoxide by water present in the mCPBA and the reaction could be optimised by performing the reaction under anhydrous conditions. Attempts at cleaving the endoperoxide bond of 20 and 21 by catalytic hydrogenation resulted in rapid

Synthesis of new pyrrolidine-based organocatalysts and study of their use in the asymmetric Michael addition of aldehydes to nitroolefins

• Alejandro Castán,
• Ramón Badorrey,
• José A. Gálvez and
• María D. Díaz-de-Villegas

Beilstein J. Org. Chem. 2017, 13, 612–619, doi:10.3762/bjoc.13.59

• the dioxolane moiety with trifluoroacetic acid, d) reconstruction of the dioxolane moiety by reaction of the diol with the corresponding dimethoxyacetal in the presence of SnCl2 and e) N-deprotection of the pyrrolidine by exposure of the benzylcarbamate to molecular hydrogen in the presence of

• catalytic Pd/C. In this way organocatalysts OC3–OC10 were obtained (Scheme 3 and Scheme 4). In addition another new organocatalyst, OC11, with a different bulky substituent at C2 in the pyrrolidine moiety was prepared. Reacting diol 7 with 1,3-dichlorotetraisopropyldisiloxane in the presence of imidazole

Studies directed toward the exploitation of vicinal diols in the synthesis of (+)-nebivolol intermediates

• Runjun Devi and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2017, 13, 571–578, doi:10.3762/bjoc.13.56

• asymmetric synthesis of (R)-1-((R)-6-fluorochroman-2-yl)ethane-1,2-diol, (R)-1-((S)-6-fluorochroman-2-yl)ethane-1,2-diol and (S)-6-fluoro-2-((R)-oxiran-2-yl)chroman, which have been used as late-stage intermediates for the asymmetric synthesis of the antihypertensive drug (S,R,R,R)-nebivolol. Noteworthy is

• have demonstrated that the synthesis of 1a could be achieved using the 2-substituted chroman derivatives (R)-1-((R)-6-fluorochroman-2-yl)ethane-1,2-diol (2) and (R)-1-((S)-6-fluorochroman-2-yl)ethane-1,2-diol (3) or the corresponding chroman epoxides 4 and 5 as late-stage intermediates. Although the

• (±)-2 is not feasible. Thus, the presence of an activating substituent (e.g., a nitro group) at the C-5 position of the benzene ring might be helpful in synthesizing molecules similar to 2 [31][32]. The failure to achieve an intramolecular cyclization of the diol via an SNAr reaction caused us to

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

• receptor modulator, 3-[4-(1-piperidinoethoxy)phenyl]spiro[indene-1,1’-indane]-5,5’-diol hydrochloride (216) which may be used for a new treatment of hot flush [88]. In this synthesis, the reaction of 5-methoxyindan-1-one (212) with the Grignard reagent 217 followed by acid-catalyzed dehydration and

Biosynthetic origin of butyrolactol A, an antifungal polyketide produced by a marine-derived Streptomyces

• Enjuro Harunari,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2017, 13, 441–450, doi:10.3762/bjoc.13.47

• intriguing feature of this molecule is the highly oxygenated carbon chain in which eight hydroxy groups, one of which is used for lactone formation, are contiguously aligned. A 1,3-diol is a common structural element in aliphatic polyketides because the incorporation of malonate-precursors gives rise to the

• alternative alignment of the methylene and the oxygenated carbons. Meanwhile, a 1,2-diol in polyketides is known to be formed by hydroxylation of methylene carbons as seen in the biosynthesis of erythromycin or amphotericin B [17][18]. The contiguously hydroxylated carbon chain of 1 is quite unusual as a

• to C-4) and the pentaol (C-5 to C-9) moieties (Figure 3), suggesting that the contiguous polyol system is not formed by methylene hydroxylation. Another possible pathway for 1,2-diol formation is the incorporation of hydroxymalonyl-ACP from a glycolytic intermediate for chain elongation [23]. To

Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

• Sophie Letort,
• Michaël Bosco,
• Benedetta Cornelio,
• Frédérique Brégier,
• Sébastien Daulon,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2017, 13, 417–427, doi:10.3762/bjoc.13.45

• fenitrothion (Figure 4) were also investigated. Finally, compounds 1–4 were tested for their detoxification ability against the nerve agent soman. Results and Discussion Synthesis The regioselective disubstitution of diol 6 (Scheme 1) was the key step to access derivatives 2 and 3. The synthetic methodology

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

• Maximilian Maier,
• Magnus S. Schmidt,
• Markus Ringwald and
• Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

• ) was synthesized from cis-but-2-ene-1,4-diol (17) using two different pathways; both reactions resulted in poor yields and product quality. Unfortunately, the reaction of 18 with allylamine did not result in the formation of 19, but to the undesired cyclic compound 20. The formation of the latter

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• glycosylation of mannosazide acceptor 18 (Scheme 3) to form the corresponding α-linked trisaccharide, which, subsequent to removal of the 4,6-benzylidene group under acidic conditions, provided diol 22 that was in turn converted into reducing-end trisaccharide 3 by selective placement of a TBS ether [28] on the

• obtain 35, required several protecting group manipulation steps: cleavage of the two acetate esters of 31 to produce diol 32 was followed by the reaction with trimethyl orthoacetate to provide the ortho-ester 33, which was regioselectively opened under acidic conditions to afford disaccharide acceptor 34

Silyl-protective groups influencing the reactivity and selectivity in glycosylations

• Mikael Bols and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2017, 13, 93–105, doi:10.3762/bjoc.13.12

• available silyl-protective groups are trimethylsilyl (TMS), triethylsilyl (TES), tert-butyldimethylsilyl (TBS), tert-butyldiphenylsilyl (TBDPS), triisopropylsilyl (TIPS) as well as the diol-protective groups DTBS and TIPDS (Figure 1). Silyl groups have also early been used in the carbohydrate field to

O-Alkylated heavy atom carbohydrate probes for protein X-ray crystallography: Studies towards the synthesis of methyl 2-O-methyl-L-selenofucopyranoside

• Roman Sommer,
• Dirk Hauck,
• Annabelle Varrot,
• Anne Imberty,
• Markus Künzler and
• Alexander Titz

Beilstein J. Org. Chem. 2016, 12, 2828–2833, doi:10.3762/bjoc.12.282

• a ratio of α/β = 2:1. After separation of the anomers, pure methyl α-L-selenofucoside (1) was finally obtained after deprotection of the α-anomer in 25% over 5 steps from L-fucose (4). A selective methylation of the hydroxy group in position 2 requires prior protection of the cis-diol in position 3

• Fischer-type glycosylation and pure allyl α-fucoside (7) was obtained after crystallization in 43% yield (Scheme 2). Selective protection of the 3,4-cis-diol as an acetonide followed by methylation of the hydroxy group in position 2 yielded derivative 8 in 85% yield over two steps. Then, the acetonide

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

• -diphenylethen-1,2 diol (11) in 6% isolated yield (Scheme 2). At this stage of our investigation, PS-BEMP 5 was tested as the packing material of fixed-bed reactors with potential long-term stability. A micro-HPLC with minimized extra-column volumes was used as the pumping system. The fixed-bed microreactor R5

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

• Xiao Huang,
• Li Yang,
• Rikard Emanuelsson,
• Jonas Bergquist,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

• M resulted in lower yields, probably due to decrease of the reaction rate. The yield could also be improved by dividing the addition of the diol 2 into several portions, added over two days. Two or three portions were found to result in the highest yield, with more portions not changing the yield

• , diol 7 was modified by protecting the ethynyl function with a TMS group, yielding 7’, expecting an improved yield from a better solubility of this diol in toluene. However, the transetherification reaction gave almost no conversion after 2 days. By changing the solvent to dichloroethane a yield of 12

Synthesis of polyhydroxylated decalins via two consecutive one-pot reactions: 1,4-addition/aldol reaction followed by RCM/syn-dihydroxylation

• Michał Malik and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2016, 12, 2602–2608, doi:10.3762/bjoc.12.255

• a result, derivatives 17 and 18 were obtained, respectively. The synthesis of aldehyde (S)-10 was initiated from D-mannitol. A known procedure led to compound 19 [48], which was easily transformed into diol 20, a convenient precursor of aldehyde (S)-10 (Scheme 4). Since such an aldehyde would be

Radical polymerization by a supramolecular catalyst: cyclodextrin with a RAFT reagent

• Kohei Koyanagi,
• Yoshinori Takashima,
• Takashi Nakamura,
• Hiroyasu Yamaguchi and
• Akira Harada

Beilstein J. Org. Chem. 2016, 12, 2495–2502, doi:10.3762/bjoc.12.244

• distributed polymers. In the presence of 1,6-hexanediol (C6 diol) which works as a competitive molecule by being included in the α-CD cavity, the reaction yield was lower than that without C6 diol. Keywords: cyclodextrin; radical polymerization; RAFT polymerization; substrate recognition site; supramolecular

• gave polymers with higher molecular weights and wider distributions (Table 1, entries 1 and 4). In order to investigate the effect of encapsulation of monomer by α-CD moiety, the reactions in the presence of 1,6-hexanediol (C6 diol) as a competitive guest molecule were also investigated. C6 diol was

• selected as a non-ionic molecule with a high association constant to α-CD (Ka = 134 M−1 ) [70]. In the presence of C6 diol, the reaction yields dropped to 63–72%, whereas the molecular weights of the polymers increased (22.9 and 19.4 kDa in entries 3 and 6, respectively). It is considered that by

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• to orthogonally protected amino acids 46 and 47 (Scheme 7) [58]. Installation of the C-2 stereocentre again began with Garner’s aldehyde 48 and Wittig olefination, followed by Sharpless dihydroxylation to stereoselectively afford diol 49 [59][60]. The C-2 epimer was accessed via Still–Gennari

• olefination of aldehyde 48 to afford the Z-olefin, which underwent dihydroxylation using potassium osmate to afford diol 50 [61][62]. With both diastereomers in hand, conversion to protected amino acids 46 and 47 was effected in four steps. With amino acids 46 and 47 in hand, conversion to the corresponding

• cyclic guanidines 51 and 52 was initiated through cleavage of the N,O-acetonide and guanylation using isothiourea 33 activated with HgCl2 (Scheme 8). Cyclisation of the guanidine afforded protected β-hydroxyenduracididine 51 in 21% yield in seven steps from diol 49. The C-2 epimer 47 was converted to β

A new and expeditious synthesis of all enantiomerically pure stereoisomers of rosaprostol, an antiulcer drug

• Wiesława Perlikowska,
• Remigiusz Żurawiński and
• Marian Mikołajczyk

Beilstein J. Org. Chem. 2016, 12, 2234–2239, doi:10.3762/bjoc.12.215

• synthesis of the stereoisomers 1a and 1c an alternative, more efficient method for the conversion of the enantiomeric methyl esters 6 into 1a or 1c was also elaborated as a two-reaction sequence. The first step comprises a reduction of 6 by L-Selectride at −45 °C affording the corresponding diol 8. In the

DNA functionalization by dynamic chemistry

• Zeynep Kanlidere,
• Oleg Jochim,
• Marta Cal and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2016, 12, 2136–2144, doi:10.3762/bjoc.12.203

• generate libraries of molecules from simpler building blocks by reversible reactions under thermodynamic control. Here we focus on the chemical modification of DNA oligonucleotides with acyclic diol linkers and demonstrate their potential for the deoxyribonucleic acid functionalization and generation of

The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• ) THF (3 in Scheme 1, the general structure of which is today often as a simplification referred to as “THF diol”) [8]. In addition, they found that this reaction proceeds with high stereoselectivity (vide infra) and demonstrated that the reaction is not only limited to terpenes such as geranyl- (1b, R

• reaction; cf. Scheme 3). In this case the diol and the metal oxide form a glycol ester intermediate which then undergoes an intramolecular oxidative addition to a remote double bond. Thereby, type B oxidative cyclizations converge to the same (or very similar) reactive intermediate as is passed through in

• type A reactions (Scheme 3). A relevant advantage of this approach is that enantiomerically pure products can be obtained when enantiomerically pure diol starting materials are used. A subgroup of closely related starting materials may contain an alkyl ether instead of a free hydroxy group at C6 (R ≠ H