Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• , and even emergence of new reaction pathways [19][20][21][22][23][24]. To simulate the aqueous environment of enzyme-catalyzed physiological transformations, researchers seek to design and synthesize supramolecular hosts in a water-soluble way. The ionic and polyol forms of them would provide good

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• is a weak acid, sorbitol was observed with 5% yield along with 1% of sorbitan and 10% of isosorbide. The authors showed that a complex of borate-polyol and sorbitol or sorbitan as polyols was formed leading to an increase of their stabilities and thus their yields. When boric acid is replaced by

Stereoselective total synthesis and structural revision of the diacetylenic diol natural products strongylodiols H and I

• Pamarthi Gangadhar,
• Sayini Ramakrishna,
• Ponneri Venkateswarlu and
• Pabbaraja Srihari

Beilstein J. Org. Chem. 2018, 14, 2313–2320, doi:10.3762/bjoc.14.206

• reaction steps. A common aldehyde intermediate has been used for the synthesis of both strongylodiols. Keywords: alkylation; Cadiot–Chodkiewicz coupling; Corey–Bakshi–Shibata reduction; Mosher’s analysis; Wittig reaction; Introduction Diacetylenic polyol compounds [1][2] originated from marine sources

• have accomplished the total synthesis of the diacetylenic polyol natural products petrosiols A, D, E (11,12,13) [22][23] and strongylodiols A–D (1–4) [24]. Herein we describe the total synthesis of strongylodiols H and I (9 and 10). Results and Discussion Retrosynthesis for strongylodiol H and

• propargyl alcohol involving 13 linear steps, respectively. Investigations towards exploring the current strategy for accessing other natural products and their analogues are currently underway. Proposed structures of a selection of diacetylenic polyol natural products. Absolute configuration analysis of

An improved preparation of phorbol from croton oil

• Alberto Pagani,
• Simone Gaeta,
• Andrei I. Savchenko,
• Craig M. Williams and
• Giovanni Appendino

Beilstein J. Org. Chem. 2017, 13, 1361–1367, doi:10.3762/bjoc.13.133

• phorbol, making it possible to selectively partition them. In this way, the preparation of the diterpene polyol fraction was telescoped to only five operational steps (treatment of croton oil with sodium methylate, extraction with petroleum ether, evaporation, partition between THF and brine, and

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• typically a mixture of dicyclohexylmethane-4,4'-diisocyanate (HMDI, Figure 2) and it’s polyether prepolymer (CAS 531-70-03-9). While part B is a polyether or polyester polyol mixture which is proprietary [46]. Other aliphatic diisocyanate also used are 1,6-hexamethylene diisocyanate (HDI) and isophorone

• adventitious moisture with the diisocyanate. The degree of hardness of the dosimeter can be contolled by the type of polyol and catalyst utilized. Hardness ranging from rigid to tissue-like can be achieved [46]. The urethane reaction also tolerates up to relatively high addition (50%) of various solvents such

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

• , Kisarazu, Chiba 292-0818, Japan 10.3762/bjoc.13.47 Abstract Butyrolactol A is an antifungal polyketide of Streptomyces bearing an uncommon tert-butyl starter unit and a polyol system in which eight hydroxy/acyloxy carbons are contiguously connected. Except for its congener butyrolactol B, there exist no

• valine and its C-methylation with methionine and the polyol carbons are derived from a glycolysis intermediate, possibly hydroxymalonyl-ACP. Keywords: biosynthesis; butyrolactol; contiguous polyol; hydroxymalonyl-ACP; polyketide; Streptomyces; tert-butyl; Introduction Actinomycetes produce structurally

• -like structures [4][5][6][7][8]. Butyrolactol A (1) is an antifungal polyketide first isolated from Streptomyces rochei S785-16 [9] (Figure 1). The left half of 1 is the hydrophobic unconjugated tetraene system including one Z-olefin with a terminal tert-butyl group, whereas the hydrophilic polyol

Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

• Serena Traboni,
• Emiliano Bedini and
• Alfonso Iadonisi

Beilstein J. Org. Chem. 2016, 12, 2748–2756, doi:10.3762/bjoc.12.271

• conducted in short times with the requisite silyl chloride and a very limited excess of pyridine (2–3 equivalents). Under these conditions, that can be regarded as solvent-free conditions in view of the insolubility of the polyol substrates, the reactions are faster than in most examples reported in the

• to a broad range of conditions and feasible removal under conditions compatible with many other used alcohol protecting groups [1][2][3]. For this reason, silyl protecting groups are often serving as temporary protecting groups with polyol and saccharide substrates. The most robust and adopted silyl

• pyridine used, that is by far not sufficient for dissolution of the polar polyol substrates. Interestingly, reactions with pyridine were found to give slightly improved yields (within comparable times) on using a catalytic amount of TBAB (compare in Table 1 entries 6–8 with entry 9), which may be accounted

A robust synthesis of 7,8-didemethyl-8-hydroxy-5-deazariboflavin

• Matthias Bender,
• Henrik Mouritsen and
• Jens Christoffers

Beilstein J. Org. Chem. 2016, 12, 912–917, doi:10.3762/bjoc.12.89

• transformed to the corresponding protected ribitylamine via the oxime, which was submitted to reduction with LiAlH4. Key advantage compared to previous syntheses is the utilization of a polyol-protective group which allowed the chromatographic purification of a key-intermediate product providing the target

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• 1992, and looking back at the polyol receptors (such as 3) shows how far this field progressed. The use of boronic acids of Shinkai/James (7) [43][44][45] and the large cavities reported by Davis (8) [46] for binding saccharides has advanced the field far beyond our primitive designs (Figure 6). The

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• Apterostigma dentigerum, was investigated [115]. Again, a chemical analysis of an organic culture extract led to the isolation of a new polyketide bionectriol A (34), a glycosylated, polyunsaturated polyol, with so far undetermined ecological function. More recently, Wang et al. showed that the solitary leaf

Assembly of synthetic Aβ miniamyloids on polyol templates

• Sebastian Nils Fischer and
• Armin Geyer

Beilstein J. Org. Chem. 2015, 11, 2646–2653, doi:10.3762/bjoc.11.284

• the first step of Aβ oligomerization. In the present article, we further develop the idea of systematic variation of the oligomerization degree of Aβ fragments by using dynamic covalent chemistry for the assembly of miniamyloids. The size of a polyol template will limit the aggregation degree of Aβ

• avoided only when two different reactive groups are employed; that is why the reversible esterification between boronic acids and diols appeared an attractive solution to us. In a first approach, we planned to condense short peptide boronic acids with polyol templates for the assembly of an Aβ-dimer. The

• concept of tailoring the length of the peptide boronic acid and a polyol template is shown in Figure 2. Results and Discussion The shortest known functional expansion of the amyloidogenic Aβ-peptide is the β-amyloid (17–21) Leu-Val-Phe-Phe-Ala [20] which was investigated as both a C-terminal 1 and as an N

Robust bifunctional aluminium–salen catalysts for the preparation of cyclic carbonates from carbon dioxide and epoxides

• Yuri A. Rulev,
• Zalina Gugkaeva,
• Victor I. Maleev,
• Michael North and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2015, 11, 1614–1623, doi:10.3762/bjoc.11.176

• (Figure 3) was consistent with the MALDI–TOF data, showing that most of the polymer has a molecular weight between 300 and 1000 Daltons. This type of low molecular weight polycarbonate–polyol is currently attracting much interest associated with its use in sustainable polyurethanes [35]. To show 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

• reactions proceeded in good yields (71–84%) and high diastereoselectivities. This work has been useful because the syn-1,3-diol moiety is commonly observed in many natural products, most notably in polyol macrolide antibiotics [72][73][74]. Performing CA reactions on chiral lactams has been a common method

Anion effect controlling the selectivity in the zinc-catalysed copolymerisation of CO₂ and cyclohexene oxide

• Sait Elmas,
• Muhammad Afzal Subhani,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 42–49, doi:10.3762/bjoc.11.7

• many of the physicochemical properties of the polymer, such as the glass-transition temperature (Tg). With incorporated ether linkages, a molecular weight in the oligomer range and at least two terminal OH groups, polyethercarbonates are interesting polyol building blocks in polyurethane chemistry [8

A modular phosphate tether-mediated divergent strategy to complex polyols

• Paul R. Hanson,
• Susanthi Jayasinghe,
• Soma Maitra,
• Cornelius N. Ndi and
• Rambabu Chegondi

Beilstein J. Org. Chem. 2014, 10, 2332–2337, doi:10.3762/bjoc.10.242

• Paul R. Hanson Susanthi Jayasinghe Soma Maitra Cornelius N. Ndi Rambabu Chegondi Department of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045-7582, USA 10.3762/bjoc.10.242 Abstract An efficient and divergent synthesis of polyol subunits utilizing a phosphate tether

• five polyol fragments. Each of the product polyols bears a central 1,3-anti-diol subunit with differential olefinic geometries at the periphery. Keywords: phosphate-tether; one-pot; sequential processes; organophosphorus; polyol; stereodivergent; Introduction 1,3-anti-Diol subunits are a central

• protocols [27][28][29][30][31][32]. Herein, we report a modular, divergent approach to construct advanced polyol intermediates 10–14 and 17–21 in one- or two-pot sequences utilizing the innate properties of a phosphate tether. Taken collectively, this modular, divergent 3-component coupling strategy

The chemoenzymatic synthesis of clofarabine and related 2′-deoxyfluoroarabinosyl nucleosides: the electronic and stereochemical factors determining substrate recognition by E. coli nucleoside phosphorylases

• Ilja V. Fateev,
• Konstantin V. Antonov,
• Irina D. Konstantinova,
• Tatyana I. Muravyova,
• Frank Seela,
• Roman S. Esipov,
• Anatoly I. Miroshnikov and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2014, 10, 1657–1669, doi:10.3762/bjoc.10.173

• chromatography: reversed phase octadecyl–Si 100 polyol (0.03 mm), 25 × 190 mm (Merck, Germany). The progress of the synthesis of compounds 2 and 3a and their purity was monitored and checked by TLC [Sorbophil (Merck, Germany)]. Crystalline (99%) phosphoric acid was from Merck (Germany). Acetyl bromide (99%), tri

• reaction progress by HPLC. The remaining 2-chloroadenine was filtered off, the filtrate was concentrated in vacuo to ca. 35 mL, the solution was placed on the column [octadecyl–Si 100 polyol (0.03 mm); 25 × 190 mm], and the arabinoside 4 was eluted with EtOH (7%) in water to give, after evaporation and

• , the filtrate was concentrated in vacuo to ca. 40 mL, and the solution was placed on the column [octadecyl–Si 100 polyol (0.03 mm); 20 × 130 mm]. The non-reacted heterocyclic base was eluted with water, and arabinoside 4a was eluted with EtOH (1% v/v) in water to give, after evaporation and drying in

Stereoselective synthesis of the C79–C97 fragment of symbiodinolide

• Hiroyoshi Takamura,
• Takayuki Fujiwara,
• Isao Kadota and
• Daisuke Uemura

Beilstein J. Org. Chem. 2013, 9, 1931–1935, doi:10.3762/bjoc.9.228

• , Hiratsuka 259-1293, Japan 10.3762/bjoc.9.228 Abstract Symbiodinolide is a polyol marine natural product with a molecular weight of 2860. Herein, a streamlined synthesis of the C79–C97 fragment of symbiodinolide is described. In the synthetic route, a spiroacetalization, a Julia–Kocienski olefination, and a

• Sharpless asymmetric dihydroxylation were utilized as the key transformations. Keywords: Julia–Kocienski olefination; polyol marine natural product; Sharpless asymmetric dihydroxylation; spiroacetalization; symbiodinolide; Findings A 62-membered polyol marine natural product, symbiodinolide (1, Figure 1

Copper-catalyzed aerobic aliphatic C–H oxygenation with hydroperoxides

• Pei Chui Too,
• Ya Lin Tnay and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2013, 9, 1217–1225, doi:10.3762/bjoc.9.138

• direct 1,4-dioxygenation of alkane 10 was demonstrated by using the present method. Further studies will be carried out to develop more robust and efficient catalytic aerobic radical transformations for polyol synthesis from rather simple alkanes. Aliphatic C–H oxidation with amidines and ketimines by

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

• Alicja Schlange,
• Antonio Rodolfo dos Santos,
• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2011, 7, 1412–1420, doi:10.3762/bjoc.7.165

• time-consuming removal at the completion of the process [21], hindering the use of this method in a large-scale production. Therefore in recent years the colloidal method was often employed as the standard preparation technique for Pt deposition on carbon support. In this process (polyol reduction

• metallic Pt particles, as shown in Equation 2: The main advantage of this polyol synthesis is that the acetate can also serve as a stabilizer for Pt colloids through the formation of chelate-type complexes through its carboxyl group [24]. The application of stabilization agents to protect Pt particles from

• agglomeration is not necessary. A precondition for a homogenous formation of nuclei during the polyol synthesis is the choice of a proper heating method. Conventional heating strategies, such as oil baths or heat exchangers, usually exhibit a heterogeneous temperature distribution including the possibility of

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• 3000 g∙mol−1 could be obtained. The same procedure was used by Johnsen et al. with a different polyol, i.e., propanetriol instead of 1,6-hexanediol [114]. A biocompatible hydrophobic liquid core, Myglyol 812 triglyceride, was used in the droplets to yield core–shell polyurethane/urea for the

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length

• Florian K. Wolf,
• Anna M. Fischer and
• Holger Frey

Beilstein J. Org. Chem. 2010, 6, No. 67, doi:10.3762/bjoc.6.67

• ][24][25][26] has proven to be a versatile and highly potent multifunctional core molecule [27][28][29]. Derivatization and functionalization of the peripheral hydroxy groups of this polyether-polyol have afforded a number of carrier systems [30][31][32][33][34], matching the concept outlined above. In

• received. The synthesis of hb-PG was conducted as described in previous publications, using the slow monomer addition technique [21][25][26]. “Grafting from” polymerization of glycolide with hyperbranched polyglycerol-polyol as a macroinitiator. In a typical experiment, exemplified for the synthesis of