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Search for "Sharpless asymmetric epoxidation" in Full Text gives 13 result(s) in Beilstein Journal of Organic Chemistry.

Synthesis of ether lipids: natural compounds and analogues

  • Marco Antônio G. B. Gomes,
  • Alicia Bauduin,
  • Chloé Le Roux,
  • Romain Fouinneteau,
  • Wilfried Berthe,
  • Mathieu Berchel,
  • Hélène Couthon and
  • Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

Graphical Abstract
  • from allyl alcohol (Figure 7) [82]. The Sharpless asymmetric epoxidation of allyl alcohol followed by tosylation produced glycidyl tosylate 7.1a (Figure 7). The reaction of palmityl alcohol (C16H33-OH) in the presence of a catalytic amount of BF3 open regio- and stereoselectively the epoxide to produce
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Published 08 Sep 2023

Syntheses of spliceostatins and thailanstatins: a review

  • William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

Graphical Abstract
  • exocyclic epoxide prior to the formation of the C-6–C-9 conjugated diene was necessary in order to avoid the unwanted epoxidation of the C-6–C-7 olefin. Koide employed a unique strategy in which the exocyclic epoxide was generated as the initial stereocenter (Scheme 15) [12][13]. The Sharpless asymmetric
  • epoxidation [37] of 5-methyl-2-methylene-4-penten-1-ol gave the epoxyalcohol 92 in 94% ee, which was oxidized to the aldehyde 93. While the addition of the lithium salt of methyl propynoate proceeded in a nondiastereoselective fashion, the use of a zirconium/silver-mediated alkynylation gave the alcohol 94
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Published 13 Aug 2020

Recent synthesis of thietanes

  • Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

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Published 22 Jun 2020

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

  • Sambasivarao Kotha,
  • Milind Meshram and
  • Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

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  • 108 (89%). Then, MnO2 oxidation of compound 108 offered the keto derivative in 90% yield. Corey–Bakshi–Shibata (CBS) reduction of the resulting keto derivative produced the hydroxy compound 109 (85%, ee 98%). Eventually, hydroxy olefin 109 was subjected to Sharpless asymmetric epoxidation to generate
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Published 21 Sep 2018

Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis

  • Raju Cheerlavancha,
  • Ahmed Ahmed,
  • Yun Cheuk Leung,
  • Aggie Lawer,
  • Qing-Quan Liu,
  • Marina Cagnes,
  • Hee-Chan Jang,
  • Xiang-Guo Hu and
  • Luke Hunter

Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228

Graphical Abstract
  • an attempted Sharpless asymmetric epoxidation reaction using (+)-DET (Scheme 3); however, none of the desired product 28a was observed in this case, presumably due to a substrate/catalyst mismatch effect. Therefore, the epoxidation reaction was re-attempted using (−)-DET (Scheme 3); this successfully
  • 27 (Scheme 3). Compound 35 was carried through the same set of reactions that were described previously for substrate 27 (Scheme 3). Thus, 35 underwent a cross metathesis reaction to furnish 36 in good yield (Scheme 4). Compound 36 then became the substrate for a Sharpless asymmetric epoxidation
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Published 01 Nov 2017

The chemistry and biology of mycolactones

  • Matthias Gehringer and
  • Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

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Published 11 Aug 2017

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

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  •  1, method 1). For this purpose, the necessary epoxide 6 could be obtained from the parent E-allylic alcohol through Sharpless asymmetric epoxidation (SAE) [11]. However, the corresponding parent Z-allylic alcohol appears to be not suitable to provide 7 under SAE conditions [20]. This has eliminated
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Published 21 Mar 2017

Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

  • Pramod R. Markad,
  • Navanath Kumbhar and
  • Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

Graphical Abstract
  • -glucose derived alcohol 3 in 13 steps and 14% overall yield. Thus, the Sharpless asymmetric epoxidation of allyl alcohol 7 followed by trimethyl borate mediated regio-selective oxirane ring opening with azide, afforded azido diol 10. The acid-catalyzed 1,2-acetonide ring opening in 10 concomitantly led to
  • oxocarbenium ion at C1 to which concomitant addition of a hydroxy group (present in the side chain at C3) will give the requisite pyranose ring skeleton. Intermediate B could be derived from the allyl alcohol C by using the Sharpless asymmetric epoxidation followed by regioselective epoxide ring opening with
  • Sharpless asymmetric epoxidation (SAE) [16][17]. Thus, allyl alcohol 7 was subjected for SAE first using (+)-DET that afforded a diastereomeric mixture of epoxy alcohols 8 and 9 in the ratio of 88:12 (based on the 1H NMR analysis) in 85% yield. Similarly, use of (–)-DET in SAE afforded epoxide 8 and 9 in
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Published 05 Aug 2016

Selective bromochlorination of a homoallylic alcohol for the total synthesis of (−)-anverene

  • Frederick J. Seidl and
  • Noah Z. Burns

Beilstein J. Org. Chem. 2016, 12, 1361–1365, doi:10.3762/bjoc.12.129

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  • ; total synthesis; Introduction The directed enantioselective functionalization of olefins is an extremely powerful tool in synthesis. A preeminent example is the Sharpless asymmetric epoxidation (SAE), which has been featured in countless syntheses of enantioenriched small molecules [1][2]. While the
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Published 01 Jul 2016

A protecting group-free synthesis of the Colorado potato beetle pheromone

  • Zhongtao Wu,
  • Manuel Jäger,
  • Jeffrey Buter and
  • Adriaan J. Minnaard

Beilstein J. Org. Chem. 2013, 9, 2374–2377, doi:10.3762/bjoc.9.273

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  • decemlineata, has been developed based on a Sharpless asymmetric epoxidation in combination with a chemoselective alcohol oxidation using catalytic [(neocuproine)PdOAc]2OTf2. Employing this approach, the pheromone was synthesized in 3 steps, 80% yield and 86% ee from geraniol. Keywords: aggregation pheromone
  • synthesis of the Colorado potato beetle pheromone (Scheme 2). An additional challenge was the presence of an alkene in the substrate, as the orthogonality of 2-catalyzed alcohol oxidations with alkenes had not been studied. In our approach, Sharpless asymmetric epoxidation of readily available geraniol or
  • the literature [8][9]. Starting from nerol, Sharpless asymmetric epoxidation afforded the epoxide (2S,3R)-4 in a disappointing 74% ee, a result which is nevertheless in accordance with the reported values: 70–94% [25][26][27][28][29][30] (Scheme 4). Applying the same ring-opening reaction to epoxide
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Published 06 Nov 2013

Can we measure catalyst efficiency in asymmetric chemical reactions? A theoretical approach

  • Shaimaa El-Fayyoumy,
  • Matthew H. Todd and
  • Christopher J. Richards

Beilstein J. Org. Chem. 2009, 5, No. 67, doi:10.3762/bjoc.5.67

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  • material, or a reaction for which there currently exist few alternatives. The Sharpless Asymmetric Epoxidation, for example, suffers from a low ACE. From an academic viewpoint, this transformation is nevertheless important because of the breakthrough nature of this relatively low cost reaction. It has few
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Published 19 Nov 2009

A short stereoselective synthesis of (+)-(6R,2′S)-cryptocaryalactone via ring- closing metathesis

  • Palakodety Radha Krishna,
  • Krishnarao Lopinti and
  • K. L. N. Reddy

Beilstein J. Org. Chem. 2009, 5, No. 14, doi:10.3762/bjoc.5.14

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  • : Carreira asymmetric alkynylation; Cryptocarya bourdilloni GAMB (Lauraceae); ring-closing metathesis; Sharpless asymmetric epoxidation; Introduction Natural products play an important role in the development of drugs and mankind has always taken advantage of nature as pharmacy: approximately 40% of the
  • alcohol that was obtained from a regioselective ring-opening reaction of 2,3-epoxy alcohol 8. The known 2,3-epoxy alcohol 8 was synthesized from the corresponding dienyl alcohol by the well-established Sharpless asymmetric epoxidation conditions in >94% ee as described in literature [38][39]. Compound 8
  • wherein a chiral 2,3-epoxy alcohol was the starting material and Sharpless asymmetric epoxidation and Carreira asymmetric alkynylation were used as key steps for generating unambiguous assigned stereocenters. More importantly, the Grubbs’ ring-closing metathesis protocol was applied to construct the final
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Published 24 Apr 2009

Recent progress on the total synthesis of acetogenins from Annonaceae

  • Nianguang Li,
  • Zhihao Shi,
  • Yuping Tang,
  • Jianwei Chen and
  • Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

Graphical Abstract
  • materials (e.g. amino acids, sugars, tartaric acid, etc.) or on asymmetric reactions {e.g. Sharpless asymmetric epoxidation (AE), Sharpless asymmetric dihydroxylation (AD), diastereoselective Williamson etherification, etc.}. Semi-synthesis of natural ACGs as well as derivatised ACGs (e.g. amines, esters
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Published 05 Dec 2008
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