Search results

Search for "Mitsunobu" in Full Text gives 123 result(s) in Beilstein Journal of Organic Chemistry.

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

Graphical Abstract
  • using Mitsunobu reagents Over the last 50 years the Mitsunobu reaction [102] has developed into one of the mainstays in the organic chemist’s toolbox. It has such far reaching potential that it or partial variants of the procedure can now be utilized in glycosylation reactions of unprotected and
  • ]. 5.1.2 Esterification of benzoic acids with glycosyl donors: Again in 2015 Kawabata and co-workers applied the Mitsunobu reaction to an unprotected and unactivated donor in the first step of the total synthesis of two ellagitannins. Using a moderate excess
PDF
Album
Review
Published 27 Jun 2017

DMAP-assisted sulfonylation as an efficient step for the methylation of primary amine motifs on solid support

  • Johnny N. Naoum,
  • Koushik Chandra,
  • Dorit Shemesh,
  • R. Benny Gerber,
  • Chaim Gilon and
  • Mattan Hurevich

Beilstein J. Org. Chem. 2017, 13, 806–816, doi:10.3762/bjoc.13.81

Graphical Abstract
  • of over-methylated amines. The Mitsunobu–Fukuyama reaction was used for the conversion of primary amines to secondary mono-methylated amines in solution using an alcohol and via temporary protection of the amino group to avoid over methylation [17][18][19][20][21]. This method relies on the
  • introduction of the o- or p-nitrobenzenesulfonyl groups to primary amines in the first step. The semi-protected sulfonamides can then undergo a selective mono-methylation via Mitsunobu reaction or by direct methylation. The reaction is completed by the selective removal of the sulfonamide group. Miller and
PDF
Album
Supp Info
Full Research Paper
Published 03 May 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

Graphical Abstract
  • the possibility of obtaining 2 via intramolecular epoxide ring-opening of 7 (Scheme 1, method 2). Consequently, an alternative pathway involving the Mitsunobu inversion of 9 (obtained by intramolecular epoxide ring-opening of 8 which is the enantiomer of 6) has been followed to obtain 2 (Scheme 1
  • , respectively, in 93% yield. It is to be mention that the NMR spectra and specific rotations of 2 and 29 matched with those reported in the literature [11][14][15]. For the synthesis of compound 3, stereoisomer 29 was subjected to classical two-step Mitsunobu inversion protocol which was successful but poor
  • -hydroxy-α-tosyloxy esters 24 and 25. Speculation of simultaneous epoxidation/epoxide-ring opening. Synthesis of chroman diols 2 and 29, respectively. Conversion of 32 into 3 via Mitsunobu inversion. Synthesis of chroman epoxide 5. Supporting Information Supporting Information File 228: Experimental
PDF
Album
Supp Info
Letter
Published 21 Mar 2017

Revaluation of biomass-derived furfuryl alcohol derivatives for the synthesis of carbocyclic nucleoside phosphonate analogues

  • Bemba Sidi Mohamed,
  • Christian Périgaud and
  • Christophe Mathé

Beilstein J. Org. Chem. 2017, 13, 251–256, doi:10.3762/bjoc.13.28

Graphical Abstract
  • carbocyclic nucleoside methylphosphonate analogues bearing purine bases (adenine and guanine) was accomplished using bio-sourced furfuryl alcohol derivatives. All compounds were prepared using a Mitsunobu coupling between the heterocyclic base and an appropriate carbocyclic precursor. After deprotection, the
  • -hydroxycyclopentyl acetate (5) and (+/−)-1-((dimethoxyphosphoryl)methyl)-4-hydroxycyclopent-2-en-1-yl acetate (7). The protection of the tertiary hydroxy groups was necessary in order to avoid competing side reactions during the coupling reaction under Mitsunobu conditions [10]. Compounds (+/−)-5 and (+/−)-7 were
  • used as suitable precursors for the synthesis of the target carbocyclic methylphosphonates. Synthesis of cyclopentyl carbocyclic methylphosphonates (+/−)-12 and (+/−)-13 The synthesis of the target compounds was accomplished using a Mitsunobu reaction (Scheme 2) [11]. The coupling of (+/−)-5 with bis
PDF
Album
Supp Info
Full Research Paper
Published 09 Feb 2017

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

Graphical Abstract
  • most likely unstable, we decided to deprotect 20 directly before the planned one-pot procedure and use it without purification. In order to obtain (R)-10, we decided to inverse the configuration at the free hydroxy group in allylic alcohol 19 by Mitsunobu reaction. Despite the fact that the use of
  • allylic alcohols as substrates in Mitsunobu reactions can be a challenging task, some successful examples can be found in the literature [49][50]. However, the reaction with benzoic acid did not proceed at all, whereas application of p-nitrobenzoic acid yielded a complicated mixture of products. Therefore
PDF
Album
Supp Info
Full Research Paper
Published 01 Dec 2016

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

Graphical Abstract
  • protecting group manipulation and installation of the guanidine using S-methylisothiourea 33 (Scheme 5). Mitsunobu cyclisation followed by deprotection and oxidation afforded the azido acids 38 and 39 in 40% yield over 8 steps from amino azides 36 and 37. Synthesis of β-hydroxyenduracididine by Nieuwenhze et
  • the guanidine group using isothiourea 33 before cyclisation was effected using Mitsunobu conditions. After a six-step conversion of alkene 44 to nosyl intermediate 42, the synthesis diverged to access both C-2 diastereomers. Displacement of nosylate 42 with sodium azide followed by reduction and amine
PDF
Album
Review
Published 07 Nov 2016

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

Graphical Abstract
  • to 64%. The remaining two stereoisomers, (−)-1b and (+)-1d, were obtained from (−)-1a and (+)-1c in 71 and 68% yield, respectively, by a two-reaction sequence, in which a Mitsunobu inversion of configuration at C-5 was the key step. Keywords: antiulcer drug; chiral resolution; rosaprostol
  • yield of the synthesis of (−)-1a from (+)-3 involving this alternative procedure was increased to 64%. With the two rosaprostol stereoisomers 1a and 1c in hand, the synthesis of the remaining two stereoisomers 1b and 1d was readily accomplished with a Mitsunobu reaction [28] inverting the configuration
  • at C-5. In fact, 1a and 1c were obtained through a two-step sequence starting with the methylation of (−)-1a and (+)-1c followed by a one-pot Mitsunobu esterification–hydrolysis as shown in Scheme 6. In detail, treatment of rosaprostols (−)-1a and (+)-1c with diazomethane gave the corresponding
PDF
Album
Supp Info
Full Research Paper
Published 21 Oct 2016

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
  • ] (Scheme 2). Selective protection of the C5 primary hydroxy group as PMP ether using p-methoxyphenol under Mitsunobu reaction conditions afforded 4 that on benzylation of the C3 hydroxy group (NaH and benzyl bromide in DMF) gave compound 5. Upjohn dihydroxylation of 5 using K2OsO4·2H2O followed by
PDF
Album
Supp Info
Full Research Paper
Published 05 Aug 2016

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

  • Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

Graphical Abstract
  • . Some of these post-MCR transformations are: intramolecular cycloaddition reactions, Knoevenagel condensations, metathesis reactions, aza-Wittig reactions, Mitsunobu reactions, etc. [21]. Up to now, two review articles have been reported on azaheterocyclic phosphonates [22][23], but no overview article
PDF
Album
Review
Published 21 Jun 2016

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

  • Barry M. Trost,
  • Michael C. Ryan and
  • Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

Graphical Abstract
  • bicycloisomerization reaction can be readily accessed in two steps. Alkylation of a secondary propargylamide can be achieved by sodium hydride deprotonation of its acidic proton and SN2 substitution of a substituted propargyl bromide (Scheme 5a). Alternatively, the same propargylamide can be alkylated under Mitsunobu
PDF
Album
Supp Info
Full Research Paper
Published 07 Jun 2016

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

  • Daniel Wiegmann,
  • Stefan Koppermann,
  • Marius Wirth,
  • Giuliana Niro,
  • Kristin Leyerer and
  • Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

Graphical Abstract
  • muraymycins (Scheme 5) [98]. A fully protected ureidomuraymycidine tripeptide was prepared through lactone opening followed by urea formation and a final Mitsunobu ring closure as key steps. A Strecker reaction of the benzylimine 34 followed by several steps afforded the alcohol 35. A thermal lactonisation as
  • obtained precursor 42 was treated with DIAD and PPh3 in a final step for an intramolecular Mitsunobu ring closure to finish the synthesis of the fully protected ureidomuraymycidine 43 (Scheme 5) [98]. In 2010, Ducho et al. reported an alternative synthesis of the naturally occurring uridine-derived
PDF
Album
Review
Published 22 Apr 2016

Asymmetric α-amination of 3-substituted oxindoles using chiral bifunctional phosphine catalysts

  • Qiao-Wen Jin,
  • Zhuo Chai,
  • You-Ming Huang,
  • Gang Zou and
  • Gang Zhao

Beilstein J. Org. Chem. 2016, 12, 725–731, doi:10.3762/bjoc.12.72

Graphical Abstract
  • Mannich-type reaction. As an extension of this work, we then wondered if other electrophilic partners instead of methyl acrylate could be used to generate similar catalytically active species in situ. Also inspired by the Mitsunobu reaction [43], we reported herein the reaction of azodicarboxylates with 3
  • spectra research in CD2Cl2. The mimetic activation mode of Mitsunobu reaction. Scale-up of the reaction and deprotection of the product. Proposed transition-state model. Catalyst screening. Optimization of conditions. Substrate scope. Supporting Information Supporting Information File 32: Experimental
PDF
Album
Supp Info
Full Research Paper
Published 15 Apr 2016

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

  • Guozheng Huang,
  • Simon Schramm,
  • Jörg Heilmann,
  • David Biedermann,
  • Vladimír Křen and
  • Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

Graphical Abstract
  • , Prague 4, CZ-14220, Czech Republic 10.3762/bjoc.12.66 Abstract Various Mitsunobu conditions were investigated for a series of flavonolignans (silybin A, silybin B, isosilybin A, and silychristin A) to achieve either selective esterification in position C-23 or dehydration in a one-pot reaction yielding
  • the biologically important enantiomers of hydnocarpin D, hydnocarpin and isohydnocarpin, respectively. This represents the only one-pot semi-synthetic method to access these flavonolignans in high yields. Keywords: dehydration; flavonoid; hydnocarpin; Mitsunobu; silybin; Introduction Flavonolignans
  • ; 5% catalyzed by horseradish peroxidase) [14]. To study the biological activities of hydnocarpin-type compounds, a new and robust method for their preparation is required. It is known that elimination can occur in some cases as a side reaction in Mitsunobu esterifications with structurally hindered
PDF
Album
Supp Info
Full Research Paper
Published 08 Apr 2016

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

  • Tatjana Huber,
  • Lara Weisheit and
  • Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

Graphical Abstract
  • literature-known procedure [47]. Regioselective reduction with sodium borohydride, followed by dehydration under Mitsunobu conditions and silylation of the tertiary alcohol furnished trimethylsiloxy ketone 78. The ketone functionality was then diastereoselectively reduced under Corey–Bakshi–Shibata
PDF
Album
Review
Published 10 Dec 2015

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

  • Marco G. Rigamonti and
  • Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

Graphical Abstract
  • ) stereogenic center by means of a Mitsunobu reaction, followed by transesterification of the ester to give 4 (Scheme 1). (S)-Isopulegone was prepared by Jones oxidation of (−)-isopulegol following a reported procedure [14]; but on a large scale we have observed that a partial loss of the optical purity of the
  • . The best performances were obtained with the Thermoanaerobium brokii ADH; but even if the de was excellent (>99%) the conversion was still too low (about 36% by GC) to be really exploited on a preparative scale. Finally, we tried the Mitsunobu reaction, which gave the best results (method D) [19
PDF
Album
Supp Info
Full Research Paper
Published 05 Nov 2015

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

  • Marcus Baumann and
  • Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

Graphical Abstract
  • , however, insufficient deprotonation of the alcohol 50 under flow conditions (NaHMDS or BEMP instead of using a suspension of NaH as used in batch) required a modification to the planned approach. To this end a Mitsunobu protocol based on the orchestrated mixing of four reagent streams (50, 54 and reagents
PDF
Album
Review
Published 17 Jul 2015

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

  • Paweł Borowiecki,
  • Daniel Paprocki and
  • Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

Graphical Abstract
  • identified as a key step in optimizing the process to avoid racemization. To save one step less, we initiated our efforts by direct transformation of the sec-alcohol functionality in afore-obtained compound (±)-3 under modified Mitsunobu [78][79] reaction conditions using Ph3P (1.1 equiv), DEAD (1.1 equiv
  • ), and the respective amine (1 equiv of Et2NH or Me2NH) conducted in dry THF. Since the Mitsunobu condensation protocol is considered as particularly attractive due to the superior reactivity of the in situ-generated corresponding oxyphosphonium intermediate on nucleophilic substitution, we envisioned
  • disappointment, none of these attempts led to success. When Mitsunobu chemistry fails, a hydroxy group inversion by tosylation and displacement using amine was performed. Unfortunately, attempts to carry out the reaction at higher temperature led to complete decomposition of the tosylate substrate. In the
PDF
Album
Supp Info
Full Research Paper
Published 18 Dec 2014

Synthesis of phosphoramidites of isoGNA, an isomer of glycerol nucleic acid

  • Keunsoo Kim,
  • Venkateshwarlu Punna,
  • Phaneendrasai Karri and
  • Ramanarayanan Krishnamurthy

Beilstein J. Org. Chem. 2014, 10, 2131–2138, doi:10.3762/bjoc.10.220

Graphical Abstract
  • for the introduction of the canonical nucleobases by a SN2 displacement reaction. At this point, we chose the Mitsunobu reaction (Scheme 1), which has been widely employed [16]. The reaction with the N3-benzoyl protected thymine delivered 5 in good yield. However, the reaction with N6-benzoyladenine
  • protecting group approach. We silylated 1 to afford 8 whose ketal was deprotected followed by tritylation to give the derivative 10, which is expected to be suited for the introduction of nucleobases by an SN2 reaction (Scheme 2). Once again, the Mitsunobu reaction with thymine proceeded smoothly. However
  • yield 16. The use of 16 in the subsequent Mitsunobu reaction afforded 68% of the desired product 17. With derivatives 11 and 17 in hand we proceeded to prepare the corresponding phosphoramidite derivatives 13 and 19, respectively, under standard conditions as outlined in Scheme 2. We proceeded to
PDF
Album
Supp Info
Full Research Paper
Published 08 Sep 2014

A new charge-tagged proline-based organocatalyst for mechanistic studies using electrospray mass spectrometry

  • J. Alexander Willms,
  • Rita Beel,
  • Martin L. Schmidt,
  • Christian Mundt and
  • Marianne Engeser

Beilstein J. Org. Chem. 2014, 10, 2027–2037, doi:10.3762/bjoc.10.211

Graphical Abstract
  • ). An SN2 reaction with 5 [55] led to 8. We abandoned our initial shorter synthetic route based on a Mitsunobu reaction leading from 6 directly to 8 due to severe purification difficulties. Compound 8 could be charge-tagged to 9 using ethyl bromide. Finally, the free catalyst 1 was obtained by acidic
PDF
Album
Full Research Paper
Published 28 Aug 2014

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

Graphical Abstract
  • compounds, those with a C–O–N bond are less common. Typically the latter are synthesized by the alkylation of BtOH with alkyl halides [17][18], quaternary alkyl ammonium salts [19], or via a Mitsunobu reaction (Scheme 1) [20]. Herein, we report a facile approach to 1-alkoxy-1H-benzo- (Bt-OR) and 7
PDF
Album
Supp Info
Full Research Paper
Published 19 Aug 2014

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

  • Thilo Focken and
  • Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

Graphical Abstract
  • work-up provided alcohol 141. Coupling under Mitsunobu conditions with an appropriate alcohol, e.g., 3-hydroxypyridine, reduction of the tert-butyl ester with DIBAL-H, and treatment with TBS triflate gave silyl ether 142. Hydrogenolysis of 142 using Pd/BaSO4 produced the free aziridine, which was then
PDF
Album
Review
Published 13 Aug 2014

Efficient routes toward the synthesis of the D-rhamno-trisaccharide related to the A-band polysaccharide of Pseudomonas aeruginosa

  • Aritra Chaudhury,
  • Sajal K. Maity and
  • Rina Ghosh

Beilstein J. Org. Chem. 2014, 10, 1488–1494, doi:10.3762/bjoc.10.153

Graphical Abstract
  • synthesis of monomeric D-rhamnose has been highly streamlined by Roy et al. in 2007 [26], and further improvement on this method was reported by Kiefel et al. in 2011 [27]. However, the deoxygenation protocol involving halogenation under Mitsunobu conditions was found to be inefficient when applied to
PDF
Album
Supp Info
Full Research Paper
Published 01 Jul 2014

Rasta resin–triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions

  • Xuanshu Xia and
  • Patrick H. Toy

Beilstein J. Org. Chem. 2014, 10, 1397–1405, doi:10.3762/bjoc.10.143

Graphical Abstract
  • ; polymer-supported reagent; rasta resin; triphenylphosphine oxide; Introduction One of the major drawbacks of the Wittig [1] and Mitsunobu [2][3] reactions is that they result in the formation of a stoichiometric quantity of triphenylphosphine oxide (1) as a byproduct. From an atom economy perspective
PDF
Album
Supp Info
Letter
Published 20 Jun 2014

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

Graphical Abstract
  • both alcohols showed a diastereomeric purity of >99% by 1H NMR. Mitsunobu reaction on the secondary alcohols using DEAD or DIAD did not provide the desired azides [42][43] nor did a one-pot Appel reaction/nucleophilic substitution/Staudinger reaction protocol involving a double inversion of
PDF
Album
Supp Info
Letter
Published 11 Jun 2014

4-Hydroxy-6-alkyl-2-pyrones as nucleophilic coupling partners in Mitsunobu reactions and oxa-Michael additions

  • Michael J. Burns,
  • Thomas O. Ronson,
  • Richard J. K. Taylor and
  • Ian J. S. Fairlamb

Beilstein J. Org. Chem. 2014, 10, 1159–1165, doi:10.3762/bjoc.10.116

Graphical Abstract
  • using them as nucleophilic partners in oxa-Michael additions and the Mitsunobu reaction. The reactions proceed in moderate to excellent yields on a range of substrates containing useful functionality. The reactions serve as practical and valuable synthetic methods to construct complex 2-pyronyl ethers
  • , which are found embedded in a number of natural products. Keywords: heterocycles; Mitsunobu reaction; oxa-Michael addition; 2-pyrone; vinyl ethers; Introduction The 2-pyrone motif is a prevalent structural feature of many complex natural products and biologically active compounds [1][2]. Various
  • degradation under harsh conditions, representing an interesting synthetic chemistry challenge to address. The ability to install more complex functionality on the hydroxy group of 6-alkyl-4-hydroxy-2-pyrones would be of considerable synthetic value. The Mitsunobu reaction is a well-established, widely used
PDF
Album
Supp Info
Full Research Paper
Published 20 May 2014
Other Beilstein-Institut Open Science Activities