- Asymmetric azidohydroxylation of styrene derivatives mediated by a biomimetic styrene monooxygenase enzymatic cascade
-
Enantioenriched azido alcohols are precursors for valuable chiral aziridines and 1,2-amino alcohols, however their chiral substituted analogues are difficult to access. We established a cascade for the asymmetric azidohydroxylation of styrene derivatives leading to chiral substituted 1,2-azido alcohols via enzymatic asymmetric epoxidation, followed by regioselective azidolysis, affording the azido alcohols with up to two contiguous stereogenic centers. A newly isolated two-component flavoprotein styrene monooxygenase StyA proved to be highly selective for epoxidation with a nicotinamide coenzyme biomimetic as a practical reductant. Coupled with azide as a nucleophile for regioselective ring opening, this chemo-enzymatic cascade produced highly enantioenriched aromatic α-azido alcohols with up to >99% conversion. A bi-enzymatic counterpart with halohydrin dehalogenase-catalyzed azidolysis afforded the alternative β-azido alcohol isomers with up to 94% diastereomeric excess. We anticipate our biocatalytic cascade to be a starting point for more practical production of these chiral compounds with two-component flavoprotein monooxygenases.
- Franssen, Maurice C. R.,Hollmann, Frank,Martínez-Montero, Lía,Paul, Caroline E.,Süss, Philipp,Schallmey, Anett,Tischler, Dirk
-
-
Read Online
- Preparation of Vicinal Azidohydrins by Reaction of Oxiranes with Triethylaluminium/Hydrogen Azide
-
A novel, mild, and highly stereoselective transformation of epoxides to azidohydrins by treatment with Et3Al/HN3 in toluene is described.As an example for the versatility of the reaction, a polyfunctional compound, 14,15-epoxy-14,15-dihydromilbemycin D (1), was transformed to 14-azido-14,15-dihydro-15-hydroxymilbemycin D (2) in 61 percent yield.
- Mereyala, Hari Babu,Frei, Bruno
-
-
Read Online
- Regioselective azidolysis of epoxides catalyzed with Ce(IV)
-
Regioselective conversion of epoxides to 1,2-azidoalcohols was performed efficiently with sodium azide in t-butanol and in the presence of catalytic amounts of Ce(IV) as ceric ammonium nitrate (CAN).
- Iranpoor, Nasser,Kazemi, Foad
-
-
Read Online
- Efficient one-pot click synthesis of β-hydroxy-1,2,3-triazoles catalyzed by copper(i)@phosphorated SiO2via multicomponent reaction in aqueous media
-
Copper(i)-modified SiO2, in particular Cu(i)@phosphorated SiO2 (CPSi) has been found to effectively catalyze the multi-component synthesis of β-hydroxy-1,2,3-triazoles from a variety of epoxides and alkynes in water. This novel heter
- Naeimi, Hossein,Nejadshafiee, Vajihe
-
-
Read Online
- Highly α-position regioselective ring-opening of epoxides catalyzed by halohydrin dehalogenase from: Ilumatobacter coccineus: A biocatalytic approach to 2-azido-2-aryl-1-ols
-
Halohydrin dehalogenases are usually recognized as strict β-position regioselective enzymes in the nucleophile-mediated ring-opening of epoxides. Here we found the HheG from Ilumatobacter coccineus exhibited excellent α-position regioselectivity in the az
- An, Miao,Liu, Wanyi,Zhou, Xiaoying,Ma, Ran,Wang, Huihui,Cui, Baodong,Han, Wenyong,Wan, Nanwei,Chen, Yongzheng
-
p. 16418 - 16422
(2019/06/17)
-
- CuO supported 1-methyl-3-(3-(trimethoxysilyl) propyl) imidazolium chloride (MTMSP-Im/Cl) nanoparticles as an efficient simple heterogeneous catalysts for synthesis of β-azido alcohols
-
In the present study, CuO supported 1-methyl-3-(3-(trimethoxysilyl) propyl) imidazolium chloride (MTMSP-Im/Cl) is synthesized as a novel, efficient and eco-friendly heterogeneous nanocatalyst. This nanocatalyst was applied for selective ring opening of ep
- Fadavipoor,Badri,Kiasat,Sanaeishoar
-
p. 1451 - 1458
(2019/06/13)
-
- Iron-Catalysed Remote C(sp3)?H Azidation of O-Acyl Oximes and N-Acyloxy Imidates Enabled by 1,5-Hydrogen Atom Transfer of Iminyl and Imidate Radicals: Synthesis of γ-Azido Ketones and β-Azido Alcohols
-
In the presence of a catalytic amount of iron(III) acetylacetonate [Fe(acac)3], the reaction of structurally diverse ketoxime esters with trimethylsilyl azide (TMSN3) afforded γ-azido ketones in good to excellent yields. This unprecedented distal γ-C(sp3)?H bond azidation reaction went through a sequence of reductive generation of an iminyl radical, 1,5-hydrogen atom transfer (1,5-HAT) and iron-mediated redox azido transfer to the translocated carbon radical. TMSN3 served not only as a nitrogen source to functionalise the unactivated C(sp3)?H bond, but also as a reductant to generate the catalytically active FeII species in situ. Based on the same principle, a novel β-C(sp3)?H functionalisation of alcohols via N-acyloxy imidates was subsequently realised, leading, after hydrolysis of the resulting ester, to β-azido alcohols, which are important building blocks in organic and medicinal chemistry.
- Torres-Ochoa, Rubén O.,Leclair, Alexandre,Wang, Qian,Zhu, Jieping
-
supporting information
p. 9477 - 9484
(2019/05/21)
-
- Montmorillonite K10 catalyzed highly regioselective azidolysis of epoxides: A short and efficient synthesis of phenylglycine
-
A series of β‐hydroxyazides were effectively synthesized from the regioselective ring opening of epoxides by sodium azide using montmorillonite K10 as a novel heterogeneous catalyst in aqueous acetonitrile in good to excellent yields. The utility of this method has been demonstrated by achieving a short synthesis of phenylglycine in 33.5% overall yield.
- Ch Ghosh, Keshab,Banerjee, Isita,Sinha, Surajit
-
supporting information
p. 2923 - 2934
(2018/12/04)
-
- Synthesis and characterization of supramolecule grafted on modified magnetic nanoparticles: new hybrid organic–inorganic phase transfer catalyst
-
Abstract: In this study, for the first time, calix[4]resorcinarene was grafted on the silica-coated magnetic nanoparticles (MNPs-Si) which efficiently catalyze one-pot epoxide ring opening reaction in excellent yields in a very short reaction time. Variou
- Mouradzadegun, Arash,Boroon, Sadjad,Fard, Pegah Kazemian
-
p. 367 - 374
(2017/02/10)
-
- Acetic acid functionalized ionic liquid systems: An efficient and recyclable catalyst for the regioselective ring opening of epoxides with NaN3
-
In the present study, an environmentally benign, efficient, and solvent-free procedure was developed for the synthesis of 1,2-azidoalcohols by the regioselective ring opening of some epoxides with sodium azide (NaN3) in the presence of an aceti
- Rezayati, Sobhan,Salehi, Elaheh,Hajinasiri, Rahimeh,Afshari Sharif Abad, Saeid
-
p. 554 - 558
(2017/05/19)
-
- Synthesis and characterization of a novel nanomagnetic phase-transfer catalyst and its application to regioselective synthesis of β-azido and β-nitro alcohols in water
-
Immobilization of polyethylene glycol-substituted 1-methylimidazolium bromide on the surface of magnetic Fe3O4 nanoparticles through hexane-1,6-diyldicarbamate linker afforded a powerful and reusable heterogeneous phase-transfer cata
- Ayashi,Fallah-Mehrjardi,Kiasat
-
p. 846 - 852
(2017/08/02)
-
- Hydrotrope promoted in situ azidonation followed by copper catalyzed regioselective synthesis of β-hydroxytriazoles
-
Abstract: The rapid method for the synthesis of organic azides was achieved by employing azide acceptors such as halides, epoxides and pseudohalides like diazonium salts and aryl boronic acids in hydrotropic media. In extension, the sequential multicomponent reaction of epoxides, azide and alkynes using copper catalysis has been discussed. The reaction proceeds via the in situ generation of azido-alcohol followed by synthesis of chiral β-hydroxytriazoles. This [3?+?2] cycloaddition reaction of azide and alkyne using copper catalysis serves as a green and efficient protocol in “Click Chemistry”. The nucleophilic addition of azide to epoxide and alkyne-azide cycloaddition is the two simultaneous regioselective click reactions observed in the proposed method. Graphical Abstract: [Figure not available: see fulltext.].
- Patil, Amol,Salunkhe, Rajashri
-
p. 4175 - 4187
(2017/06/20)
-
- Fe3O4 nanoparticle-bonded β-cyclodextrin as an efficient and magnetically retrievable catalyst for the preparation of β-azido alcohols and β-hydroxy thiocyanate
-
A novel Fe3O4 nanoparticle-bonded β-cyclodextrin (β-CD@MNP) has been synthesized and characterized by scanning electron microscopy, vibrating sample magnetometry, and thermogravimetric analysis. It is found that the nanoparticles can
- Sayyahi, Soheil,Mozafari, Sara,Saghanezhad, Seyyed Jafar
-
p. 511 - 518
(2016/04/26)
-
- 1-(1-Alkylsulfonic)-3-methylimidazolium chloride as a reusable Br?nsted acid catalyst for the regioselective azidolysis of epoxides under solvent-free conditions
-
In this study, 1-(1-alkylsulfonic)-3-methylimidazolium chloride as a new, green, and reusable Br?nsted acid catalyst was prepared. In this protocol, we used for the regioselective ring-opening reactions of various epoxiodes with sodium azide to afford the
- Rezayati, Sobhan,Nezhad, Eshagh Rezaee,Hajinasiri, Rahimeh
-
p. 974 - 978
(2016/06/13)
-
- Azidolysis of epoxides catalysed by the halohydrin dehalogenase from Arthrobacter sp. AD2 and a mutant with enhanced enantioselectivity: an (S)-selective HHDH
-
Halohydrin dehalogenase from Arthrobacter sp. AD2 catalysed azidolysis of epoxides with high regioselectivity and low to moderate (S)-enantioselectivity (E?=?1–16). Mutation of the asparagine 178 to alanine (N178A) showed increased enantioselectivity towards styrene oxide derivatives and glycidyl ethers. Conversion of aromatic epoxides was catalysed by HheA-N178A with complete enantioselectivity, however the regioselectivity was reduced. As a result of the enzyme-catalysed reaction, enantiomerically pure (S)-β-azido alcohols and (R)-α-azido alcohols (ee???99%) were obtained.
- Mikleu?evi?, Ana,Primo?i?, Ines,Hrenar, Tomica,Salopek-Sondi, Branka,Tang, Lixia,Elenkov, Maja Majeri?
-
p. 930 - 935
(2016/09/13)
-
- Synthesis and characterization of a novel nano-Fe3O4-copoly[(styrene/acrylic acid)/grafted ethylene oxide and its application as a magnetic and recyclable phase-transfer catalyst in the preparation of β-azido alcohols and β-nitro alc
-
A facile method was developed for the synthesis of β-azido alcohols and β-nitro alcohols in the presence of a novel nano-Fe3O4-copoly[(styrene/acrylic acid)/grafted ethylene oxide (nano-Fe3O4-PS-Co-[PAA-g-PEG])
- Kiasat, Ali Reza,Daei, Mina,Saghanezhad, Seyyed Jafar
-
p. 581 - 594
(2016/04/26)
-
- Lanthanide-based coordination polymers as promising heterogeneous catalysts for ring-opening reactions
-
This work presents the synthesis and structural characterization of Eu3+- and Tb3+-based coordination polymers starting from a Co3+-based metalloligand offering appended arylcarboxylic acid groups. Both coordination polymers function as reusable heterogeneous catalysts for ring-opening reactions utilizing amines, alcohols, thiols, and azides as the nucleophiles. The catalytic results illustrate an excellent control over the regioselectivity whereas a filtration test and mechanistic studies substantiate Lewis-acid catalyzed activation of the epoxide during the reaction.
- Kumar, Gulshan,Kumar, Girijesh,Gupta, Rajeev
-
p. 21352 - 21361
(2016/03/08)
-
- Synthesis and characterization of a novel Fe3O4@SiO2/bipyridinium dichloride nanocomposite and its application as a magnetic and recyclable phase-transfer catalyst in the preparation of β-azidoalcohols, β-cyanohydrins, and
-
β-Azidoalcohols, β-cyanohydrins, and β-acetoxy alcohols have been synthesized in the presence of a Fe3O4@SiO2/bipyridinium nanocomposite (Fe3O4@SiO2/BNC) as a novel magnetic and recyclable
- Kiasat, Ali Reza,Chadorian, Fatemeh,Saghanezhad, Seyyed Jafar
-
p. 1297 - 1306
(2015/12/11)
-
- Oxidant controlled regio- and stereodivergent azidohydroxylation of alkenes via I2 catalysis
-
A novel, I2 catalyzed regio- and stereodivergent vicinal azidohydroxylation of alkenes leading to 1,2-azidoalcohols in high yields (up to 92%) and excellent dr (up to 98%) has been developed. This unprecedented transformation employs NaN3 and DMF as N- and O-nucleophiles respectively. The role of DMF as the O-source in the reaction has been unequivocally proven by 18O labelling studies.
- Prasad,Reddi,Sudalai
-
supporting information
p. 10276 - 10279
(2015/06/25)
-
- Facile synthesis of an organic-inorganic nanocomposite, PEG-silica, by sol-gel method; Its characterization and application as an efficient catalyst in regioselective nucleophilic ring opening of epoxides: Preparation of β-azido alcohols and β-cyanohydrin
-
The sol-gel method was used for the synthesis of a PEG-silica hybrid. In order to introduce PEG into the cavities of silica gel, first, the bis(3-trimethoxysilylpropyl)-polyethylene glycol precursor was synthesized by the reaction of 3-chloropropyltrimeth
- Kiasat, Ali Reza,Nazari, Simin,Davarpanah, Jamal
-
p. 124 - 130
(2014/03/21)
-
- Ni2+ supported on hydroxyapatite-core-shell γ-Fe 2O3 nanoparticles: A novel, highly efficient and reusable lewis acid catalyst for the regioselective azidolysis of epoxides in water
-
In this research, Ni2+ supported on hydroxyapatite-core-shell magnetic γ-Fe2O3 nanoparticles (γ-Fe 2O3@HAp-Ni2+) as a novel, efficient, reusable and heterogeneous catalyst was reported. In
- Sajjadifar, Sami,Abbasi, Zahra,Rezaee Nezhad, Eshagh,Moghaddam, Mojtaba Rahimi,Karimian, Saaid,Miri, Sara
-
p. 335 - 340
(2014/04/03)
-
- A hafnium-based metal-organic framework as an efficient and multifunctional catalyst for facile CO2 fixation and regioselective and enantioretentive epoxide activation
-
Porous heterogeneous catalysts play a pivotal role in the chemical industry. Herein a new Hf-based metal-organic framework (Hf-NU-1000) incorporating Hf6 clusters is reported. It demonstrates high catalytic efficiency for the activation of epoxides, facilitating the quantitative chemical fixation of CO2 into five-membered cyclic carbonates under ambient conditions, rendering this material an excellent catalyst. As a multifunctional catalyst, Hf-NU-1000 is also efficient for other epoxide activations, leading to the regioselective and enantioretentive formation of 1,2-bifuctionalized systems via solvolytic nucleophilic ring opening.
- Beyzavi, M. Hassan,Klet, Rachel C.,Tussupbayev, Samat,Borycz, Joshua,Vermeulen, Nicolaas A.,Cramer, Christopher J.,Stoddart, J. Fraser,Hupp, Joseph T.,Farha, Omar K.
-
supporting information
p. 15861 - 15864
(2015/02/19)
-
- A waste-minimized protocol for the preparation of 1,2-azido alcohols and 1,2-amino alcohols
-
Under solvent-free conditions the reaction of epoxides 1a-i with trimethylsilylazide (2) catalyzed by polystiryl-supported fluoride (PS-DABCOF2) has led to the efficient preparation of the corresponding O-TMS protected 1,2-azido alcohols 3a-i that, by treatment with Dowex-H, gave the related 1,2-azido alcohols 4a-i in excellent yields (83-99% and 82-96%, respectively). The use of a flow procedure has allowed us to significantly minimize waste in the preparation of representative 1,2-azido alcohols 4a, 4c and 4i that have been obtained with E-factors of 1.6, 2.1, and 1.9, respectively. The 1,2-amino alcohols 5a, 5c and 5f have been also prepared, in quantitative yields, by reduction of the corresponding O-TMS protected 1,2-azido alcohols 3a, 3c, and 3f by Pd on the Al2O3/HCOOH system.
- Ballerini, Eleonora,Crotti, Paolo,Frau, Ileana,Lanari, Daniela,Pizzo, Ferdinando,Vaccaro, Luigi
-
supporting information
p. 2394 - 2400
(2013/09/12)
-
- Greener and facile aqueous regioselective synthesis of vicinal azidoalcohols using silica-bound 3-((polyethyleneglycol)ethyl)-8-methyl-1H- imidazol-3-ium bromide as a recyclable catalyst
-
An environmentally benign, aqueous synthesis of vicinal azidoalcohols by the regioselective nucleophilic ring opening of epoxides with azide anion using silica-bound 3-((polyethyleneglycol)ethyl)-8-methyl-1H-imidazol-3-ium bromide as an effective heteroge
- Kiasat, Ali Reza,Ayashi, Neda,Fallah-Mehrjardi, Mehdi
-
p. 1175 - 1181
(2013/11/06)
-
- Efficient and regioselective ring-opening of epoxides with alcohols and sodium azide by using catalytic amounts of gacl3/polyvinylpyrrolidone
-
A new polymeric catalyst was prepared by supporting GaCl3 on cross-linked polyvinylpyrrolidone (GaCl3/ PVP). This catalyst was employed for efficient and regioselective ring-opening reaction of epoxides by various alcohols under solvent-free conditions at room temperature. In our procedure, this heterogeneous catalyst was used at neutral and mild reaction conditions to afford high yields of β-alkoxy alcohols. Also, regioselective conversion of epoxides to β-azidohydrines was accomplished by sodium azide in MeOH in the presence of GaCl3/PVP at room temperature. GaCl3/PVP is a non-hygroscopic and recoverable catalyst and is easily separated from reaction mixture by a simple filtration and re-used repeatedly. Also, this catalyst has good handling and can be stored for long time without any reducing of its reactivity.
- Pourali, Ali Reza,Ghayeni, Samaneh,Afghahi, Fatemeh
-
p. 1741 - 1744
(2013/07/26)
-
- Broonsted acidic ionic liquid 1-n-butylimidazolium tetrafluoroborate ([hbim]bf4): A green catalyst and recyclable medium for the azidolysis of epoxides
-
Epoxides undergo rapidly ring opening with sodium azide in [Hbim]BF 4/H2O (2:1) medium, under mild condition to afford the corresponding 2-azidoalchols in high yields. The remarkable features of this procedure are improved yields, en
- Heidarizadeh, Fariba,Zarei, Amanolah
-
experimental part
p. 593 - 598
(2012/09/22)
-
- 1,1'-bis-methyl-3, 3-methylenebisimidazolium dichloride as an efficient phase transfer catalyst for ring opening of epoxides using SCN- and N 3- in water
-
An efficient synthesis of β-azido alcohols and β-hydroxy thiocyanates has been achieved by ring opening of epoxides using 1,1'-bis-methyl-3, 3-methylene-bisimidazolium dichloride as a phase transfer catalyst at room temperature in water. The reaction is r
- Sayyahi, Soheil,Rezaee, Hadis Mohammad,Khalfabadi, Fatemeh Sharifat,Gorjizadeh, Maryam
-
experimental part
p. 396 - 397
(2012/09/21)
-
- Regioselective nucleophilic ring opening of epoxides mediated by novel task-specific ionic liquids; A simple and effective method for production of β-hydroxy azides and β -hydroxy-thiocyanates
-
One third of worldwide chemical products are produced by catalyzed reactions. Most of the imidazolium salts have been introduced as effective and tunable catalysts in many organic transformations. With these regards, in this study, an efficient and enviro
- Fadavipoor, Elham,Nazari, Simin,Saadat, Shervin,Afshari, Mozhgan
-
p. 1520 - 1526
(2013/06/04)
-
- A metal-free, aqueous and general route to 1,5-disubstituted-1,2,3- triazoles: "Reversed regioisomeric" 1,3-dipolar cycloaddition of azides and vinyl sulfones
-
A metal-free, vinyl sulfone-based synthesis of 1,5-disubstituted-1,2,3- triazoles is reported for the first time. These triazoles are easily formed in a regioselective fashion by heating under reflux a mixture of a substituted vinyl sulfone and an organic
- Dey, Santu,Datta, Dhrubajyoti,Pathak, Tanmaya
-
supporting information; experimental part
p. 2521 - 2524
(2011/12/01)
-
- Modular, active, and robust lewis acid catalysts supported on a metal-organic framework
-
Metal-organic frameworks (MOFs) have shown promise as heterogeneous catalysts because of their high crystallinity, uniform pores, and ability to be chemically and physically tuned for specific chemical transformations. One of the challenges with MOF-based
- Tanabe, Kristine K.,Cohen, Seth M.
-
experimental part
p. 6766 - 6774
(2010/09/17)
-
- An environmentally benign catalytic method for efficient and selective nucleophilic ring opening of oxiranes by zirconium tetrakis(dodecyl Sulfate)
-
An operationally simple and environmentally benign protocol for a highly regio- and chemoselective preparation of β-substituted alcohols by means of ring-opening reactions of oxiranes with various aliphatic alcohols, H 2O, NaN3 , and NaCN as nucleophiles in the presence of catalytic amounts of zirconium tetrakis(dodecyl sulfate) as Lewis acid/surfactant-combined catalysts (LASCs) was developed. The high efficiency of the catalyst was confirmed by the high product yields obtained within desired times and, in particularly by the reusability of the ZrIV complex.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Aliabadi, Marzieh
-
scheme or table
p. 405 - 413
(2010/05/19)
-
- Zeo-click chemistry: Copper(I)-zeolite-catalyzed cascade reaction; One-pot epoxide ring-opening and cycloaddition
-
Copper(I)-modified zeolites, especially CuI-USY, proved to be very efficient catalysts in multi-component reactions of epoxides with sodium azide and terminal alkynes. Such catalysts allow highly regio- and stereoselective syntheses ofhydroxyme
- Boningari, Thirupathi,Olmos, Andrea,Reddy, Benjaram M.,Sommer, Jean,Pale, Patrick
-
scheme or table
p. 6338 - 6347
(2011/03/17)
-
- Expedient and rapid synthesis of 1,2,3-triazolo[5,1-c]morpholines through palladium-copper catalysis
-
A one-pot approach using palladium - copper as catalyst has been developed for the synthesis of morpholines fused with 1,2,3-triazole. Good regioselectivity, mild reaction conditions, high yields and short reaction time are the hallmarks of this method.
- Chowdhury, Chinmay,Mukherjee, Sanjukta,Das, Bimolendu,Achari, Basudeb
-
supporting information; scheme or table
p. 3612 - 3615
(2009/09/05)
-
- Green regioselective azidolysis of epoxides catalyzed by multi-site phase-transfer catalyst
-
A facile synthesis of 1,2-azidoalcohols from their epoxides using α,α',α''-N-hexakis(triethylammoniummethylene chloride)-melamine as amulti-site phase-transfer catalyst in water was developed. By this eco-friendly and highly atom-economic method, a variety of 1,2-azidoalcohols was obtained in high yields with excellent regioselectivity and in short reaction times. Application of this six-site PTC in the ring opening of epoxides by cyanide, acetate and chloride anions was also studied. The catalyst can be recovered after completion of the reaction and can be recycled without affecting the catalytic property.
- Kiasat, Ali Reza,Mirzajani, Roya,Shalbaf, Haji,Tabatabaei, Tahereh,Fallah-Mehrjardi, Mehdi
-
experimental part
p. 594 - 599
(2010/07/02)
-
- Biocatalytic cascade for the synthesis of enantiopure β-azidoalcohols and β-hydroxynitriles
-
A three-step, two-enzyme, one-pot reaction sequence starting from prochiral a-chloroketones leading to enantiopure (3- azidoalcohols and (3-hydroxynitriles is described. Asymmetric bioreduction of a-chloroketones by hydrogen transfer catalysed by an alcohol dehydrogenase (ADH) established the stereogenic centre in the first step to furnish enantiopure chlorohydrin intermediates. Subsequent biocatalysed ring closure to the epoxide and nucleophilic ring opening with azide, N3-, or cyanide, CN-, both catalysed by a nonselective halohydrin dehalogenase (Hhe) proceeded with full retention of configuration to give enantiopure (-azidoalcohols and (3-hydroxynitriles, respectively. Both enantiomers of various optically pure (-azidoalcohols and (-hydroxynitriles were synthesised.
- Schrittwieser, Joerg H.,Lavandera, Ivan,Seisser, Birgit,Mautner, Barbara,Kroutil, Wolfgang
-
experimental part
p. 2293 - 2298
(2009/08/17)
-
- Hot water-promoted ring-opening of epoxides and aziridines by water and other nucleopliles
-
Effective hydrolysis of epoxides and aziridines was conducted by heating them in water at 60 or 100 °C. Other types of nucleophile such as amines, sodium azide, and thiophenol could also efficiently open epoxides and aziridines in hot water. It was proposed that hot water acted as a modest acid catalyst, reactant, and solvent in the hydrolysis reactions.
- Wang, Zhi,Cui, Yong-Tao,Xu, Zhao-Bing,Qu, Jin
-
p. 2270 - 2274
(2008/09/19)
-
- Gallium trichloride - Promoted highly regioselective ring opening of epoxides with NH4SCN and NaN3 in water
-
β-Hydroxy thiocyanates and β-azidoalchols were obtained in excellent yields via GaCl3-promoted highly regioselective ring opening of epoxides with ammonium thiocyanate or sodium azide in water. The present method is very rapid and equally compatible for b
- Chen, Xian,Wu, Huayue,Xu, Rong,Liu, Miaochang,Ding, Jinchang,Su, Weike
-
p. 1855 - 1865
(2008/09/21)
-
- Poly(ethylene glycol) grafted onto dowex resin: An efficient, recyclable, and mild polymer-supported phase transfer catalyst for the regioselective azidolysis of epoxides in water
-
(Chemical Equation Presented) In this study, an efficient method was designed to graft poly(ethylene glycol) effectively onto commercial Dowex resin. The catalytic efficiency of the copolymer obtained as a new solid-liquid phase transfer catalyst was stud
- Kiasat, Ali Reza,Badri, Rashid,Zargar, Behrouz,Sayyahi, Soheil
-
experimental part
p. 8382 - 8385
(2009/04/11)
-
- One-pot sequential synthesis of β-hydroxy-1,4-disubstituted-1,2,3- triazoles from in-situ generated β-azido alcohol by click chemistry
-
β-Hydroxy 1,2,3-triazoles from in situ generated 1,2-azidols were synthesized employing two sequential click reactions in very high yields with high regioselectivity using Cu(OAc)2·H2O as a catalyst in water at ambient temperature. Copyright Taylor & Fran
- Reddy, K. Rajender,Maheswari, C. Uma,Rajgopal,Kantam, M. Lakshmi
-
p. 2158 - 2167
(2008/09/21)
-
- Catalyst-free highly regio- and stereoselective ring opening of epoxides and aziridines with sodium azide using poly(ethylene glycol) as an efficient reaction medium
-
Ring opening of epoxides and aziridines has readily been carried out at room temperature using poly(ethylene glycol) (PEG-400) as the efficient reaction medium to form the corresponding 2-azido alcohols and 2-azido amines, respectively, in excellent yield
- Das, Biswanath,Reddy, Vtukuri Saidi,Tehseen, Fouzia,Krishnaiah, Maddeboina
-
p. 666 - 668
(2008/01/08)
-
- Efficient regioselective opening of epoxides by nucleophiles in water under simultaneous ultrasound/microwave irradiation
-
Epoxide cleavage by nucleophiles in aqueous media may suffer from competition by water itself, yielding the diol as byproduct. However, when the reaction was carried out under high-intensity ultrasound or microwaves, attack by the nucleophile was strongly promoted and water no longer reacted. Best results were achieved under simultaneous ultrasound/microwave irradiation: a series of mono-, di- and trisubstituted oxiranes reacted rapidly with sodium azide or 1-(3-chlorophenyl)piperazine, usually leading to the corresponding more substituted alcohols in acceptable to high yields. This catalyst-free, greener protocol achieves a much faster cleavage of epoxides with a high regioselectivity. Georg Thieme Verlag Stuttgart.
- Palmisano, Giovanni,Tagliapietra, Silvia,Barge, Alessandro,Binello, Arianna,Boffa, Luisa,Cravotto, Giancarlo
-
p. 2041 - 2044
(2008/02/09)
-
- Efficient regio- and stereo-selective cleavage of aziridines and epoxides using an ionic liquid as reagent and reaction medium
-
Ionic liquids, containing a variety of functionalities such as halo, azido, and thiocyano, efficiently cleave aziridines and epoxides to the corresponding products in high yields. The cleavages are regio- and stereo-selective. The reactions are complete i
- Ranu, Brindaban C.,Adak, Laksmikanta,Banerjee, Subhash
-
p. 366 - 371
(2008/03/13)
-
- Ionic liquids/H2O systems for the reaction of epoxides with NaN3: A new protocol for the synthesis of 2-azidoalcohols
-
Oxiranes undergo ring opening rapidly with sodium azide in a [bmim]BF 4/H2O or [bmim]PF6/H2O (2:1) solvent system, under mild and neutral reaction conditions to afford the corresponding 2-azidoalcohols in high t
- Yadav,Reddy,Jyothirmai,Murty
-
p. 6559 - 6562
(2007/10/03)
-
- Catalytic activation of silylated nucleophiles using tBu-P4 as a base
-
Trialkylsilyl groups play an important role as effective protecting groups in organic synthesis. Various O, N, and C nucleophilic sites can be protected by trialkylsilyl groups to control the selectivity of reactions. The nucleophilic attack of a fluoride anion on a silyl group is recognized as one of the most useful methods for desilylation. The activation of the nucleophile-silicon bond is important not only for desilylation but also for the generation of a reactive nucleophilic anion to achieve a new bond formation. The phosphazene bases developed by Schwesinger are known to be strong non-metallic organic bases. Among them, the tBu-P4 base has been used for various selective deprotonative transformations, although the ability of tBu-P4 base to activate silylated nucleophiles has not yet been shown. A novel catalytic activation of various O, N, and C nucleophile-silicon bonds using tBu-P4 base was investigated to perform nucleophilic reactions with various electrophiles. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Ueno, Masahiro,Hori, Chieko,Suzawa, Koichi,Ebisawa, Masashi,Kondo, Yoshinori
-
p. 1965 - 1968
(2007/10/03)
-
- Highly regioselective ring opening of epoxides using NaN3: A short and efficient synthesis of (-)-cytoxazone
-
A convenient and efficient synthesis of 1,2-azido alcohols has been achieved by regioselective ring opening of epoxides using NaN3 and 4 ? molecular sieves in acetonitrile. The utility of this method has been demonstrated by achieving a short synthesis of (-)-cytoxazone in 48% overall yield.
- Boruwa, Joshodeep,Borah, Jagat C.,Kalita, Biswajit,Barua, Nabin C.
-
p. 7355 - 7358
(2007/10/03)
-
- Asymmetric Schmidt reaction of hydroxyalkyl azides with ketones
-
An asymmetric equivalent of the Schmidt reaction permits stereocontrol in ring expansions of symmetrical cyclohexanones. The procedure involves the reaction of chiral 1,2- and 1,3-hydroxyalkyl azides with ketones under acid catalysis; the initial reaction affords an iminium ether that can be subsequently opened with base. A systematic study of this reaction is reported, in which ketone substrates, chiral hydroxyalkyl azides, and reaction conditions are varied. Selectivities as high as ca. 98:2 are possible for the synthesis of substituted caprolactams, with up to 1,7-stereoselection involved in the overall process. The fact that either possible migrating carbon is electronically identical provides an unusual opportunity to study a ring-expansion reaction controlled entirely by stereoelectronic factors. The mechanism of the reaction and the source of its stereoselectivity are also discussed.
- Sahasrabudhe, Kiran,Gracias, Vijaya,Furness, Kelly,Smith, Brenton T.,Katz, Christopher E.,Reddy, D. Srinivasa,Aube, Jeffrey
-
p. 7914 - 7922
(2007/10/03)
-
- Regioselective azidolysis of epoxides catalyzed with LiBF4
-
Efficient and regioselective conversion of epoxiodes to vicinal azidoalcohols with sodium azide in wet t-butanol and in the presence of catalytic amount of lithium tetrafluoroborate, LiBF4 in excellent yields under mild reaction conditions is d
- Kazemi,Kiasat,Ebrahimi
-
p. 999 - 1004
(2007/10/03)
-
- Do aziridines require Lewis acids for cleavage with ionic nucleophiles?
-
A variety of activated aziridines were cleaved by sodium azide and sodium cyanide in aqueous acetonitrile at reflux, in the absence of any Lewis acid, to provide ring-opened products in quantitative yields. However, the reaction was sluggish in the ring o
- Bisai, Alakesh,Pandey, Ghanshyam,Pandey, Manoj K.,Singh, Vinod K.
-
p. 5839 - 5841
(2007/10/03)
-
- High yield regioselective ring opening of epoxides using samarium chloride hexahydrate
-
Epoxides were converted to the corresponding β-azidohydrins and β-iodohydrins using SmCl3·6H2O/NaN3 in DMF and SmCl3·6H2/NaI in acetonitrile respectively. The reactions were highly regio-selective, ef
- Bhaumik, Kankan,Mali, Umesh W.,Akamanchi
-
p. 1603 - 1610
(2007/10/03)
-
- An Epoxide Ring-Opening Reaction via Hypervalent Silicate Intermediate: Synthesis of Statine
-
The azide- and cyanide-opening reaction of epoxide with TBAF and TMSN 3 in THF or TBAF and TMSCN in MeCN occurred regioselectively to afford β-hydroxy azides and cyanides in good yield. These hypervalent silicates have been shown to be highly effective as nucleophilic azide and cyanide donors under mild conditions. This methodology has been applied to the preparation of statine.
- Konno, Hiroyuki,Toshiro, Emi,Hinoda, Naoyuki
-
p. 2161 - 2164
(2007/10/03)
-
- Silica gel promoted highly regioselective ring opening of epoxides using NaN3 under solvent free conditions
-
A convenient and efficient synthesis of vicinal azidohydrin has been achieved by ring opening of epoxides using SiO2/NaN3 under solvent free conditions. The reaction is highly regioselective and afforded the corresponding products in
- Kiasat, Ali Reza,Kazemi, Foad
-
p. 2387 - 2392
(2007/10/03)
-
- Micellar media for the efficient ring opening of epoxides with CN-, N3-, NO3-, NO2-, SCN-, Cl- and Br- catalyzed with Ce(OTf)4
-
Micellar media are introduced for the efficient ring opening of epoxides with sodium salts of nucleophiles such as CN, N3-, NO3-, NO2, SCN, Br and Cl-, catalyzed with Ce(OTf)4. This method is an efficient procedure for the synthesis of different β-substituted alcohols under mild reaction conditions. The reaction with SCN- is an easy procedure for the high yielding preparation of epoxy sulfides.
- Iranpoor, Nasser,Firouzabadi, Habib,Shekarize, Marzieh
-
p. 724 - 727
(2007/10/03)
-