- Anionic Fries rearrangement of aryl carbonates. A facile route to ortho-hydroxy esters
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Aryl carbonates react with LDA or LiTMP to produce ortho-hydroxy esters.
- Ananin, Aleksei V.,Kraus, George A.
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supporting information
(2020/10/13)
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- MgBr 2 · OEt 2: A Lewis Acid Catalyst for the O - And N -Boc Protection of Phenols and Amines
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MgBr2 · OEt2 efficiently catalyzes the O- and N-tert-butoxycarbonylation of functionalized phenols and amines. The presented procedure is operationally simple and done under solvent-free conditions. GRAPHICAL ABSTRACT.
- Schechter, Aaron,Goldrich, David,Chapman, Jessica R.,Uberheide, Beatrix M.,Lim, Daniel
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supporting information
p. 653 - 660
(2015/10/29)
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- A new, efficient, and catalyst-free microwave-assisted approach for formation of O-tert-butoxy carbonates
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A new simple, efficient, greener, and catalyst-free chemoselective protocol for the O-tert-butoxycarbonylation of various structurally diverse hydroxy compounds was carried out with (Boc)2O under microwave radiation. The corresponding O-tertbutoxy carbonates were obtained in good to excellent yields in a short reaction time without any side reactions.
- K'tir, Hacene,Amira, Aicha,Berredjem, Malika,Aouf, Nour-Eddine
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supporting information
p. 851 - 853
(2014/06/23)
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- Mixed metal MgO-ZrO2 nanoparticle-catalyzed O-tert-Boc protection of alcohols and phenols under solvent-free conditions
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An environmentally benign method for O-tert-Boc protection of alcohols and phenols catalyzed by MgO-ZrO2 nanoparticles under solvent-free conditions is described. A variety of phenols, alcohols (aliphatic and aromatic) were converted to corresponding O-tert-Boc products in good to excellent yield (50-95%). The present protocol is expedient, simple, and efficient under solvent-free conditions. The MgO-ZrO2 Nps are easily prepared from inexpensive precursors, and are reusable, recyclable and chemoselective. Copyright 2012 John Wiley & Sons, Ltd. Copyright
- Gawande, Manoj B.,Shelke, Sharad N.,Branco, Paula S.,Rathi, Anuj,Pandey, Rajesh K.
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experimental part
p. 395 - 400
(2012/09/25)
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- Nickel catalyzed cross-coupling of aryl C-O based electrophiles with aryl neopentylglycolboronates
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The efficiency of mesylates, sulfamates, esters, carbonates, carbamates, and methyl ethers as C-O-based electrophiles attached to the 1- or 2-position of naphthalene and to activated and nonactivated phenyl substrates was compared for the first time in Ni-catalyzed cross-coupling with phenyl neopentylglycolboronates containing electron-rich and electron-deficient substituents in their para-position. These experiments were performed in the presence of four different Ni(II)- and Ni(0)-based catalysts. Ni(II)-based catalysts mediate the cross-coupling of most 2-naphthyl C-O electrophiles with both arylboronic acids and with neopentylglycolboronates when K 3PO4 is used as base. The same catalysts are not efficient when CsF is used as base. However, Ni(0)-based catalysts exhibit selective efficiency, and when reactive, their efficiency is higher than that of Ni(II)-based catalysts in the presence of both K3PO4 and CsF. These results provide both reaction conditions for the cross-coupling, and for the elaboration of orthogonal cross-coupling methodologies of various C-O based electrophiles with aryl neopentylglycolboronates. With the exception of mesylates and sulfamates the efficiency of all other 2-naphthyl C-O electrophiles was lower in cross-coupling with aryl neopentylglycolboronates than with arylboronic acids
- Leowanawat, Pawaret,Zhang, Na,Percec, Virgil
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experimental part
p. 1018 - 1025
(2012/03/22)
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- An eco-sustainable erbium(iii)-catalyzed method for formation/cleavage of O-tert-butoxy carbonates
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A new simple and effective method for the formation/cleavage of O-tert-butoxy carbonates of alcohols and phenols is proposed. Mesoporous silica-supported Er(iii) (ErIII-MCM-41) was used as an efficient and reusable solid catalyst in the solvent-free ultrasound-assisted synthesis of Boc-carbonate derivatives of a wide range of alcohols and phenols. The fast, selective deprotection of Boc-derivatives is achieved with a very low amount of Er(OTf)3 in ethanol under microwave irradiation. Therefore, the entire protection/de-protection process is very attractive, from the point of view of sustainability.
- Procopio, Antonio,Cravotto, Giancarlo,Oliverio, Manuela,Costanzo, Paola,Nardi, Monica,Paonessa, Rosina
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experimental part
p. 436 - 443
(2011/04/17)
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- An eco-sustainable erbium(III) triflate catalyzed formation and cleavage of tert -butyl ethers
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An eco-compatible method, which permits the formation or cleavage of tert-butyl ethers of alcohols and phenols, is proposed. The protection step is performed in solvent-free conditions at room temperature using catalytic amount of Er(OTf)3. The catalyst is easily- recovered from the aqueous phase and reused several times without significant loss of activity. The deprotection step developed is also highly eco-friendly since the tert-butyl group is removed very quickly from alcohols and phenols in methanol using MW irradiation-. Georg Thieme Verlag Stuttgart · New York.
- Procopio, Antonio,Costanzo, Paola,Curini, Massimo,Nardi, Monica,Oliverio, Manuela,Paonessa, Rosina
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supporting information; experimental part
p. 73 - 78
(2011/03/19)
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- Chemoselective O-tert-butoxycarbonylation of phenols using 6,7-dimethoxyisoquinoline as a novel organocatalyst
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The chemoselective O-tert-butoxycarbonylation of phenols using low levels (5-0.1 mol %) of 6,7-dimeth-oxyisoquinoline as a reusable organocatalyst is described.
- Saito, Yukako,Yoshimura, Yuichi,Takahata, Hiroki
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experimental part
p. 6915 - 6917
(2011/03/18)
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- Facile tert-butoxycarbonylation of alcohols, phenols, and amines using BiCl3 as a mild and efficient catalyst
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Facile tert-butoxycarbonylation of alcohols, phenols, and amines is described by treatment of alcohols, phenols, and amines with di-tert-butyl dicarbonate in the presence of a catalytic amount of bismuth(III) chloride, a mild and efficient catalyst, at room temperature in excellent yields. Copyright Taylor & Francis Group, LLC.
- Suryakiran,Prabhakar,Venkateswarlu
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p. 177 - 185
(2008/03/17)
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- Organocatalytic methods for chemoselective O-tert-butoxycarbonylation of phenols and their regeneration from the O-t-Boc derivatives
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(Chemical Equation Presented) Carbon tetrabromide (CBr4) catalyzes O-tert-butoxycarbonylation of functionalized phenols without any side reactions (bromination, addition of CBr3 to a double bond, and formation of symmetrical diaryl carbonates, cyclic carbonates, or carbonic-carbonic anhydrides). The parent phenols are regenerated from the O-t-Boc derivatives by the catalyst system CBr4-PPh3 without affecting other protecting groups (aryl alkyl ether, alkyl ester, and thioacetal) or competitive side reaction such as bromination, nitrene (from NO2) and α,α-dibromoolefine (with CHO/COMe) formation, and transesterification (with CO2Me/Et) taking place.
- Chankeshwara, Sunay V.,Chebolu, Rajesh,Chakraborti, Asit K.
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supporting information; scheme or table
p. 8615 - 8618
(2009/04/11)
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- Triphenylphosphine as a novel organocatalyst for chemoselective O-tert-butoxycarbonylation of phenols
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A novel organocatalytic procedure for the chemoselective O-tert-butoxycarbonylation of phenols under neutral and neat conditions is described. Georg Thieme Verlag Stuttgart.
- Chebolu, Rajesh,Chankeshwara, Sunay V.,Chakraborti, Asit K.
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p. 1448 - 1454
(2008/12/21)
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- The first simple method of protection of hydroxy compounds as their O-Boc derivatives under Lewis acid catalysis
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The first Lewis acid catalyzed protection of alcohols as Boc derivatives is described. Zinc acetate is a very efficient catalyst for this transformation and the reaction can be applied to primary, secondary and aromatic alcohols, providing the first example of a generally applicable method. Georg Thieme Verlag Stuttgart.
- Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Dalpozzo, Renato,Locatelli, Manuela,Melchiorre, Paolo,Palazzi, Paolo,Sambri, Letizia
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p. 2104 - 2108
(2008/02/05)
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- A novel tert-butoxycarbonylation reagent: 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline (BBDI)
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The use of 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline (BBDI) as a tert-butoxycarbonylation reagent for acidic proton-containing substrates such as phenols, aromatic and aliphatic amines hydrochlorides, and aromatic carboxylic acids in the absence of a base is described. The reactions proceed chemoselectively in high yield under mild conditions.
- Saito, Yukako,Ouchi, Hidekazu,Takahata, Hiroki
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p. 11599 - 11607
(2007/10/03)
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- 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline: A novel and chemoselective tert-butoxycarbonylation reagent
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(formula presented) The use of 1-tert-butoxy-2-tert-butoxycarbonyl-1,2-dihydroisoquinoline (BBDI) as tert-butoxycarbonylation reagent for aromatic and aliphatic amine hydrochlorides and phenols in the absence of a base has been demonstrated. The reactions proceed chemoselectively in high yield under mild conditions.
- Ouchi, Hidekazu,Saito, Yukako,Yamamoto, Yutaka,Takahata, Hiroki
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p. 585 - 587
(2007/10/03)
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