- Melamine trisulfonic acid (MTSA): A new efficient catalyst for the chemoselective methoxymethylation of alcohols
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Melamine trisulfonic acid, which is easily prepared by the reaction of melamine with neat chlorosulfonic acid, is able to efficiently catalyze the chemoselective methoxymethylation of alcohols with dimethoxymethane (DMM). All reactions were performed unde
- Shirini, Farhad,Zolfigol, Mohammad Ali,Albadi, Jalal
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- BiCl3-Facilitated removal of methoxymethyl-ether/ester derivatives and DFT study of -O-C-O- bond cleavage
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A simple method for the cleavage of methoxymethyl (MOM)-ether and ester derivatives using bismuth trichloride (BiCl3) is described. The alkyl, alkenyl, alkynyl, benzyl and anthracene MOM ether derivatives, as well as MOM esters of both aliphatic and aromatic carboxylic acids, were deprotected in good yields. To better understand the molecular roles of BiCl3and water for MOM cleavage, two possible binding pathways were investigated using the density functional theory (DFT) method. The theoretical results indicate the differential initial binding site preferences of phenolic and alcoholic MOM substrates to the Bi atom and suggest that water plays a key role in facilitating the cleavage of the MOM group.
- Pacherille, Angela,Tuga, Beza,Hallooman, Dhanashree,Dos Reis, Isaac,Vermette, Mélodie,Issack, Bilkiss B.,Rhyman, Lydia,Ramasami, Ponnadurai,Sunasee, Rajesh
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supporting information
p. 7109 - 7116
(2021/05/03)
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- A chloromethyl methyl ether and its armor oxygen methyl protection method for the synthesis of the compounds of
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The invention provides chloromethyl methyl ether and a synthesis method of a compound protected by methoxymethyl thereof. The chloromethyl methyl ether (MOMCl) is a common protective reagent in organic synthesis. Commonly used synthesis methods are tedious in operation and long in reaction time. The synthesis method provided by the invention comprises: with trifluoromethane sulfonic acid or perchloric acid as a catalyst, reacting acyl chloride with dimethoxymethane to synthesize the chloromethyl methyl ether. The chloromethyl methyl ether produced in situ can directly act with a hydroxyl compound and organic alkali dissolved in an organic solvent to generate a product with hydroxyl protected by MOM. The method has the advantages of high reaction speed and simple reaction operation. Therefore, the method can be applicable to the production and application of a continuous flow reactor.
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Paragraph 0053; 0054; 0055; 0056
(2016/10/10)
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- Synthesis of Ethers via Reaction of Carbanions and Monoperoxyacetals
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Although transfer of electrophilic alkoxyl ("RO+") from organic peroxides to organometallics offers a complement to traditional methods for etherification, application has been limited by constraints associated with peroxide reactivity and stability. We now demonstrate that readily prepared tetrahydropyranyl monoperoxyacetals react with sp3 and sp2 organolithium and organomagnesium reagents to furnish moderate to high yields of ethers. The method is successfully applied to the synthesis of alkyl, alkenyl, aryl, heteroaryl, and cyclopropyl ethers, mixed O,O-acetals, and S,S,O-orthoesters. In contrast to reactions of dialkyl and alkyl/silyl peroxides, the displacements of monoperoxyacetals provide no evidence for alkoxy radical intermediates. At the same time, the high yields observed for transfer of primary, secondary, or tertiary alkoxides, the latter involving attack on neopentyl oxygen, are inconsistent with an SN2 mechanism. Theoretical studies suggest a mechanism involving Lewis acid promoted insertion of organometallics into the O-O bond.
- Kyasa, ShivaKumar,Meier, Rebecca N.,Pardini, Ruth A.,Truttmann, Tristan K.,Kuwata, Keith T.,Dussault, Patrick H.
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p. 12100 - 12114
(2016/01/09)
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- A mild and efficient method for the methoxymethylation and acetylation of alcohols promoted by benzyltriphenylphosphonium tribromide
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A mild and efficient method for the conversion of alcohols to their corresponding methoxymethyl ethers and acetates using benzyltriphenylphosphonium tribromide (BTPTB) as catalyst is described. All reactions were performed under completely heterogeneous reaction conditions in good to high yields.
- Shirini, Farhad,Imanzadeh, Gholam Hossein,Mousazadeh, Seyyed Ali Reza,Mohammadpoor-Baltork, Iraj,Abedin, Masoumeh
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experimental part
p. 1187 - 1190
(2011/10/05)
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- Scandium trifluoromethanesulfonate as a recyclable catalyst for efficient methoxymethylation of alcohols
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Scandium triflate [Sc(OTf)3] has been found to be a recyclable catalyst for mild highly efficient methoxymethylation of a variety of alcohols using formaldehyde dimethyl acetal (FDMA).
- Karimi, Babak,Ma'mani, Leyla
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p. 6051 - 6053
(2007/10/03)
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- A One-Step Conversion of p-Methoxybenzyl Ethers into Methoxymethyl Ethers by the Action of Dimethoxymethane in the Presence of Tin(II) Bromide and Bromomethyl Methyl Ether
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The combined use of dimethoxymethane with catalytic amounts of tin(II) bromide and bromomethyl methyl ether cleaves p-methoxybenzyl ethers to give methoxymethyl ethers in good yields.The chemoselective conversion of p-methoxybenzyl ethers in the presence of the benzyl ether function into methoxymethyl ethers has also occurred successfully.
- Oriyama, Takeshi,Kimura, Mikio,Koga, Gen
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p. 885 - 887
(2007/10/02)
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- Dimethylboron Bromide and Diphenylboron Bromide: Cleavage of Acetals and Ketals
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The cleavage of various acetal and ketal derivatives by the use of dialkyl- and diarylboron halides is described.Acetals and ketals readily react with dimethylboron bromide or diphenylboron bromide at -78 deg C to give the corresponding carbonyl compounds in excellent yield.Under similar reaction conditions MEM, MOM, and MTM ethers are smoothly converted to alcohols.Acetonides are also cleaved with dimethylboron bromide while THP and THF ethers and methyl glycosides react at room temperature.Mechanistic considerations of the cleavage reactions are presented.The chemoselective virtues of dimethylboron bromide are summarized.
- Guindon, Yvan,Yoakim, Christiane,Morton, Howard E.
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p. 3912 - 3920
(2007/10/02)
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