93914-54-6Relevant articles and documents
Hafnium trifluoromethanesulfonate catalyzed silyl ether protecting group removing method
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Paragraph 0009; 0013; 0014, (2019/01/21)
The invention provides a hafnium trifluoromethanesulfonate catalyzed silyl ether protecting group removing method. Various silyl ether protecting groups of nearly 50 kinds of substrates can be efficiently removed in 0.5-16 hours at room temperature by taking 0.02mol%-0.3mol% hafnium trifluoromethanesulfonate as a catalyst, a silyl ether protected hydroxyl compound as a substrate and conventional AR methanol as a solvent. 42 kinds of silyl ether protecting group removing products can be obtained at high yield by performing conventional slica column chromatography purification on a crude product. By regulating the use amount of the catalyst, the Hf(OTf)4 catalyst can realize regioselective removal of 1-degree, 2-degree and 3-degree alkyl TBS and aryl TBS protective groups. Moreover, in a proper equivalent scope, the Hf(OTf)4 catalyst can also realize 1) chemoselective removal of different kinds of silica-based protective groups; and 2) chemoselective removal of 1-degree TBS protective groups under the condition of not affecting a majority of common hydroxyl protective groups.
H3PW12O40at the[bmim][FeCl4]: A green catalytic system for alkoxymethylation of alcohols and their one-pot interconversion to acetates and TMS-ethers
Mohammadpoor-Baltork,Moghadam,Tangestaninejad,Mirkhani,Khosropour,Mirjafari
experimental part, p. 513 - 524 (2012/06/16)
12-Tungstophosphoric acid immobilized on [bmim][FeCl4] was found to be an efficient catalyst for chemoselective methoxymethylation and ethxoymethylation of alcohols and also one-pot conversion of MOM- or EOM-ethers to their corresponding acetates and TMS-ethers under thermal conditions and microwave irradiation. These procedures were simple, rapid and the corresponding products were obtained in high yields. The catalyst exhibited remarkable reactivity and was reusable.
Chemoselective control of hydrogenation among aromatic carbonyl and benzyl alcohol derivatives using Pd/C(en) catalyst
Hattori, Kazuyuki,Sajiki, Hironao,Hirota, Kosaku
, p. 4817 - 4824 (2007/10/03)
The hydrogenolysis of aromatic ketones and aldehydes quite smoothly give the corresponding methylene compounds via the formation of the intermediary benzyl alcohols in the presence of Pd/C as a catalyst. Therefore, it is extremely difficult to isolate the intermediary benzyl alcohol selectively. This paper describes a mild and chemoselective hydrogenation method of an aromatic carbonyl compound to benzyl alcohol using the 10% Pd/C(en) catalyst and its application to the chemoselective deacetoxylation reaction at the benzylic position in the presence of the benzyl alcohol functionality within the molecule.