825-94-5Relevant articles and documents
Asymmetric Synthesis of Silicon-Stereogenic Silanes by Copper-Catalyzed Desymmetrizing Protoboration of Vinylsilanes
Li, Yanfei,Wang, Ying,Xiong, Tao,Zhang, Ge,Zhang, Qian
supporting information, p. 11927 - 11931 (2020/05/22)
The catalytic asymmetric creation of silanes with silicon stereocenters is a long-sought but underdeveloped topic, and only a handful of examples have been reported. Moreover, the construction of chiral silanes containing (more than) two stereocenters is a more arduous task and remains unexploited. We herein report an unprecedented copper-catalyzed desymmetrizing protoboration of divinyl-substituted silanes with bis(pinacolato)diboron (B2pin2). This method enables the facile preparation of an array of enantiomerically enriched boronate-substituted organosilanes bearing contiguous silicon and carbon stereocenters with exclusive regioselectivity and generally excellent diastereo- and enantioselectivity.
A kind of preparation method of the midbody of entecavir, and intermediate
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Paragraph 0386 - 0391; 0399; 0408, (2017/08/02)
The invention discloses Entecavir intermediates and a preparation method thereof. The preparation method of an Entecavir intermediate represented by a formula IV or IV' shown in descriptions comprises the following step of enabling a compound V to be subjected to amino protecting group and hydroxyl protecting group removal reaction in the presence of protonic acid in a solvent. The preparation method disclosed by the invention has the advantages that raw materials are cheap and are easily obtained, reaction conditions are mild, side reactions are few, the yield is high, the pollution to the environment is little, and the intermediates are easily purified and separated, so that the preparation method is applicable to industrial production.
Entecavir intermediate and its preparation method
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Paragraph 0380-0383; 0393; 0394; 0401, (2017/12/28)
The invention discloses an entecavir intermediate and a preparation method thereof. A provided preparation method for an entecavir intermediate compound 10 comprises the following steps: performing reducing reaction on an ester compound 11 in an organic solvent under the effect of a reducing agent, so as to obtain the compound 10. A provided preparation method for an entecavir intermediate compound 11 comprises the following steps: reacting a compound 12 with a hydroxyl protection reagent in an organic solvent in the presence of an acid to add a hydroxyl protection group, so as to obtain the compound 11. The preparation methods are cheap and easily available in raw materials, mild in reaction conditions, relatively high in product yield, good in atom economy, friendly to environment, and suitable for industrialized production.
Entecavir intermediate and its preparation method
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Paragraph 0377-0382; 0391; 0392; 0401, (2017/12/28)
The invention discloses an entecavir intermediate and a preparation method thereof. A provided preparation method for an entecavir intermediate compound 8 comprises the following steps: performing hydroxyl protection group removal reaction on a compound 9 in a solvent under an acidic condition, so as to obtain the compound 8. A provided preparation method for an entecavir intermediate compound 9 comprises the following steps: performing hydroxyl protection group adding reaction on a compound 10 in an aprotic organic solvent under an alkali condition, so as to obtain the compound 9. The preparation methods are cheap and easily available in raw materials, mild in reaction conditions, relatively high in product yield, good in atom economy, friendly to environment, and suitable for industrialized production.
Synthesis and characterization of new aromatic-group substituted silanes bearing tris (trimethylsilyl)methyl bulky groups
Tarassoli, Abbas,Asadi, Ashrafolmolouk
experimental part, p. 1463 - 1468 (2010/09/09)
Reaction of the Grignard reagent, p-ClC6H4MgCl, with SiCl4 in toluene gave (p-ClC6H4) 2SiCl2, which was treated with KHF2 to give (p-ClC6H4)2SiF2 (1). Reaction of the latter with [(Me3Si)3C]Li in THF leads to the preparation of [(Me3Si)3C](p-ClC6H4) 2SiF (2). Treatment of (2) with LiAlH4 gave [(Me 3Si)3C](p-ClC6H4)2SiH (3) and [(Me3Si)3C](p-ClC6H4)(C 6H5)SiH (4). [(Me3Si)3C](p-ClC 6H4)SiCl2 (5) was also prepared from the reaction of (p-ClC6H4)SiCl3 with [(Me 3Si)3C]Li in a similar manner. The new highly sterically hindered organosilicon reagents (2) to (5) have been fully characterized by IR, 1H and 13C NMR, and mass spectrometry as well as elemental analysis. Copyright Taylor & Francis Group, LLC.