eco-friendly protocol for the chemoselective protection of benzylic and primary and less hindered secondary aliphatic alcohols and phenols as trimethylsilyl ethers and different types of amines as N-tert-butylcarbamates is developed using rice husk (RiH) as the catalyst. This reagent is also able to catalyze the acetylation of alcohols, phenols, thiols and amines with acetic anhydride. Easy work-up, relatively
(PhCH<sub>2</sub>PPh<sub>3</sub>)<sup>+</sup>Br<sub>3</sub><sup>−</sup>: A Versatile Reagent for the Preparation, Deprotection, and Oxidation of Trimethylsilyl Ethers
作者:F. Shirini、G. H. Imanzadeh、A. R. Mousazadeh、I. Mohammadpoor-Baltork、A. R. Aliakbar、M. Abedini
DOI:10.1080/10426500902915440
日期:2010.2.23
Benzyltriphenylphosphonium tribromide (BTPTB), as a stable solid reagent, is easily prepared by the reaction of benzyltriphenylphosphonium bromide with Br2. This reagent can be used as an efficient catalyst for the conversion of alcohols to their corresponding trimethylsilyl ethers (TMS ethers) with hexamethyldisilazane (HMDS). Desilylation of TMS ethers is also catalyzed by BTPTB in MeOH at room temperature
A Mild and Efficient Method for Chemoselective Silylation of Alcohols Using Hexamethyldisilazane in the Presence of Silica Chloride
作者:Farhad Shirini、Mohammad Ali Zolfigol、Kamal Mohammadi
DOI:10.1080/10426500307866
日期:2003.7
Reaction of alcohols with hexamethyldisilazane in the presence of silica chloride provides efficiently the corresponding trimethylsilyl ethers. This system discriminates absolutely amines and thiols from alcohols.
at room temperature. While, under the same reaction conditions [Sn IV (TPP)Cl 2 ] is less efficient to catalyze these reactions. One important feature of this catalyst is its ability in the chemoselective silylation of primary alcohols in the presence of secondary and tertiaryalcohols and phenols. The catalyst was reused several times without loss of its catalytic activity.
Introduction of PEG-SANM nanocomposite as a new and highly efficient reagent for the promotion of the silylation of alcohols and phenols and deprotection of the silyl ethers
was prepared by a simple method and characterized using XRD, TGA, SEM, TEM, and FT-IR techniques. After preparation and characterization, this reagent was used as a highlyefficient and reusable solid acid catalyst for the chemoselective silylation of alcohols and phenols and deprotection of the obtained silyl ethers. The method offers several advantages including high to excellent yields of the products