Silica chromate as an oxidising agent for the chemoselective oxidation of alcohols and the oxidative deprotection of trimethylsilyl ethers
摘要:
Silica chromate easily converts primary and secondary alcohols to corresponding carbonyl compounds in the presence of wet SiO2 both in dichloromethane and under solvent-free conditions at room temperature with good to excellent yields. Primary and secondary trimethylsilyl ethers were converted into the corresponding carbonyl compounds or alcohols by using silica chromate and wet SiO2 in dichloromethane at room temperature with good to excellent yields.
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
1,3-Dichloro-5,5-Dimethylhydantoin (DCH) and Trichloromelamine (TCM) as Efficient Catalysts for the Chemoselective Trimethylsilylation of Hydroxyl Group with 1,1,1,3,3,3-Hexamethyldisilazane (HMDS) Under Mild Conditions
作者:Arash Ghorbani-Choghamarani、Kamal Amani、Mohammad Ali Zolfigol、Maryam Hajjami、Roia Ayazi-Nasrabadi
DOI:10.1002/jccs.200900037
日期:2009.4
A highly convenient method for the trimethylsilylation of alcohols and phenols via treatment by hexamethyldisilazane in the presence of 1,3–dichloro‐5,5–dimethylhydantoin (DCH) and/or trichloromelamine (TCM) as a catalyst has been developed. A wide variety of hydroxylgroups were selectively protected in CH2Cl2/CH3CN undermildconditions.
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.
{[[K.18-Crown-6]Br3}n: A tribromide catalyst for the catalytic protection of amines and alcohols
作者:Gholamabbas Chehardoli、Mohammad Ali Zolfigol、Fateme Derakhshanpanah
DOI:10.1016/s1872-2067(12)60644-5
日期:2013.9
[K.18-Crown-6]Br3}n, a unique tribromide-type catalyst, was utilized for the N-boc protection of amines and trimethylsilylation (TMS) and tetrahydropyranylation (THP) of alcohols. The method is general for the preparation of N-boc derivatives of aliphatic (acyclic and cyclic) and aromatic, and primary and secondary amines and also various TMS-ethers and THP-ethers. The simple separation of the catalyst
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