Heterogeneous Thiocyanation of Benzylic Alcohols and Silyl and THP Ethers, and Deprotection of Silyl and THP-Ethers by [PCl3-n(SiO2)n] (Silphos)
摘要:
Silicaphosphite (silphos), [PCl3-n(SiO2)n], as a heterogeneous phosphorous compound, catalyzes the thiocyanation of benzylic alcohols and silyl and THP ethers in the presence of I2 and NH4SCN in refluxing CH3CN. The produced silphos oxide byproduct can be easily separated by a simple filtration. Silphos is also used for the efficient and selective deprotection of silyl and THP-ethers to their corresponding alcohols.
3° alkyl and aryl tert-butyldimethylsilyl (TBS) ethers are significantly different, ranging from 0.05 mol% to 3 mol%, regioselective deprotection of TBS could be easily implemented. Moreover, chemoselective cleavage of different silylethers or removal of TBS in the presence of most hydroxyl protecting groups was also accomplished. NMR analyses of silyl products from TBS deprotection indicated that Hf(OTf)4-catalyzed
Highly sulphated cellulose: a versatile, reusable and selective desilylating agent for deprotection of alcoholic TBDMS ethers
作者:Soma Shekar Dachavaram、Narsimha R. Penthala、Julie L. Calahan、Eric J. Munson、Peter A. Crooks
DOI:10.1039/c8ob01438h
日期:——
A mild, efficient and rapid protocol was developed for the deprotection of alcoholic TBDMS ethersusing a recyclable, eco-friendly highly sulphated cellulose sulphate acid catalyst in methanol. This acid catalyst selectively cleaves alcoholic TBDMS ethers in bis-TBDMS ethers containing both alcoholic and phenolic TBDMS ether moieties.
A mild, efficient, and selective deprotection of tert-butyldimethylsilyl (TBDMS) ethers using dicationic ionic liquid as a catalyst
作者:Arvind H. Jadhav、Hern Kim
DOI:10.1016/j.tetlet.2012.07.108
日期:2012.9
Selectivedeprotection of alkyl TBDMS ether in the presence of phenolic TBDMS etherusing dicationic ionic liquid [tetraEG(mim)2][OMs]2 as a homogeneous catalyst showed significant catalytic activity in methanol at ambient temperature to produce respective alcohol in excellent yield. The present environmentally benign catalytic system is found to be very convenient, fast, high yielding, and clean method
The chemoselective and efficient deprotection of silyl ethers using trimethylsilyl bromide
作者:Syed Tasadaque A. Shah、Patrick J. Guiry
DOI:10.1039/b803949f
日期:——
An efficient and chemoselective cleavage of silyl ethers (primary, secondary and aromatic) by using catalytic quantities of trimethylsilylbromide (TMSBr) in methanol is reported. A wide range of alkyl silyl ethers such as TBS, TIPS, and TBDPS can be chemoselectively cleaved in high yield in the presence of aryl silyl ethers. The deprotection of silyl esters was also achieved employing catalytic quantities
Preparation of Nano Silica Supported Sodium Hydrogen Sulfate: As an Efficient Catalyst for the Trimethyl, Triethyl and<i>t</i>-Butyldimethyl Silylations of Aliphatic and Aromatic Alcohols in Solution and under Solvent-free Conditions
作者:Abdolreza Abri、Somayeh Ranjdar
DOI:10.1002/jccs.201300586
日期:2014.8
Nano silicasupportedsodiumhydrogensulfate has been prepared by mixing NaHSO4 with activated Nano silicagel. We wish to report a new method for the synthesis of trimethyl (TMS), triethyl (TES) and t‐butyldimethyl silyl (TBS) ethers from benzylic, allylic, propargylic alcohols, phenols, naphtholes and some of phenolic drugs in the solution and under solvent‐free conditions.