IMMEDIATE AND HIGH YIELDING SOLVENT-FREE OXIDATION OF SILYL AND PYRANYL ETHERS TO THEIR CORRESPOUNDING CARBONYL COMPOUNDS WITH ZINC DICHROMATE TRIHYDRATE (ZnCr2O7·3H2O)
摘要:
Zinc dichromate trihydrate (ZnCr2O7.3H(2)O) is an efficient reagent for the immediate deprotection of aromatic and aliphatic silyl and pyranyl ethers into their corresponding carbonyl compounds in high yields at room temperature under solvent-free conditions.
HF–Pyridine: A Versatile Promoter for Monoacylation/Sulfonylation of Phenolic Diols and for Direct Conversion of <i>t</i>-Butyldimethylsilyl Ethers to the Corresponding Acetates
Monoacylation and trifluoromethanesulfonylation of phenolic diols were achieved by the aid of HF–pyridine, whereas diacylation occurred with pyridine alone. Furthermore, HF–pyridine was found to promote the direct conversion of t-butyldimethylsilyl ethers to the corresponding acetates.
Deprotection of Acetals and Silyl Ethers Using a Polymer-Supported π-Acid Catalyst: Chemoselectivity and Polymer Effect
作者:Nobuyuki Tanaka、Yukio Masaki
DOI:10.1055/s-1999-3000
日期:1999.12
A polymeric dicyanoketene acetal (DCKA), prepared from a styrene monomer bearing dicyanoketene acetal functionality, was found to be an effective and recyclable catalyst in the chemoselective deprotection of acetals and silyl ethers. A remarkable acceleration accountable for the polymer effect was observed.
metal-free, and homogeneous method for the selectiveaerobic photooxidation of alcohols and photooxidative-desilylation of tert-butyldimethylsilyl ethers (TBDMS) in the presence of tetrabutylammonium tribromide (TBATB) under irradiation of visiblelight was reported. The light source: blue (460 nm) and violet (400 nm) LED, can control selectiveoxidation to aldehyde or carboxylic acid.
Novel Polymer Effect in Cleavage Reactions of Acetals and Silyl Ethers in Aqueous Media Catalyzed by a Polymer-Supported Dicyanoketene Acetal
作者:Yukio Masaki、Tomoyasu Yamada、Nobuyuki Tanaka
DOI:10.1055/s-2001-16073
日期:——
Deprotecting reactions of acetals including acetonides, ethylene acetals, and THP ethers of alcohols, an aldehyde, and ketones, and silyl ethers of primary and secondary alcohols were investigated using dicyanoketeneacetals (DCKA) and a polymer-supported DCKA as a π-acid promoter in aqueous acetonitrile and a single aqueous medium. In all reactions catalytic activity of the polymer-supported DCKA