Transdithioacetalization of acetals, ketals, oximes, enamines and tosylhydrazones catalysed by natural kaolinitic clay
作者:G. K. Jnaneshwara、N. B. Barhate、A. Sudalai、V. H. Deshpande、R. D. Wakharkar、A. S. Gajare、M. S. Shingare、R. Sukumar
DOI:10.1039/a706475f
日期:——
Natural kaolinitic clay efficiently catalyses the transdithioacetalization of acetals, ketals, oximes, enamines and tosylhydrazones with ethane-1,2-dithiol and propane-1,3-dithiol to produce the corresponding dithiolanes in high yields.
Tetrafluoroboric Acid Adsorbed on Silica Gel as a Reusable Heterogeneous Dual-Purpose Catalyst for Conversion of Aldehydes/Ketones into Acetals/Ketals and Back Again
作者:Asit Chakraborti、Dinesh Kumar、Raj Kumar
DOI:10.1055/s-2008-1042940
日期:2008.4
hydes/ketones are regenerated from the corresponding acetals/ ketals in high yields by the treatment with water-alcohol in the pres- ence of HBF4-SiO2 at room temperature for short times. Excellent selectivity was observed during inter- and intramolecular competi- tion studies involving carbonyl substrates with varying electronic and steric environments. Selective acetalformation of benzalde- hyde takes
Perchloric Acid Adsorbed on Silica Gel (HClO<sub>4</sub>-SiO<sub>2</sub>) as an Inexpensive, Extremely Efficient, and Reusable Dual Catalyst System for Acetal/Ketal Formation and Their Deprotection to Aldehydes/Ketones
作者:Asit Chakraborti、Raj Kumar、Dinesh Kumar
DOI:10.1055/s-2006-958948
日期:2007.1
Perchloric acid adsorbed on silicagel (HClO 4 -SiO 2 ) is reported as extremely efficient, inexpensive, and reusable catalyst for dual role for protection of aldehydes/ketones (with trialkyl orthoformates) as acetals/ketals and deprotection (with water-alcohol) to regenerate the carbonyl compounds in high yields at room temperature and in short times. Acetalization/ketalization of electrophilic aldehydes/ketones
Cobalt(II)-catalyzed chemoselective synthesis of acetals from aldehydes
作者:Subbarayan Velusamy、T Punniyamurthy
DOI:10.1016/j.tetlet.2004.04.126
日期:2004.6
The acetalization of aldehydes has been studied with methanol, ethanol, and 2-propanol using CoCl2 in high yields under reflux conditions. The reaction is simple, efficient, chemoselective and does not involve any other additive.
This is the first report of a simple and general method for acetalization of aldehydes via an α-chymotrypsin-induced reaction under mild conditions. A broad range of aromatic and heteroaromatic aldehydes have been acetalized under neutral conditions in good yields using a catalytic amount of chymotrypsin.