Perchloric Acid Adsorbed on Silica Gel (HClO<sub>4</sub>-SiO<sub>2</sub>) as an Extremely Efficient and Reusable Catalyst for 1,3-Dithiolane/Dithiane Formation
作者:Asit Chakraborti、Santosh Rudrawar、Ram Besra
DOI:10.1055/s-2006-942474
日期:2006.8
Perchloric acid adsorbed on silicagel (HClO 4 -SiO 2 ) has been found to be an extremely efficient and reusable catalyst for 1,3-dithiolane and 1,3-dithiane formation under solvent-free conditions at room temperature.
Copper(II) tetrafluoroborate as an extremely efficient catalyst for 1,3-dithiolane/dithiane formation from carbonyl compounds under solvent-free conditions at room temperature
作者:Ram C. Besra、Santosh Rudrawar、Asit K. Chakraborti
DOI:10.1016/j.tetlet.2005.07.059
日期:2005.9
formation from aromatic, heteroaromatic and aliphatic aldehydes and cyclic saturated ketones in 1–5 min under solvent-free conditions at room temperature. The reaction is compatible with other functionalities such as ether, ester, hydroxyl, halide, nitro and cyano groups and exhibits excellent chemoselectivity. α,β-Unsaturated aldehydes/ketones lead to selective formation of 1,3-dithiolanes instead of
Phosphorus pentoxide supported on silica gel (P2O5/SiO2) efficiently acts as a highly active and reusable catalyst for cyclic and non-cyclic S,S-acetalization of a variety of carbonyl compounds under mild, solvent-free and ambient conditions. This method offers significant advantages such as high conversion, clean work-up, short reaction times and simplicity in operation.[GRAPHICS].