Journal Article

Under solvent free conditions between 40-50 °C, BF3.SiO2, a mild solid acid catalyst, is applied to regio-chemo and stereoselective Claisen-Schmidt condensation. The procedure is very simple and the products are isolated with an easy workup in good to excellent yields.

A new sulfonating agent, namely bis(trimethylsilyl) sulfate, was found, which easily sulfonates benzene derivatives that contain substituents of the first type, and also thiophene. Benzene and nitrobenzene do not react with bis (trimethylsilyl) sulfate.

Bis(trimethylsilyl) sulfate-silica has been shown to be an efficient reagent system for promoting thioacetalisation of carbonyl compounds at room temperature.

It was established by IR spectroscopy and chemical analysis that bis(trimethylsilyl) sulfate reacts chemically with isolated silanol groups of silica even at room temperature, and is quantitatively chemisorbed at 373 K. Sulfidation of the silica does not occur. Chemisorption of [(CH3)3Si]2SO4 on the surface of silicon(IV) oxide is not complicated by side processes.

Le sulfate de bis (triméthylsilyle) composé aisément accessible, permet d'introduire le groupe sulfonique dans des dérivés fonctionnels tels que les éthers aromatiques, les chlorures et anhydrides d'acides aliphatiques, sans qu'il y ait de modifications notables de la fonction considerée. Dans le cas d'in chlorure d'acide alpha-chloré, on observe cependant une disulfonation accompagnée de decarboxylation.