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چکیده
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Recently, the use of ionic liquids as solvent and catalyst has attracted much attention in the context of green synthesis [1]. Tetra-n-butylammonium bromide (TBAB) and related ionic liquids have considerable interest as potential ecofriendly reagents due to their lack of measurable vapor pressure. Recently TBAB has been used as an extremely useful catalyst in various organic transformations [2]. In recent years the reactions between NH-acids and acetylenic esters in the presence of various nucleophilic catalysts such as triphenylphosphine, trialkylphosphites, alkyl isocyanids, and tertiary amines have been widely investigated [3-5]. In most cases, these reactions carried out in organic solvents such as dichloromethane, chloroform, or in diethyl ether. In this work we wish to report regioselective nucleophilic conjugate addition of various solfonamides to alkyl propiolates in the presence of tetrabutylammonium bromide (TBAB) and sodium azid under solvent-free conditions at room temperature. Thus sodium azide catalized the regioselective Michel addition of various sofonamides to alkyl propiolates in the presence of TBAB to leads vinylated solfinamides in excellent yields.
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