Applications of Weakly Coordinated Metal Salts [M(superscript n+)(Bar(superscript F)4)(superscript -)(subscript n)]in Acid Catalysis
Date Issued
2007
Date
2007
Author(s)
Liao, Bei-Sih
DOI
zh-TW
Abstract
Abstract
Metal salts, M(superscript n+)(Bar(superscript F)4)(superscript -)(subscript n) [M = Li、Na、K、Cs、Mg、Ca、Ag、Ni、Zn，ArF= 3,5-(trifluoromethyl)bromobenzene ], were prepared and employed as acid catalysts in aqueous medium. In addition to the Lewis acid property of metal ions, the hydrated metal ions associated with the tetraarylborate act as good Bronsted acid in water. Therefore, using these metal salts in catalyzing various reactions, such as preparation of bisindoles、Mannich reaction、Biginelli reaction、hydrolysis of acetal is investigated.
In fact, the anion [(BAr(superscript F)4)(superscript-)] plays an important role in catalysis. In water, metal salts of tetrakis[3,5-di(trifluoromethyl)phenyl]borate and organic substrates would form a colloidal dispersion during the reaction. The emulsion appeared to accelerate the reaction. These metal salts could be as catalysts and surfactants to promote various reaction in a micellar system.
Thus condensations or hydrolysis proceeded immediately under high concentration within the micelle. This procedure offers several advantages for the preparation of various organic compounds such as mild conditions, low loading of catalyst, high yields and in aqua medium, which make it a useful and attractive methodology for organic synthesis.
Subjects
酸催化
弱配位
Acid Catalysis
Weakly Coordinated
Type
thesis
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