Perchioric Acid Catalyied Homogeneous and Heterogeneous Addition of β-Dicarbonyl Compounds to Alcohols and Alkenes and Investigation of the Mechanism.

The direct addition of various β-dicarbonyl compounds to a series of secondary alcohols and alkencs has been achieved using I mol % pcrchloric acid (HCIO4) as the catalyst. The HCIO4-catalyzed reactions could be conveniently conducted in commercial solvent and gave moderate to excellent yields. Moreover, the silica gel-supported HCIO4 could also catalyze the heterogeneous addition for a series of substrates with similar or even higher yields in comparison with the homogeneous ones. The supported catalyst could be readily recovered and reused for four runs. Furthermore, the mechanism of' the HCIO4-catalyzed addition of the β-diketone to alcohol was investigated. and an SNI mechanism was proved unambiguously for the first time through a series of experiments. The discrimination of catalytic abilities among different Brensted acids was also rationalized by DFT calculations. [ABSTRACT FROM AUTHOR]