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The direct addition of various [beta]-dicarbonyl compounds to a series of secondary alcohols and alkenes is achieved by using perchloric acid as the catalyst. The mechanism of the HCl[O.sub.4]-catalyzed addition of the [beta]-diketone to alcohol is examined and the discrimination of catalytic abilities among different Bronsted acids is rationalized by DFT calculations.

The ruthenium hydride complex RuH2(CO)(PPh3)3 was found to be an effective catalyst for the cycloaddition reactions of terminal alkynes and azides. In the presence of RuH2(CO)(PPh3)3, various azides reacted with a range of terminal alkynes to produce 1,4-disubstituted 1,2,3-triazoles with 100% selectivity and moderate to excellent yields. [ABSTRACT FROM AUTHOR]

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]