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The binding of an alkene by Ni(tfd)2 [tfd = S2C2(CF3)2] is one of the most intriguing ligand-based reactions. In the presence of the anionic, reduced metal complex, the primary product is an interligand adduct, while in the absence of the anion, dihydrodithiins and metal complex decomposition products are preferred. New kinetic (global analysis) and computational (DFT) data explain the crucial role of the anion in suppressing decomposition and catalyzing the formation of the interligand product through a dimetallic complex that appears to catalyze alkene addition across the Ni-S bond, leading to a lower barrier for the interligand adduct. [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]

DFT calculations have been carried out to study the reactivity difference of B 2cat 2and B 2pin 2in the diboration reaction of alkenes catalyzed by carbene-ligated copper(I) complexes. The higher reactivity of B 2cat 2versus B 2pin 2in this reaction results largely from the enhanced electrophilicity/Lewis acidity of the former, which significantly lowers the barrier in the product-forming transmetalation step. Transmetalation reactions of B 2cat 2and B 2pin 2with (NHC)Cu−OMe have also been investigated, and the relative barriers are much closer than with analogous Cu−R systems. [ABSTRACT FROM AUTHOR]