Calcium-based Lewis acid catalysts.

Recently, Lewis acidic calcium salts bearing weakly coordinating anions such as Ca(NTf₂)₂, Ca(OTf)₂, CaF₂ and Ca[OCH(CF₃)₂]₂ have been discovered as catalysts for the transformation of alcohols, olefins and carbonyl compounds. High stability towards air and moisture, selectivity and high reactivity under mild reaction conditions render these catalysts a sustainable and mild alternative to transition metals, rare-earth metals or strong Brønsted acids.

Diastereoselective synthesis of indanes and tetralins via intramolecular Friedel-Crafts reaction.

An easy access to tetralin and indane skeletons has been developed using a diastereoselective intramolecular Friedel-Crafts alkylation. Treatment of diastereomeric mixtures of benzyl carbinols with a catalytic amount of Ca(NTf2)2/Bu4NPF6 yields the respective tetralin or indane in good yields with high levels of regio- and diastereoselectivity.

Cobalt-catalyzed C-SMe bond activation of heteroaromatic thioethers.

Cobalt-catalyzed activation of methylthio-substituted N-heterocycles facilitates either cross-coupling reactions with aryl- or benzylzinc compounds or synthesis of the corresponding zinc compounds.

Cobalt-catalyzed cross-coupling between in situ prepared arylzinc halides and 2-chloropyrimidine or 2-chloropyrazine.

A cobalt-catalyzed cross-coupling of aryl halides with 2-chloropyrimidines or 2-chloropyrazines is reported in satisfactory to high yields. The key step of this procedure is the formation of aromatic organozinc reagents and their coupling with 2-chlorodiazines using the same cobalt halide as catalyst and Zn dust under mild reaction conditions. This new cobalt-catalyzed coupling reaction represents a practical and interesting alternative to previously known methods for the synthesis of 2-aryldiazines.

Antifungal activity of synthetic di(hetero)arylamines based on the benzo[b]thiophene moiety.

The antifungal activity of several di(hetero)arylamine derivatives of the benzo[b]thiophene system was evaluated against clinically relevant Candida, Aspergillus, and dermatophyte species by a broth macrodilution test based on CLSI (formerly NCCLS) guidelines. The most active compound showed a broad spectrum of activity (against all tested fungal strains, including fluconazole-resistant fungi), with particularly low MICs for dermatophytes. Results from the inhibition of the dimorphic transition in Candida albicans and flow cytometry studies further confirmed their biological activity.

Cobalt-catalyzed cross-coupling reactions.

In the last few years, we and other groups have demonstrated that economical cobalt salts can advantageously replace expensive and toxic catalysts for cross coupling reactions. These cobalt-catalyzed reactions have considerably extended the range of functionalized compounds. A variety of sensitive functional groups can be tolerated in these coupling reactions and various organic compounds RX could be involved (R = alkyl, alkynyl, aryl, allyl and X = halides: F, Cl, Br, I and even triflates).