Selagibenzophenone A (1) and its isomer selagibenzophenone B (2) were recently described as natural products from Selaginella genus plants with PDE4 inhibitory activity. Herein, we report the first total syntheses of both compounds. By comparing spectroscopic data of the synthetic compounds with reported data for the isolated material, we demonstrate that the structure of one of the two natural products was incorrectly assigned, and that in fact isolated selagibenzophenone A and selagibenzophenone B are identical compounds. The synthetic strategy for both 1 and 2 is based on a cross-coupling reaction and on the addition of organometallic species to assemble the framework of the molecules. Identifying a suitable starting material with the correct substitution pattern is crucial because its pattern is reflected in that of the targeted compounds. These syntheses are finalized via global deprotection. Protecting the phenols as methoxy groups provides the possibility for partial control over the selectivity in the demethylation thanks to differences in the reactivity of the various methoxy groups. Our findings may help in future syntheses of derivatives of the biologically active natural product and in understanding the structure–activity relationship.

A facile and unified approach to the main selaginpulvilin's framework was achieved by catalytic [2 + 2 + 2]cyclotrimerization of a triyne with monosubtituted alkynes. The reaction proceeded with high "ortho" selectivity by using Wilkinson's catalyst (RhCl(PPh 3 ) 3 ) under ambient conditions with reasonable yields. The scope of the reaction with respect to the alkyne as well as the catalytic system was evaluated. The formal total modular syntheses of selaginpulvilin C and D were accomplished by transformation of the cyclotrimerization's products.

We report the first total synthesis of natural diarylbenzophenone selagibenzophenone C recently isolated from a plant species Selaginella tamariscina, traditionally used in folklore medicines. The framework of the natural compound is assembled via Suzuki‐Miyaura cross‐coupling and the addition of organometallic species. Following some ambiguities in the assignment of the structures for some of the natural products belonging to this compound class, the spectral data reported for the isolated selagibenzophenone C are carefully compared to the data of the synthetic product, and the structure of the natural product is confirmed.

We present a synthesis of novel silver complexes stabilized by bidentate ligands based on N-heterocyclic carbenes (NHC) linked with a bisamide linker. The ligand stabilizes the silver ion in a rare chelating mode. The synthesis of the complex depends on the equimolar ratio of the silver source and the ligand precursor. In case the excess of the silver source is used, the reaction leads to the formation of an unprecedented tetranuclear silver complex, stabilized by two equivalents of the ligand, where each of the silver atoms is coordinated by one NHC and one amide moiety. The silver complexes were applied as a catalyst in a multicomponent A 3 coupling and proved to be a very efficient catalyst. The reaction provided desired products in yields up to 96%, and the use of low catalytic loading, as low as 0.1 mol%, was possible without significantly compromising the effectivity of the reaction. Moreover, the complexes showed broad spectra of antimicrobial activity, with minimal inhibitory concentrations in the range of 1 to 31 μg/ml against several Gram-positive and Gram-negative bacteria and fungi. Presented complexes represent synthetically challenging molecules, which show great applicability in catalysis and outstanding potential as antimicrobial agents.

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