A general strategy for the synthesis of indolyl cyclopropanecarbaldehydes and ketones via a Brønsted acid-catalyzed indole nucleophilic addition/ring-contraction reaction sequence has been exploited. The procedure leads to a wide panel of cyclopropyl carbonyl compounds in generally high yields with a broad substrate scope.

A series of 6-aryl coumarin dyes were synthesized in satisfactory yields by Pd-catalyzed Suzuki cross-coupling reactions with a panel of boronic acids and coumarin bromides. Photophysical studies highlighted a large Stoke shift and interesting fluorescence quantum yield for these compounds. Optical properties were also investigated with the aid of quantum chemical calculations. The treatment of selected coumarin dyes with increasing amounts of trifluoroacetic acid showed that their fluorescence can be strongly influenced by pH (fluorescence quenching at high acid concentrations), while the addition of Fe 3+ and Al 3+ metal ions allowed to highlight dichotomous behavior with the corresponding reduction in fluorescence with the increase of [Fe 3+ ] or [Al 3+ ]. Finally, biological assays and fluorescence microscopy imaging investigations indicated that these compounds can be used as potential biomarkers in living and fixed cells.

A unified protocol for the construction of 3-(2bromoethyl)benzofurans and 2-(benzofuran-3-yl)ethylamines from bis[(trimethylsilyl)oxy]cyclobutene has been developed. This mild and facile strategy was applied for the synthesis of a series of 5-HT serotonin receptor agonists, underlining its potential for the syntheses of bioactive compounds and natural products.

The reaction between configurably stable -lithiated oxiranes (and aziridines) and 3-substituted cyclobutanones allows to obtain enantiomerically enriched cyclobutanols (er > 98:2). These adducts, subjected to base-mediated Payne rearrangement lead to...