MHz for 1 H, 100 MHz for 13 C). Chemical shifts are reported in ppm relative to the solvent in which the spectrum was recorded. Electrospray ionization (ESI) high resolution mass spectra were acquired at the ICMG PSM Platform on a LTQ Orbitrap XL Thermo Scientific. All tested compounds had purity higher than 95%, measured either by combustion analysis or by HPLC analysis. Combustion analyses were performed at the analysis facilities of the Molecular Chemistry Department. HPLC analyses were performed with a μ-bondapak-C18 analytical column (Waters Corporation, Milford, MA) on a Waters chromatographic system, equipped with two M-510 pumps and a photodiode array detector Waters 996, using Millenium 32 software. Silica gel UV254 plates (0.20 mm; Macherey-Nagel) were used for thin-layer chromatography (TLC), and silica gel 60 M (0.04-0.063 mm; Macherey-Nagel) was used for flash chromatography. Unless otherwise stated, reagents were obtained from commercial sources (mostly from Sigma, Alfa Aesar, Fluorochem) and were used without further purification. Compounds