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Unless otherwise stated, all glassware was oven-dried at 160°C or flame-dried under vacuum, assembled hot, and allowed to cool under nitrogen. All reactions were carried out open to air (under a CaCl2 guard tube). Reactions were monitored by thin-layer chromatography (TLC) and carried out on Merck silica gel 60 F254 analytical plates. Visualization of TLC plates was performed under ultraviolet (254 nm) or by staining with a solution of KMnO4 (2.5 g), Na2CO3 (15 g) in H2O (250 ml), phosphomolybdic acid (6.25 g), Ce (SO4)2.4H2O (2.5 g), and concentrated H2SO4 (15 ml) in H2O (235 ml). Yields refer to chromatographically or spectroscopically pure compounds. Silica gel 60 A (40 to 60 μm) from SDS was used for flash column chromatography (FC).

1H and 13C nuclear magnetic resonance (NMR) spectra were recorded on a 300-MHz spectrometer for 1H and on a 75-MHz spectrometer for 13C at 22°C. Chemical shift data are reported in units of δ (ppm) using the residual CHCl3 as the internal standard (δ = 7.26 for 1H NMR spectra and δ = 77.0 for 13C NMR spectra). The following abbreviations were used to explain the multiplicities: s (singlet), d (doublet), t (triplet), q (quadruplet), quint (quintet), sept (septuplet), hept (heptuplet), m (multiplet), and br (broad); the prefix app (apparent) was added when different coupling constants appeared accidentally equal. Coupling constants, J, are reported in hertz. Multiplicities were interpreted at the second order following Pople nomenclature when possible. Despite some apparent second-order contributions depending on the processing of the free induction decay (FID; for example, apodization function), some signals were approximated to the first order when the resolution was not sufficient. 13C NMR spectra were run using a proton-decoupled pulse sequence. The number of carbon atoms for each signal is indicated when superior to one. High-resolution mass spectrometry (MS) analyses were recorded on a hybrid quadrupole time-of-flight mass spectrometer using positive electrospray or on a double-focusing magnetic sector mass spectrometer. Infrared (IR) spectra were recorded on a Fourier transform IR spectrometer equipped with a Single Reflection Diamond ATR probe, and the values are reported in wave numbers (in cm−1). Gas chromatography (GC) analyses were performed on a Macherey-Nagel OPTIMA Delta-3 capillary column (20 m, 0.25 mm; carrier gas: He, 1.4 ml/min; injector: 220°C, split mode; flame ionization detector: 280°C, H2, 35 ml/min; and air, 350 ml/min). GC-MS analyses were carried out on a GC-MS fitted with a quadrupole mass analyzer using an electron impact at 70 eV and equipped with a Macherey-Nagel OPTIMA Delta-3 capillary column (20 m, 0.25 mm; carrier gas: He, 1.4 ml/min; and injector: 220°C split mode).

Unless otherwise stated, all commercial reagents were used as received. Solvents for the reactions (distilled CH2Cl2, tetrahydrofuran, and n-hexane) were filtered over columns of dried alumina under a positive pressure of argon. Solvents for extractions and FC were of technical grade and were distilled before use. Triethylborane solution (1 M in n-hexane) was prepared from pure triethylborane.

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