A very efficient and selective telomerization of 1,3‐butadiene with CO2 that leads to the δ‐lactone (3‐ethylidene‐6‐vinyltetrahydro‐2H‐pyran‐2‐one) was obtained using palladium acetate and tris(p‐methoxyphenyl)phosphine as a catalyst in the presence of p‐hydroquinone, N,N‐diisopropylethylamine, and acetonitrile. A high turnover number of 4500 with 96 % selectivity to the δ‐lactone was obtained after 5 h reaction at 70 °C. The reaction was deactivated by the presence of different 1,3‐dialkylimidazolium ionic liquids, possibly by the formation of stable and inactive palladium‐imidazole‐2‐ylidene carbenes.

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The chemical composition of the essential oil obtained by hydrodistillation of the aerial parts of Piper amalago, Piper mikanianum, and Piper xylosteoides was elucidated by gas chromatography (GC) and GC/mass spectrometry analyses. P. mikanianum and P. xylosteoides essential oils presented phenylpropanoids as their main compounds (67.89% and 48.53%, respectively) whereas P. amalago was rich in monoterpene and sesquiterpene hydrocarbons (84.95%). The essential oils obtained were investigated for their effect on newly hatched larvae of the cattle tick, Rhipicephalus (Boophilus) microplus. The essential oil of P. mikanianum (LC(50) 2.33 microL/mL) was more active than that of P. xylosteoides (LC(50) 6.15 microL/mL) against the larvae, while the oil of P. amalago was inactive. These results suggest that phenylpropanoids, mainly apiol and safrole, are responsible for the acaricidal activity.

The telomerization of 1,3‐butadiene with acetic acid catalyzed by palladium(II) acetate associated with a series of phosphines in 3‐(2‐methoxyethyl)‐1‐methylimidazolium acetate was used to investigate the role of the ionic liquid. The ionic liquid plays multiple roles in this reaction as it acts as the solvent, stabilizer, ligand, and cocatalyst. The reaction performed in the presence of Dan2phos, a trifluoromethylated sulfonated triarylphosphine, at 100 °C for 24 h gave a turnover number of 14 600 with 89 % selectivity to telomers at 75 % 1,3‐butadiene conversion and complete acetic acid conversion.