Synthesis of (1-Allylcyclohexa-2,5-dienyl)arenes

(1-Allylcyclohexa-2,5-dienyl)arenes are useful building blocks for the synthesis of natural products including amaryllidaceae, strychnos and morphinan alkaloids. Their synthesis was carried out in a straightforward manner starting from readily available cyclohexane-1,3-dione, through a palladium-mediated arylation―allylation sequence, which was used to install the quaternary center, followed by a transformation of the resulting 1,3-dione into the required diene through generation of a bis-silyl enol ether. After conversion of the latter into the corresponding bis-enol triflate, it was finally hydrogenated using palladium catalysis to give the title compounds.