Clean and atom-economic synthesis of octahydroacridines: application to essential oil of citronella

A green and efficient method for the synthesis of octahydroacridine (OHA) has been developed by a simple one-pot hetero-Diels–Alder reaction starting from (+)-citronellal and N-arylamines in the presence of a solid supported catalyst (SiO2/ZnCl2), under MW irradiation and without any solvent. The method was used in the direct preparation of OHA from citronella oil in good yield.