Green chemistry procedure for the synthesis of cyclic ketals from 2‐adamantanone as potential cosmetic odourants

Synopsis Some cyclic ketals derived from 2‐adamantanone were obtained in excellent yields by microwave activation under solvent‐free conditions, as a ‘green chemistry’ procedure. A number of experiments were performed to evaluate the most efficient catalytic conditions. The best results were obtained using a simple heterogeneous mixture of reagents and p ‐toluenesulphonic acid as the catalyst, without any solvent or support. The data are reported and compared with those obtained by other microwave‐mediated syntheses or by classical method. In order to check the possible intervention of non‐thermal microwave effects, the best experiment in ‘dry media’ was carried out with considerable lower yield by conventional heating, in a thermostated oil bath, under the same conditions as under microwaves (time, temperature and vessel). All the synthesized compounds were tested for their olfactive character and for a potential cosmetic use. The odour evaluation is reported.