| abstract |
Cyclopentene derivatives (I) ##STR1## where R 1 is isopropyl or isopropenyl, R 2 is alkyl of 1 to 3 carbon atoms, X is --CHO, a dialkyl acetal or 1,2- or 1,3-alkylene acetal thereof where the acetal radical is of 2 to 6 carbon atoms, --CH 2 OH or --CH 2 OCOR 3 where R 3 is hydrogen or alkyl or alkenyl of up to 3 carbon atoms. The manufacture of I from the corresponding halomethyl cyclopentenes and aldehydes R 2 --CH(CH 3 )--CHO in the presence of a base and a quaternary ammonium salt, followed if desired by acetalization or conversion of the --CHO group to the --CH 2 OH or --CH 2 O--CO--R 3 groups. The compounds are useful as fragrance materials. |