A methodology for the one-step synthesis of cyclic polyalkene terpenoids in a low-polarity solvent (dichloromethane) by photoinduced electron transfer (PET) is described. For the efficiency of such processes in low-polarity solvents, the use of the cationic electron acceptor N-methylquinolinium hexafluorophosphate is vital. The first direct cyclizations of farnesol and geranylgeraniol to the corresponding all-

The combination of cationic acceptor NMQ with biphenyl as co-acceptor in a mixture of CH2Cl2/MeOH (4:1) is found to be efficient to perform cascade cyclizations of polyalkenes. Mono-and polycyclic terpenoids are formed in one step. For the first time the cyclization of farnesol (VI) and geranylgeraniol (XI) under photoinduced electron transfer conditions is achieved. -(OZSER, M. E.; ICIL, H.; MAKHYNYA, Y.; DEMUTH*, M.; Eur.