Cobalt π-cations in carbocyclic ring constructions

Article abstract of DOI:10.1016/S0040-4039(97)82966-8

In a combination of cobalt-mediated cationic and free radical chemistry, treatment of the allyl silane substituted β-hydroxycobaloxime 13 with pTSA led predominantly to the trans-disubstituted cyclopentane 14, which on irradiation with TEMPO produced 15. In a similar manner, the cobaloxine 18 was cyclised to 19 in the presence of pTSA which, on irradiation with a sunlamp then underwent radical mediated cyclisation to the substituted indane 20.