Neighbouring group participation in the reduction of the diterpenoid fujenal
Abstract
Hydride reduction of the aldehyde-anhydride, fujenal, proceeds first at the C-7 aldehyde. This generates a C-7 alkoxide which then participates in the reactions of the C-6 carbonyl groups. C-6 → C-7 and C-6 → C-19 Lactones are formed. The structure of a C-6 → C-7 lactone was confirmed by X-ray analysis.