Synthese des all-cis-Perhydronaphtho1,8-bcfuransystems durch Photocyclisierung

摘要

The diketone3was reduced to the diol which then was transformed to the tetracyclic diketal5by treatment with sodium in ethanol. Protection of the remaining hydroxy group was followed by hydrolysis of the dimethylketal. The resulting ketone7was stereoselectively converted to the tertiary alcohol by methyl magnesium chloride. Acidic retrograde aldol reaction of the tertiary alcohol led to the decalindione10, which was partially dehydrogenated by cupric chloride under basic conditions. The resulting endione1cyclized by light induced hydrogen abstraction and collapse of the resulting diradical to the perhydronaphtho1,8-bcfuran derivative.