Photoinduced molecular transformations. Part 135. New synthesis of taiwanin C and justicidin E based on a radical cascade process involving β-scission of alkoxyl radicals generated from 3- and 8-aryl-1-ethyl-1,2-dihydrocyclobuta[b]naphthalen-1-ols prepared by thermolysis of (Z)-tert-butyl 3-amino-3-