Oxidative Coupling of Lignans. III. Non-Phenolic Oxidative Coupling of Deoxypodorhizon and Related Compounds

Oxidative coupling of deoxypodorhizon (4) with thallium(III) oxide and trifluoroacetic acid may be controlled to give either deoxyisopodophyllotoxin (14) or isostegane (16). These results and those with related non- phenolic substances indicate that the aromatic substituents of the parent diarylbutane play an important role in determining the outcome of oxidative coupling.