Pd-catalyzed route to (±)-podophyllotoxin skeleton. Synthesis of the aryltetralin derivative

A new Pd-catalyzed route to (±)-podophyllotoxin is disclosed. The strategy is based on an efficient organoaqueous reaction that diastereoselectively introduces the C-4 hydroxyl group and the furan ring. Further functionalization led to an iododerivative, which was cyclized under optimized conditions either to the aryltetralin of (±)-podophyllotoxin or to a five-membered ring isomer.