A Revised Protecting Group Strategy enables a Divergent Synthesis of Prenylated Isoflavones from Psoralea corylifolia

Three bioactive prenylated isoflavone natural products were synthesized for the first time, using a combination of Pd-catalyzed Suzuki-Miyaura-coupling for installing the B-ring, microwave promoted Claisen-rearrangement of allyl ethers, and Ru-catalyzed olefin cross metathesis for obtaining the prenyl substituents. Careful consideration of the protecting group strategy turned out to be vital for the success of these total syntheses.