Synthesis of (−)-Piperitylmagnolol Featuring ortho-Selective Deiodination and Pd-Catalyzed Allylation

A 1,4-addition strategy using an enone and a copper reagent was studied for the synthesis of (−)-piperitylmagnolol. A MOM-protected biphenol copper reagent was added to BF3·OEt2-activated 4-isopropyl­cyclo­hexenone, whereas 1,4-addition of protected monophenol reagents possessing an allyl group was found to be unsuccessful. The allyl group was later attached to the p-,p′-diiodo-biphenol ring by Pd-catalyzed coupling with allylborate. The aforementioned iodide was synthesized using a new method for ortho-selective deiodination of o-,p-diiodophenols.