A Strategy toward the Biomimetic Synthesis of (±)-Morusalbanol A Pentamethyl Ether

A strategy toward the biomimetic synthesis of morusalbanol A pentamethyl ether is described. The synthesis is based on a hydrogen-bond-assisted Diels-Alder cycloaddition between a dehydroprenyl diene and a chalcone dienophile. Selective cleavage of the ortho-methyl ether of the resulting cycloadduct allows rotation of the C3-C21 bond and subsequent intramolecular cyclization affords the pentamethyl ether of (+/-)-morusalbanol A. As with the natural product, morusalbanol A, a number of key proton and carbon signals are absent in the NMR spectra of the title product.