Synthesis of analogue structures of the p-quinone methide moiety of kendomycin

The synthesis of two model p-quinone methide ring systems of the antibiotic and antiosteoporotic compound kendomycin is reported. Two approaches were examined in detail, and the two-step (i) demethylation and (ii) DMDO oxidation were found to be reliable and generally applicable. Additionally, it was found that oxidation of a benzofuran by NaIO4 on silica produced a long-lived semiquinone radical.