Total Synthesis of Denigrin E and Its Oxidative Conversion into Co-occurring Metabolite Denigrin D.

An unambiguous, six-step total synthesis of denigrin E ( 5 ) from anisaldehyde 22 has been achieved, confirming the structure of this marine natural product. On treatment with t -BuOOH/Mo(CO) 6 , compound 5 undergoes a unique and possibly biogenetically relevant oxidative rearrangement to generate the co-occurring metabolite denigrin D ( 4 ), which is obtained in 61% yield.