A convergent total synthesis of (-)-mucocin: an acetogenin from Annonaceae.

A total synthesis of the Annonaceous acetogenin mucocin has been accomplished. The synthesis follows a convergent strategy, wherein at a very late stage the left part of the molecule is connected with the right part. The key reaction is the stereocontrolled addition of an organomagnesium compound 2 to the aldehyde 3. The THP ring of mucocin is build by a 6-endo epoxide cyclization of an epoxyacetonide precursor (16 --> 17). The new modular synthetic approach developed herein should be useful for the synthesis of other related natural products as well as pharmacologically interesting analogues.