A chirally catalysed ene reaction in a novel formal total synthesis of the antitumor agent laulimalide

A short highly efficient synthesis of the C3C16 fragment 2 of laulimalide 1 is described. Fragment 2 was a key intermediate in a previous approach and thus constitutes a formal total synthesis with improved efficiency. The key steps are an Evans’ alkylation, a Brown allylation and a chirally catalysed stereocontrolled ene-reaction.