Asymmetric synthesis of (E)-Secobutanolides: total synthesis and structural revision of (+)-Litseakolide F and G

Optically active (E)-β-branched Morita-Baylis-Hillman (MBH) esters were prepared through a catalytic Michael-aldol MBH reaction and Z → E isomerization, which were successfully carried out using both photochemical and thermal methods. In this study, we report the first asymmetric synthesis of the (E)-Secobutanolide series and (+)-Litseakolide F and G, using an optically enriched iodo MBH ester. These investigations led us to propose revised structures for the natural products (+)-Litseakolide F and G.