An Approach to the Core Skeleton of Lancifodilactone F

Two cycloaddition reactions were utilized for the construction of the 5,6,7-tricyclic skeleton of lancifodilactone F and buxapentalactone. A
[2+2] ketene cycloaddition reaction was first used to set their adjacent all-carbon quaternary centers at the 5,6-ring junction. An arene−olefin
meta-photocycloaddition reaction was then used to install the 6- and 7-membered rings concurrently.