Synthesis of benzo[g]chrysenes

A facile synthetic route toward diversified benzo[g]chrysenes 2 starting with commercially available isovanillin (1a) or 3-hydroxybenzaldehyde (1b) in modest total yields is described via the transformations of Claisen rearrangement of 3, Grignard addition of 4, DBU-promoted cyclodehydration of 5, and photolytic Scholl oxidative annulation of 6. Skeleton 3 is prepared via O-allylation of 1 with trans-cinnamyl bromide.