An optimized multigram-scale
route to phototropone (bicyclo[3.2.0]hepta-2,6-dien-7-one)
is reported via the 4-π-photocyclization of tropone complexed
to Lewis acid. Phototropone is a highly versatile molecular building
block, and its conversion into 18 novel derivatives using standard
transformations is demonstrated, allowing access to a variety of rigid
bicyclic scaffolds.