Acid-catalyzed rearrangement of cyclobutanones. VI. Syntheses of chrysenes and steroid-like substances

Cyclobutanones derived from 1-naphthylketenes and 1,3-cycloalkadienes were prepared. These undergo acid rearrangements under a variety of conditions to give tetracyclic ketones. The tetracyclic ketones were converted to chrysene and substituted cyclopentenophenanthrenes. A mechanistic scheme is proposed for the rearrangement process.