Ring-Opening/Recyclization Cascades of Monoactivated Cyclopropanes.

A variety of cyclopropyl aryl ketones undergo uncatalyzed cascade ring-opening/recyclization reactions to generate indenones and fluorenones. In addition, a new strategy to access 3-hydroxyindanones possessing two contiguous stereogenic centers, one of them being an all-carbon quaternary center, was also established. During the course of the investigation, pronounced solvent, temperature, and substituent effects on the product distribution were discovered.