Ring-Opening/Recyclization Cascades of Monoactivated Cyclopropanes

Abstract

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.

Transition‐Metal‐Free Synthesis of 1‐Indanone Skeleton: A Brief Update

“…An unprecedented ring‐opening/recyclization cascade of cyclopropyl aryl ketones 114 has been developed by Ramasastry group for the construction of indanone scaffolds in DMSO solvent (Scheme 37). [65] Depending on the nature of the electron withdrawing group (EWG) in 114 , synthesis of a variety of indanones and fluorenones with unusual substitution patterns is achieved under thermal conditions. For cyclopropyl keto‐aldehydes, the reaction produces 2‐(2‐hydroxyethyl)indenones 115 .…”