Indenone Synthesis via Transition‐Metal‐Catalyzed Annulation

Abstract Transition‐metal‐catalyzed annulation reactions to synthesize indenones are reviewed, beginning with the Larock indenone synthesis and focusing on the most recent advances in technology. Proposed reaction mechanisms, and the evidence supporting them, are highlighted throughout this review. Current limitations in these reactions are described in detail. Obtaining high regioselectivity remains challenging with several different classes of alkyne. In particular, high‐yielding and regioselective reactions with alkyl‐substituted alkynes remain elusive, as do reactions with terminal alkynes. In the final section, the case is made that indanone synthesis reactions employing alkenes should be further explored. magnified image