Studies on intramolecular alkylation. IV. The preparation of spirodienones from phenolic diazoketones

Abstract

The phenolic diazoketones (7; n = 3-7) were treated with boron trifluoride etherate in nitromethane. For n = 4, 5 and 6 spirodienones (8) were isolated as well as the respective benzocycloalkanones from a concomitant dienone-phenol rearrangement. The formation of (8; n = 4) constitutes the first demonstrated example of Ar₁-4 participation.