A General Synthesis of 2-Phenylselenenylenones. The Reaction of Unsaturated Ketones with a Phenylselenenyl Chloride/Pyridine Complex

The generation of specific enolates via Michael addition of nucleophiles to unsaturated ketones has proven to be an extremely useful process in organic synthesis. With regard to this we felt that the incorporation of a phenylselenenyl group in the 2-position of an enone would (a) enhance the ability of the enone to undergo Michael addition, (b) provide, after Michael addition, a stabilized enolate for the subsequent introduction of a substituent in the 2-position and (c) allow for the eventual introduction of a new double bond via the well-known selenoxide β-elimination reaction.¹ While a few 2-phenylselenenylenones have been previously reported in the literature,² no general method currently exists for their preparation.³ We now wish to report a general method for the synthesis of these systems in good yield under extremely mild reaction conditions. In future communications we will demonstrate the versatility of this class of compounds in a variety of enone mono- and dialkylation reactions.