Journal of the American Chemical Society, Vol.134, No.37, 15249-15252, 2012
Iridium-Catalyzed Regioselective and Enantioselective Allylation of Trimethylsiloxyfuran
We report the regio- and enantioselective allylation of an ester enolate, trimethylsiloxyfuran. This enolate reacts at the 3-position with linear aromatic allylic carbonates or aliphatic allylic benzoates to form the branched substitution products in the presence of a metallacyclic iridium catalyst. This process provides access to synthetically important 3-substituted butenolides in enantioenriched form. Stoichiometric reactions of the allyliridium intermediate suggest that the trimethylsiloxyfuran is activated by the carboxylate leaving group.