Development of (trimethylsilyl)ethyl ester protected enolates and applications in palladium-catalyzed enantioselective allylic alkylation: Intermolecular cross-coupling of functionalized electrophiles

Abstract

The development of (trimethylsilyl)ethyl ester protected enolates is reported. The application of this class of compounds in palladium-catalyzed asymmetric allylic alkylation is explored, yielding a variety of α-quaternary six- and seven-membered ketones and lactams. Independent coupling partner synthesis engenders enhanced allyl substrate scope relative to traditional β-ketoester substrates; highly functionalized α-quaternary ketones generated by the union of (trimethylsilyl)ethyl β-ketoesters and sensitive allylic alkylation coupling partners serve to demonstrate the utility of this method for complex fragment coupling. © 2014 American Chemical Society.