Development of (Trimethylsilyl)ethyl Ester Protected Enolates and Applications in Palladium-Catalyzed Enantioselective Allylic Alkylation: Intermolecular Cross-Coupling of Functionalized Electrophiles
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.
Additional Information© 2014 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Received: February 3, 2014; Publication Date (Web): April 11, 2014. The authors declare no competing financial interest. The authors wish to thank NIH-NIGMS (R01GM080269), Amgen, the Gordon and Betty Moore Foundation, the Caltech Center for Catalysis and Chemical Synthesis, and Caltech for financial support. C.M.R. thanks the Rose Hills Foundation for a predoctoral fellowship. The authors thank Scott Virgil (Caltech) for helpful discussions and instrumentation assistance. Rob Craig (Caltech) and Dr. Allen Hong (Caltech) are thanked for helpful discussion.
Published - ol500355z.pdf
Supplemental Material - ol500355z_si_001.pdf