Palladium-catalyzed enantioselective decarboxylative allylic alkylation of fully substituted N-acyl indole-derived enol carbonates
The first enantioselective palladium-catalyzed decarboxylative allylic alkylation of fully substituted N-acyl indole-derived enol carbonates forming acyclic all-carbon quaternary stereocenters is reported. Excellent yields up to 99% and enantioselectivities up to 98% ee are obtained through the use of a new electron-deficient phosphinoxazoline (PHOX) ligand. Control of substrate enolate geometry is crucial for high selectivity. The obtained α-quaternary N-acyl indoles are formal ester equivalents, and represent a useful handle for further synthetic transformations.
© 2019 The Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Received 8th April 2019, Accepted 26th April 2019, First published on 17th May 2019. We thank NIH-NIGMS (R01GM080269), the Gordon and Betty Moore Foundation, and Caltech for financial support. E. J. A. thanks the National Science Foundation for a predoctoral fellowship. We thank Dr David VanderVelde (Caltech) for NMR expertise. Dr Scott Virgil (Caltech) is thanked for instrumentation and SFC assistance. Dr Michael Takase and Lawrene Henling are acknowledged for assistance with X-ray analysis. There are no conflicts to declare.
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