Palladium-catalyzed α,β-dehydrogenation of acyclic ester equivalents promoted by a novel electron deficient phosphinooxazoline ligand
A unique example of Pd-catalyzed decarboxylative dehydrogenation of fully substituted N-acyl allyl enol carbonates is enabled by a new electron deficient phosphinooxazoline (PHOX) ligand. The reaction proceeds from the Z-enol carbonate to provide dehydrogenation products exclusively in high E/Z selectivity, while the E-enol carbonate provides the α-allylation product with only minor dehydrogenation. The reaction proceeds with a broad scope of Z-enol carbonates derived from N-acyl indoles to furnish acyclic formal α,β-unsaturated ester equivalents.
Additional Information© 2019 Published by Elsevier Ltd. Received 15 April 2019, Revised 24 May 2019, Accepted 29 May 2019, Available online 1 June 2019. Dedicated to Professor John F. Hartwig on his receipt of the Tetrahedron Prize. 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 assistance.
Accepted Version - nihms-1532523.pdf
Supplemental Material - 1-s2.0-S0040402019306271-mmc1.pdf