Enantioselective Synthesis of Sterically Hindered Tertiary -Aryl Oxindoles via Palladium-Catalyzed Decarboxylative Protonation. An Experimental and Theoretical Mechanistic Investigation

We have developed the first catalytic asymmetric preparation of sterically hindered tertiary -aryl oxindoles via enantioselective palladium-catalyzed decarboxylative protonation of the corresponding -aryl--amido allyl esters. The reaction occurs under very mild conditions and in short reaction times, providing excellent yields and promising enantioselectivities (ee's up to 78%). We have also performed an experimental investigation of the reaction mechanism and employed theoretical calculations to understand the nature of the enantioselectivity-determining step.