Enantioselective 1,6-Addition of β‑Ketoester Enolates to <i>In Situ</i> Generated <i>para</i>-Quinone Methides Enabled by Cooperative Palladium and Brønsted Acid Catalysis

We report herein an asymmetric cooperative process for the enantioselective 1,6-addition of β-ketoesters to in situ generated para-quinone methides with chiral Pd–aqua complexes as mixed Brønsted acid–base catalysts. Excellent yields, outstanding enantiocontrol, and good diastereoselectivity across a broad substrate range are highlights of this transformation. The utility of this reaction is further demonstrated by a facile scale up and subsequent complexity-increasing modifications