Bifunctional Cinchona Alkaloid Catalyzed Vinylogous Michael Reaction of 3–Alkylideneoxindole with 4‐Oxo‐enoates: A Route to Chiral γ‐Keto Alkylideneoxindole Esters

A bifunctional cinchona alkaloid‐catalyzed vinylogous Michael addition reaction involving 3‐alkylideneoxindoles as the vinylogous nucleophiles and various β‐aroyl acrylates as the Michael acceptor is described. The reaction provides expedient access to functionalised chiral γ‐keto alkylideneoxindole esters in good to high yields and stereoselectivities (up to >19 : 1 d.r. and 92% ee).