Catalytic Asymmetric [4 + 2] Cycloadditions and Hosomi–Sakurai Reactions of α‑Alkylidene β‑Keto Imides

Highly enantioselective catalytic asymmetric reactions of rationally designed α-alkylidene β-keto imides are described. The [4 + 2] cycloadditions and Hosomi–Sakurai reactions of α-alkylidene β-keto imides proceed with high enantioselectivity and yield. The [4 + 2] cycloadditions of the imides with various dienes afford products bearing an all-carbon quaternary stereogenic center at the ring junction. α-Alkylidene β-keto imides should be useful for the enantioselective total synthesis of natural products and other catalytic asymmetric applications.