Chiral Squaramide‐Catalyzed Highly Enantioselective Michael Addition of 2‐Hydroxy‐1,4‐naphthoquinones to Nitroalkenes

A chiral squaramide‐organocatalyzed, highly enantioselective Michael addition of 2‐hydroxy‐1,4‐naphthoquinones to nitroalkenes has been developed. This reaction afforded the chiral naphthoquinones in excellent yields (up to 99%) and excellent enantioselectivity (up to 98% ee ) under very low catalyst loading (0.25 mol%). This organocatalytic asymmetric Michael addition provides an efficient alternative route toward the synthesis of chiral functionalized naphthoquinones.