Highly Enantioselective Organocatalytic Michael Addition of 2‐Hydroxy‐ 1,4‐naphthoquinone to β,γ‐Unsaturated α‐Oxo Esters

An organocatalytic enantioselective Michael addition of 2‐hydroxy‐1,4‐naphthoquinone to β,γ‐unsaturated α‐oxo esters has been developed. The process was promoted by bifunctional chiral amine derived squaramides according to a hydrogen‐bonding mediated activation mechanism and afforded the chiral adducts in high yields (up to 88 %) and excellent enantioselectivity (up to 98 % ee ) under mild conditions. This organocatalytic asymmetric Michael addition provides an efficient route toward the synthesis of optically active functionalized naphthoquinones.