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

✍ Scribed by Yi-Feng Wang; Wei Zhang; Shu-Ping Luo; Guang-Cun Zhang; Ai-Bao Xia; Xiang-Sheng Xu; Dan-Qian Xu

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 188 KB
• Volume: 2010
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.201000885

✦ Synopsis

Abstract

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.