Organocatalytic enantioselective Michael addition of β-diketones to β-nitrostyrene: The first Michael addition of dipivaloylmethane to an activated olefin

摘要

The addition of a family of β-diketones to β-nitrostyrene was explored using a library of cinchona organocatalysts. A thiourea organocatalyst, under improved reaction conditions, is shown to be much more efficient at catalyzing this reaction than previously reported giving excellent yields and enantioselectivites (up to 95% yield and 97% ee). The same thiourea organocatalyst was employed in the first successful Michael addition of the sterically challenging dipivaloylmethane to β-nitrostyrene (99% ee).