Squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to nitroalkenes?

Organic & Biomolecular Chemistry Pub Date: 2013-07-24 DOI: 10.1039/C3OB41045E

Abstract

An efficient chiral squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to nitroalkenes has been developed. This reaction afforded the chiral pyrazol-3-ol derivatives in high to excellent yields (up to >99%) with high enantioselectivities (up to 94% ee) for most substrates under very low catalyst loading (0.25 mol%). This catalytic asymmetric reaction provides valuable and easy access to chiral pyrazol-3-ol derivatives, which possess potential pharmaceutical activity.

Graphical abstract: Squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to nitroalkenes
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