A new class of efficient poly(ethylene-glycol)-supported catalyst based on proline for the asymmetric Michael addition of ketones to nitrostyrenes

A new class of efficient poly(ethylene-glycol)-supported catalysts based on proline was designed to catalyze the asymmetric Michael addition of ketones to nitrostyrenes. Using 5 mol% of the best catalyst, the products of the Michael reactions were obtained in good yields (up to 94%), moderate to good enantioselectives (up to 86%) and high diastereoselectivities (>98/2, syn/anti ratios). The enantiomeric excesses were higher than those obtained with non-supported proline. Recovery and recycling of the poly(ethylene-glycol)-supported catalyst were also described.

Graphical abstractA new class of efficient poly(ethylene-glycol)-supported catalysts based on proline was designed to catalyze the asymmetric Michael addition of ketones to nitrostyrenes. Figure optionsDownload full-size imageDownload as PowerPoint slide