화학공학소재연구정보센터
Catalysis Letters, Vol.146, No.3, 587-595, 2016
A Recyclable Organocatalyst for Asymmetric Michael Addition
In this study, a new organocatalyst derived from proline was developed and shown to be an efficient catalyst for asymmetric Michael addition reactions of ketones and aldehydes to nitroolefins with high diastereo- and enantioselectivities. (syn;anti up to 99:1, ee. up to 98 %.). Furthermore, the catalyst is easily recovered and could be reused six times without significant loss of its ability to affect the outcome of the asymmetric reactions. In addition, computational studies at the B3LYP/6311G(d, p)//6-311 + G(2dp, f) level was conducted on a model reaction, and confirmed the following hypotheses: first, the hydrogen bonding between carboxyl group and nitro group plays an important role in catalysis, and second, the energy barrier for re-face attack in reactions of ketones to form 2S, 3R products is lower than that for the si-face attack leading to 2S, 3R products.