Superparamagnetic Nanoparticle-Supported (S)-Diphenyl- prolinol Trimethylsilyl Ether as a Recyclable Catalyst for Asymmetric Michael Addition in Water
作者:Bang Gen Wang、Bao Chun Ma、Qiong Wang、Wei Wang
DOI:10.1002/adsc.201000508
日期:2010.11.22
A new superparamagneticnanoparticle-supported (S)-diphenylprolinol trimethylsilylether (Jørgensen–Hayashi catalyst) was synthesized and applied for the asymmetricMichaeladdition of aldehydes to nitroalkenes in water, which gives products in moderate to good yields (up to 96%), good enantioselectivity (up to 90% ee) and diastereoselectivities (up to 99:1). The immobilized catalyst could be easily
We report a synthetic strategy for construction of the first example of organocatalytic covalent organic frameworks via pore surface engineering. The COF catalyst combines a number of striking features, including enhanced activity, broad applicability, good recyclability, and high capability, to perform catalytic transformation under continuous flow conditions.
Asymmetric Conjugate Addition of Unmodified Propionaldehyde to β- Nitrostyrenes Catalyzed by Readily Available Proline-Based Dipeptidols
作者:Ren-Yong Yang、Chao-Shan Da、Lei Yi、Feng-Chun Wu、Hong Li
DOI:10.2174/157017809787003061
日期:2009.1.1
Organocatalytic asymmetric additions of unmodified aldehydes to β-nitrostyrenes are important carbon-carbon bond formation reactions and have become very attractive recently, because they are metal-free and environmentally benign. This work employed a series of L-proline-based diphenyl dipeptidols to catalyze this reaction. The results showed that these dipeptidols were effective organocatalysts with the yield up to 99%. 3a was optimal with the highest enantioselectivity up to 75% and dr (syn/anti) up to 94/6. In addition, the mechanism of this asymmetric reaction is also discussed.
Silicon can! A convenient synthesis of enantiopure (S)‐2‐(diphenylmethylsilyl)pyrrolidine is described and its organocatalytic activity in asymmetricMichael reactions is demonstrated (see scheme). By using 10 mol % of this novel organocatalyst, the addition of aldehydes to nitroolefins affords products with high stereoselectivities (d.r. ≤97:3 and e.r. ≤95:5) in yields up to 99 %.