Squaric acid as an impressive organocatalyst for Michael addition in water
作者:Najmadin Azizi、Elham Saki、Mahtab Edrisi
DOI:10.1016/j.crci.2011.07.003
日期:2011.11
Résumé A simple, green, and environmentally benign protocol for squaric acid (5 mg) catalyst conjugate addition of aromatic amines and thiols to unsaturated carbonyl compounds in water in good to excellent yields is developed. The advantages of low sensitivity toward moisture and oxygen, high tolerance of different functional groups, green reaction media and efficient recyclability make this organocatalyst suitable for both laboratory and industrial scale synthesis of β-substituted carbonyls under very mild conditions.
Yb(OTf)3 and Tb(OTf)3 to give the desired β-aminonitriles, β-amino sulfones, and dimethyl aspartates, respectively, in moderate to excellent yields. The reactions were carried out in toluene for Yb(OTf)3 and in t-BuOMe for Tb(OTf)3, all reactions were performed at 100 °C.