Dipartimento di Scienze del Farmaco, Università di Catania , Viale Andrea Doria 6, 95125 - Catania, Italy.
Dipartimento di Scienze Chimiche, Università di Catania , Viale Andrea Doria 6, 95125 - Catania, Italy.
J Org Chem. 2017 May 5;82(9):4631-4639. doi: 10.1021/acs.joc.7b00227. Epub 2017 Apr 25.
A green and efficient 1,3-dipolar cycloaddition of nitrones with different styrenes and cinnamates using a catalytic amount of γ-cyclodextrin (γ-CD) in water has been developed to give substituted isoxazolidines. γ-CD was found to be highly efficacious in carrying out this reaction under an eco-friendly environment, affording moderate to excellent yields and, in some cases, excellent diastereomeric excess (up to >95%) at 100 °C in 8-12 h. The catalyst can be easily recuperated and recycled for several times without loss of activity. Water, an eco-friendly reaction medium, has been utilized for the first time, to the best of our knowledge, in this reaction. The credit of the presented protocol includes high yields and catalyst reusability, and precludes the use of organic solvents. The use of in silico calculations allowed us to rationalize the obtained results and to improve the stereoselectivity.
已开发出一种在催化量的γ-环糊精（γ-CD）存在下，在水中使不同的亚硝基化合物与苯乙烯和肉桂酸进行绿色高效的 1,3-偶极环加成反应，以得到取代的异噁唑烷。γ-CD 在环保的环境下进行此反应非常有效，在 100°C 下 8-12 小时内提供中等至优异的产率，在某些情况下具有极好的非对映过量（高达>95％）。催化剂可以很容易地回收并重复使用多次而不会失去活性。据我们所知，水作为一种环保的反应介质，首次被用于该反应。所提出的方案的优点包括高收率和催化剂的可重复使用性，并且避免了有机溶剂的使用。使用计算模拟允许我们合理化所得到的结果并提高立体选择性。
