Thermodynamic vs. kinetic control in the stereoselective intramolecular conjugate addition of amide enolates leading to chiral trans-3,4-disubstituted pyrrolidin-2-ones
作者:Roberta Galeazzi、Giovanna Mobbili、Mario Orena
DOI:10.1016/s0040-4020(99)00091-5
日期:1999.3
Intramolecular conjugate addition of amide enolates to α,β-unsaturated esters was found to give either of the diastereomeric trans-3,4-disubstituted pyrrolidin-2-ones 6, 10 or 7, 11 as the major products, by choosing the appropriate reaction conditions. The cyclisation performed with NaH in THF afforded mainly 6 and 10, whereas by using sodium ethoxide in ethanol the major products of the cyclisation
通过选择合适的反应,发现将酰胺烯酸酯分子内共轭加成到α,β-不饱和酯中可以得到非对映体反式-3,4-二取代吡咯烷-2-酮6、10或7、11的主要产物。情况。用NaH在THF中进行的环化反应主要得到6和10,而通过在乙醇中使用乙醇钠,环化的主要产物是异构体7和11,在C-3和C-4处的构型相反。这种行为通过热力学与动力学控制进行了解释,并得到了分子力学和量子力学计算的支持。