Design and preparation of a novel prolinamide-based organocatalyst for the solvent-free asymmetric aldol reaction
作者:Rafaela de S. Martins、Mathias P. Pereira、Pedro P. de Castro、Fernanda I. Bombonato
DOI:10.1016/j.tet.2019.130855
日期:2020.1
proline-derived catalyst, providing access to the desired adducts in up to 95% yield, 1:19 syn/anti and 98% e.e. Moreover, even sterically bulky aldehydes and substituted cyclohexanones were well tolerated. DFT calculations and control experiments indicated that several hydrogen bonding interactions between the aldehyde and the enamine intermediate are responsible for the stereoselective chiral induction process
描述了四种新型有机催化剂的制备,这些催化剂是用于无溶剂不对称醛醇缩合反应的高度非对映体和对映体选择性催化剂。这些有机催化剂使用简单的市售起始原料分八步合成。脯氨酸衍生的催化剂获得了最佳结果,以高达95%的收率,1:19合成/反合成获得所需的加合物和98%ee此外,即使空间上较大的醛和取代的环己酮也具有良好的耐受性。DFT计算和对照实验表明,醛与烯胺中间体之间的几种氢键相互作用是立体选择性手性诱导过程的原因,而三氟乙酸抗衡阴离子对于实现更高的立体选择性至关重要。