Tuning the Reactivity of Ketones through Unsaturation: Construction of Cyclic and Acyclic Quaternary Stereocenters via Zn-ProPhenol Catalyzed Mannich Reactions
作者:Barry M. Trost、Chao-I Joey Hung、Elumalai Gnanamani
DOI:10.1021/acscatal.8b04685
日期:2019.2.1
Zn-ProPhenol catalyzed Mannich reactions between N-carbamoyl imines and a-branched ketones. Despite only a small change in the substrate acidity, the bimetallic catalyst can preferentially recognize and activate unsaturated ketones over their fully saturated counterparts, providing a chemo-, diastereo-, and enantioselective route to valuable β-aminoketones bearing both cyclic and acyclic quaternary stereocenters
不饱和引入邻近羰大幅度改善了Zn的前酚的反应性催化之间曼尼希反应ñ -氨基甲酰基亚胺和一个支酮。尽管底物酸度仅有很小的变化,但双金属催化剂仍能优先识别并活化不饱和酮,而后者完全饱和,可以提供化学,非对映和对映选择性的途径,使有价值的β-氨基酮同时带有环状和非环状四元立体中心,它们是许多具有生物活性的生物碱中的常见基序。具有各种取代方式的不饱和酮和亚胺是可行的底物,并且该反应可以在低催化剂负载下以多毫摩尔规模进行,而不会影响其效率。更重要的是,通过亲核试剂引入的不饱和度为结构多样化提供了有用的平台。